Статті в журналах з теми "Winding-On-Teeth"

This paper presents a two-dimensional (2D) exact subdomain technique in polar coordinates considering the iron relative permeability in 6/4 switched reluctance machines (SRM) supplied by sinusoidal waveform of current (aka, variable flux reluctance machines). In non-periodic regions (e.g., rotor and/or stator slots/teeth), magnetostatic Maxwell’s equations are solved considering non-homogeneous Neumann boundary conditions (BCs). The general solutions of magnetic vector potential in all subdomains are obtained by applying the interface conditions (ICs) in both directions (i.e., r- and θ-edges ICs). The global saturation effect is taken into account, with a constant magnetic permeability corresponding to the linear zone of the nonlinear B(H) curve. In this investigation, the magnetic flux density distribution inside the electrical machine, the static/dynamic electromagnetic torques, the magnetic flux linkage, the self-/mutual inductances, the magnetic pressures, and the unbalanced magnetic forces (UMFs) have been calculated for 6/4 SRM with two various non-overlapping (or concentrated) windings. One of the case studies is a M1 with a non-overlapping all teeth wound winding (double-layer winding with left and right layer) and the other is a M2 with a non-overlapping alternate teeth wound winding (single-layer winding). It is important to note that the developed semi-analytical model based on the 2D exact subdomain technique is also valid for any number of slot/pole combinations and for non-overlapping teeth wound windings with a single/double layer. Finally, the semi-analytical results have been performed for different values of iron core relative permeability (viz., 100 and 800), and compared with those obtained by the 2D finite-element method (FEM). The comparisons with FEM show good results for the proposed approach.

In this research, we focus on development of a new configuration of magneto-rheological fluid (MRF) based clutch (MRC) featuring a tooth-shaped disc with multiple teeth acting as multiple magnetic poles of the clutch. The tooth-shaped disc is placed in a clutch housing composed of the left housing and the right housing. The inner face the housing also has tooth shaped features mating with the teeth of the disc through the working MRF. Excitation coils are placed directly on stationary winding cores placed on both side of the clutch housing. An air gap of 0.3 mm is left between the housing and the winding cores to ensure the housing can freely rotate against the winding cores. After the introductory part, configuration of the MRC is introduced and the transmitted torque of the MRC is derived. An optimization process to minimize the overall volume of the proposed clutch, which can generate a required maximum braking torque, is then conducted. The optimal results show that the overall volume of the proposed MRC is significantly reduced compared to a referenced conventional MRC (0.159 m3 vs. 0.295 m3). A prototype of the proposed MRC is fabricated for experimental works and good agreement between the experimental results and simulated ones is archived.

The paper considers valve motors with toothed windings with pole numbers 2, 4, 6, 8, the main dimensions of which correspond to the 6DVM 300 valve motor manufactured by JSC “Cheboksary electrical apparatus plant”. This approach allows us to evaluate the effect of the number of stator teeth on the electromagnetic moment and its harmonic composition. The three adjacent coils of the toothed windings in question belong to three different phases. The paper analyzes the MMF of the windings and magnets of the rotor. The distribution of magnetic induction in the gap, the EMF of the stator winding and the electromagnetic moment are found based on the method of the specific magnetic conductivity of the gap. It is shown that the MMF curve of the stator winding consists of two multipolar rectangles of unequal height and width. Due to the non-sinusoidal distribution of magnetic field sources and the jagged inhomogeneity of the air gap, the curves of the phase EMF of the stator winding are also significantly non-sinusoidal. It is found that with an increase in the number of poles (from 2 to 8 poles) of the stator winding, the maximum induction in the air gap decreases from level 1 to 0.75 Tl, the average value of the electromagnetic moment increases from 120 to 160 Nm, the amplitude of the phase EMF remains unchanged, and the maximum (height of the rectangle) of the MMF of the stator winding is reduced from 2000 to 500 A.

Abstract Electric vehicles (EVs) need a wide speed and torque range for their reliable operation and working. Switched reluctance motors (SRMs) offer several advantages like high life cycle, meager cost, simple construction, robustness, good speed characteristics, and fault-tolerance, making it a suitable motor drive for EV application. The selection of independent variables like dimensions, winding turns, make materials, the number of slots, and the shape of rotor and stator teeth is a cumbersome task as SRM performance is mainly dependent on these parameters. This paper describes the methodology for selecting these independent variables by evaluating the SRM performance for different shapes of rotor and stator teeth, with the different stator and rotor materials, by taking all the design constraints like winding resistance, turns, and the number of slots. The EV drive performance is evaluated for the chosen independent variables and analyzed using JMAG software for determining the efficiency, Torque, and speed responses for comparison and analysis to get the optimal design constraints of the independent variables of SRM.

Subdividing stator winding is a way to lower the DC link voltage value in electric drives and reduce the stress on motor insulation. Coupled windings sharing the same stator teeth are modelled in order to evaluate the link between voltages disparities and current ripple. This paper provides an assessment of current ripple rise in the subdivided windings compared to ordinary topologies through the use of a basic inductive model. A method for PWM-Induced current ripple and high-frequency loss estimation based on admittance measurements is developed and experimentally validated. The use of this subdivided structure does not induce more than a 10% rise of the PWM-induced current ripple compared to a standard winding structure.

Purpose This paper aims to develop models and simulations focused on the prediction of electromagnetic forces acting on the stator core of a synchronous machine. It contributes to the study of stator core vibrations. Design/methodology/approach An analytical model based on the rotating fields’ theory including the damper winding contribution was developed. Such model allows the comprehension of airgap magnetic field distribution and the consequent pressure distribution. Focus was given to the pressure sub-harmonics due to the usual fractional winding configuration of low speed machines. A comparative numerical model was also developed and applied to an example laboratory machine. Partial validation measurements were performed. Findings The paper provides the predicted electromagnetic forces and the relative influences of damper winding and teeth tangential forces on each pressure harmonic. It is shown by how much such effects can influence the amplitude of pressure sub-harmonics from a fractional stator winding. Research limitations/implications The performed validation measurements were based on the airgap field distribution, but the resulting core vibration at load was not measured. Therefore, researchers are encouraged to perform additional tests for improved validation. Practical implications The obtained models and results are of great importance for the design phase of new generators and for the diagnosis process of existing machines with core vibration problems. Originality/value As a contribution of this paper, the magnitude of indirect effect of tangential forces and the effect of damper winding are comparatively quantified for each pressure harmonic. The given approach contributes to the relative evaluation of these effects especially on the sub-harmonics from the fractional stator winding.

The effective optimization methods are needed to reduce the thrust ripple for the tubular flux-switching permanent magnet linear motor (TFSPMLM), which is significant for reducing the vibration, and improving the reliability. The auxiliary teeth and core bridge are set and analyzed for the bipolar and single-polar winding structures. On this basis, this paper focused on a new method of the secondary pole pitch fine-tuning which can overcomes the disadvantages of increasing the volume, decreasing the average thrust, adding the cost, and so on. The influences of tuning the secondary pole pitch on the average thrust and the thrust ripple for the different winding structure motors are calculated and analyzed. The conclusion can provide reference for the application of the method of tuning secondary pole pitch to the TFSPMLM for different background demands.

Purpose The purpose of this paper is to present an improved winding function theory (IWFT) for performance analysis of surface mounted permanent magnet (SMPM) motors, which can precisely and simultaneously consider the impacts of stator slotting, the winding distribution, the magnetic flux density within PMs because of the armature reaction, the PM magnetization angle and the magnetic saturation,. Design/methodology/approach To obtain this improved analytical model, the conformal mappings (CMs) are introduced to calculate the relative complex permeance of slotted air-gap, which is used to obtain the function of slotted air-gap length. The equivalent magnetizing current model is used to extract the equivalent winding function for each PM pole. For retaining the basic assumption of WFT, the magnetic saturation is also considered by a proper increase in the air-gap length in the front of the stator teeth. Findings A new hybrid analytical model (HAM) based on WFT is presented in this paper, which can simultaneously and accurately consider the effects of slotting, the magnetic saturation, the variation of PM operating point and the winding distribution. In fact, IWFT removes all the drawbacks of the conventional WFT. Moreover, IWFT is more user-friendly and faster than other analytical and numerical techniques. Practical implications The obtained HAM can be used for design, optimization and fault diagnosis in electric machines. Originality/value This paper presents a new HAM for accurate modeling the SMPM motors, which includes different considerations of electromagnetic modeling. This new HAM can also be used for modeling the other electric motors.

As a result of the study of a two-dimensional finite element model of the magnetic field of a synchronous electric machine with fractional tooth windings, typical magnetic fluxes (fundamental, edge effect, scattering) in its magnetic system have been identified. The analysis of the degree of influence of magnetic fluxes of the edge effect and scattering on the magnitude of the main magnetic flux is carried out and equivalent circuits of the magnetic circuit of the studied synchronous electric machine with fractional tooth windings are constructed for different positions of the stator teeth relative to the rotor poles. An analytical model has been developed to determine the main magnetic flux through the coil of the working winding of a synchronous electric machine with fractional toothed windings. A feature of the proposed model is taking into account the dependence of the main magnetic flux through the coil of the working winding on the coordinate of the rotor position, the magnetic fluxes of the edge effect and scattering. The developed model allows solving the problem of quantitative determination of the value of the main magnetic flux through the coil of the working winding with high accuracy. In addition, the proposed model makes it possible to determine the influence of the main geometrical parameters of the magnetic circuit on the nature of the change in the main magnetic flux through the coil of the working winding with the least amount of time. The developed analytical model can be applied in the process of optimizing a synchronous electric machine with fractional tooth windings.

Purpose For a given rotor, the study of the impact of stator MMF from different winding distributions is usually carried out using analytical model under some simplifying hypotheses to limit time computation. To get more accurate results, finite element model is thus more suitable. However, testing different combinations of stator windings with the same rotor can be tedious when considering the stator slots. Indeed, this introduces mesh constraint, reluctance variation of the air gap and possibly taking into account of the connection between stator coils. To avoid this, a current sheet supplied such to represent the stator MMF and spread all around the inner slotless stator surface can be used. In addition, such an approach can be very useful to didactically assess the effect of each winding space harmonic on machine performance separately. The purpose of this paper is to use a current sheet coupled to an external analytical tool in order to easily test different windings or to quantify the effect of a given spatial harmonic of the winding. Design/methodology/approach In the proposed approach, the current sheet supply is obtained from an analytical tool that allows determining the spatiotemporal stator MMF of any winding considered. Moreover, stator teeth height is not modelled, and only the thickness of the stator yoke is considered along with the same air gap thickness. Results with the proposed approach are compared to the real stator modelling for two different winding configurations. Last, linear and non-linear magnetic material behaviours are investigated to validate the proposed approach in term of magnetic distribution. Findings For both studied cases, results in term of local and global physical quantities show good agreement between the real stator modelling and the proposed approach. Originality/value Current sheet is used with finite element model to study the inherent effect of different winding configurations on local and global physical quantities of an AC electrical machine. The proposed approach avoids the constraints in terms of stator slot geometry and electrical circuit definition. This is very useful to quickly test different winding configurations or to isolate a specific winding space harmonic to quantify its effect on the electrical performances. This cannot be performed using classical modelling as all space harmonics are taken into account.

The article deals with the issues related to the possibility of diagnosing the technical condition of an asyn-chronous electric motor by an external magnetic field. The justification of the problems associated with the di-agnosis of electric motors is given. The difficulties that arise when measuring the external magnetic field of electric motors, as well as the devices with which it is possible to carry out measurements, are described. The re-lationship between the EMF of the sensor and the external magnetic field is shown. The results of processing the EMF waveforms induced by an external magnetic field in an inductive sensor for various electric motors are presented. The processing was carried out by the fast Fourier transform method. The external magnetic field contains the first harmonic and various harmonics that are multiples of the combination of the stator teeth, or the sum of the stator and rotor teeth that fall on one pair of poles. The ratio of the amplitudes of the first and tooth harmonics is affected by the measurement location and the orientation of the sensor. Diagrams showing the ratio of the main and tooth harmonics at different points of the motor body are constructed. The depend-ences of the harmonic amplitudes on the magnitude of the magnetizing current of the stator are given. Changes in the amplitudes and spectrum of harmonics in the presence and absence of an inter-turn short circuit in the stator winding are shown. Diagrams of the circular external magnetic field for the main and higher harmonics are constructed. The study shows the possibility of using an external magnetic field to detect inter-turn short circuits of the stator winding.

Laminated structures can be represented computationally by the finite element method (FEM) using the homogenization procedure, which consists of the adjustment of equivalent orthotropic properties to a homogeneous structure. The application occurs in stators of electric machines composed of stacked laminated disks connected to each other through windings and other fastening components. This paper describes a method to the dynamic characterization of a typical laminated stator through the application of the homogenization technique to the magnetic core and consideration of the effect of winding contour conditions and screw joints. Two simplified three-dimensional models for the stator were compared. The first considers the application of a typical tightening of the fastening screws and the presence of a homogeneous isotropic volume representing the winding. The second considers the effect of the boundary condition of the winding on the region of the teeth of the nucleus in order to reduce the degrees of freedom of the complete model. The coupling between the components is accomplished through the application of modal synthesis methods, which require the definition of the surfaces and the type of connection between the components. The obtainment of the set of equivalent orthotropic properties is based on the minimization of residues related to the difference between the natural and experimental frequencies in the range of 0 to 10 kHz. This was carried out using the multiobjective genetic algorithm (MOGA) method used in conjunction with commercial Ansys® software. Both models presented satisfactory experimental correlation. The simplified model demonstrated limitations of representativeness emphasized in specific frequency bands.

Due to spiral winding, there is an inclination angle between the teeth and the direction of the tangential velocity of the licker-in, which makes the teeth obliquely work with the fibers instead of vertically. In the previous work in Part I, we discussed the impacts of this using theoretical mechanical analysis and a digital model in ANSYS Explicit Dynamics. Based on the analysis, this paper makes a new type of card clothing for the licker-in and manufactures the rack by adding a process in the processing for traditional AT5610 × 05611 racks. The comparison of the two slivers worked by the traditional and new design licker-in card clothing show that the new design clothing has an increase of 24.41% on nep removal, which is consistent with the theoretical analysis. According to the paired samples test, the trash removal ratio and the short fiber content in the sliver, this new design shows no deterioration. For further discussion, we collect the noils and calculate the producing rate of the sliver, licker-in droppings and card strips with special collecting equipment. This new design shows a significant increase in the fiber yield percentage (8.45%) and a dramatic decrease for licker-in droppings (33.6%). Yarns from the new rack have better performance on breaking elongation (a decrease of 5.6%) and evenness. Therefore, this design has higher utilization for fibers and good commercial benefit.

This paper investigates the effect of the field winding interturn short-circuit (FWISC) position on the rotor vibration properties in turbo generators. Different from the previous studies which focused on the influence of the short-circuit degree, this work pays much attention to the impact of the short-circuit position on the rotor unbalanced magnetic pull (UMP) properties and vibration characteristics. The theoretical UMP model is firstly deduced based on the analysis of the magnetic flux density (MFD) variation. Then, the finite element analysis (FEA) is performed to calculate the UMP data. Finally, the rotor vibrations are tested on a CS-5 prototype generator which has two poles and a rated capacity of 5 kVA. It is shown that the occurrence of FWISC will greatly increase the UMP as well as the rotor vibration. In addition to the short-circuit degree, the short-circuit position will also affect the UMP and vibration. The nearer the short-circuit position is to the big rotor teeth, the larger the UMP and vibration will be. The proposed study in this paper will be beneficial for the monitoring and diagnosis of FWISC faults.

The article presents the results of studies aimed at improving the power performance indicators of linear electric generators for wave power plants by reducing the flux leakages using high-temperature superconducting (HTS) inserts placed in between the teeth. The generator design involving application of the Vernier principle for magnetic flux modulation with a translator in the form of a hollow cylinder is considered. Generators of this type are used in float wave power plants driven directly by a reciprocating float, which transmits large forces at a low motion speed. The calculations were carried out using the HTS properties modeling procedure based on representing the currents induced in a superconductor in the form of magnetic moments of these currents, which made it possible to simplify the analysis of the electromagnetic field in the generator without significant additional errors. As a result, the characteristics of the electromagnetic force longitudinal components and phase winding flux linkages versus the translator displacement have been obtained. The use of HTS inserts and a distributed winding in the stator made it possible to reduce the electromagnetic leakage losses and increase the interaction force between the stator and translator. However, since the additional outlays for the cooling system and thermal insulation of the HTS elements are commensurable with the generator cost, the obtained results on improving the power performance parameters do not allow an unambiguous statement to be made about the effectiveness of the considered technical solutions.

An analytical model has been developed for calculating magnetic field in a multiphase synchronous electric machine with fractional toothed windings. For this, a harmonic analysis of the distribution functions of the magnetic field of excitation and the magnetic field of the armature reaction was carried out, taking into account the presence of higher harmonic components in the function of the magnetomotive force of permanent magnets, variable magnetic conductivity of the air gap, polyharmonic mode of operation of a multiphase electric machine and a non-sinusoidal law of variation of spatial winding functions. As a result of the analysis, the substantiation is given that in the investigated electric machine a nine-phase winding can extract with the greatest efficiency the harmonic components of the first and third order of a rotating magnetic field to create flux linkage and induce an electromotive force (as well as create a magnetomotive force with prevailing spatial harmonics of the first and third order). In the investigated electric machine, the amplitudes of the working harmonics of the induction of the modulated magnetic field of the armature reaction can be increased due to the modulation of the inoperative harmonics of the magnetomotive force of the armature response by the stator teeth to the first and third order. To check the developed provisions, a magnetostatic vector model of the magnetic field of the investigated electric machine was created. The simulation results confirmed the high efficiency of the developed analytical model for calculating the magnetic field in a synchronous electric machine with fractional toothed windings. The use of such a model will make it possible to reveal most reliably the influence of the geometricparameters of the magnetic circuit and the multiphase winding circuit on the nature of the change in the functions of the magnetic field in the air gap with the lowest time costs in the process of optimizing an electric machine.

A fault-tolerant permanent-magnet vernier (FT-PMV) machine is designed for direct-drive applications, incorporating the merits of high torque density and high reliability. Based on the so-called magnetic gearing effect, PMV machines have the ability of high torque density by introducing the flux-modulation poles (FMPs). This paper investigates the fault-tolerant characteristic of PMV machines and provides a design method, which is able to not only meet the fault-tolerant requirements but also keep the ability of high torque density. The operation principle of the proposed machine has been analyzed. The design process and optimization are presented specifically, such as the combination of slots and poles, the winding distribution, and the dimensions of PMs and teeth. By using the time-stepping finite element method (TS-FEM), the machine performances are evaluated. Finally, the FT-PMV machine is manufactured, and the experimental results are presented to validate the theoretical analysis.

Received:11 november 2020; Accepted: 27 December 2020; Published online: 05 April 2021 Abstract: Drones are used in agriculture and external control, utilizing cameras, various sensors, and autonomous flight functions. However, it is difficult to fly for a long time because of flying with heavy equipment. Therefore, it is necessary to increase the flight time through lightening of the drone itself and efficient control of the BLDC motor. That is, it is necessary to improve the motor itself, which accounts for most of the energy consumption in drone flight. Stator fabrication of existing BLDC motors is done by winding copper wires through individual processes on the stator core through an automated process. However, in the case of an ultra-small BLDC motor, the stator core has a small size and is manufactured using a thin-diameter copper conductor, and thus has a lot of problems in the automation process. Therefore, in this paper, the multi-division coupling structure method of individual teeth of the stator was applied through a new type of BLDC motor stator design. That is, the cartridge type BLDC motor stator was applied to improve and reduce the BLDC motor stator method. Through this, the performance limit of the BLDC motor was improved by combining individual teeth with multiple cartridges. The cartridge type BLDC motor is manufactured by stacking several cartridges on each tooth. Therefore, various performances can be produced according to the connection state of the cartridges

Stator and rotor winding damages in rotating machines are result of electrical, mechanical, and thermal stress. Online magnetic field monitoring via permanently installed measuring coils inside air gap is a well-established methodology which enables winding fault detection. The paper deals with a new method for detection of stator and rotor winding inter-turn short circuits of synchronous machines and slip rings induction machines, as well as rupture of rotor bars and cage ring of induction machines. The method novelty is based on differential measurement of magnetic field by using two serial connected measuring coils. They are installed on the places (stator or rotor teeth) in the machine which have, by absolute value, equal magnetic vector potential. The distance between the measuring coils is n·tp, where tp is a pole pitch, and n = 1, 2, 3, 4,... is a multiple of the pole pitch. Measuring the coil-induced voltage enables us to detect stator and rotor winding faults, which means that measured voltage is approximately zero without fault and increases in the presence of fault. Analysis of the measuring signal allows us to detect and locate fault. With this new method it is possible with high sensitivity to determine winding fault, which enables more reliable fault detection. For example, in comparison with the motor current signature analysis method (the most widely used method for motor faults detection), this new method gives 200 times higher sensitivity to fault occurrence. Also, by using the DMFM method, faults can be detected in the time domain and there is no need for spectral or other complex signal analysis. This is very important because the measuring equipment used for machine fault detection can be simple and more economically acceptable. The DMFM method enables fault detection for even small machines with small expense in a very effective way. The only downside of the DMFM method is the fact that machine should be disassembled in order to install measuring coils. This problem is solved during the machine overhaul or during the manufacturing of the machine, when sensors can be easily implemented in the machine. For machines with large air gap, measuring coils can be installed without a machine disassembly. For the purpose of the method testing, numerous finite-element (FE) simulations on the 2- and 3-D machine models have been carried out to verify the method. Powerful numerical tools generate realistic results with properly selected starting and boundary conditions. By FEM models, actual machines with embedded measuring coils where created and simulated. The voltage induced inside the measuring coils is calculated for different machine states, load point and with and without a fault (broken rotor bar or inter-turn short circuit). Also, this method was experimentally validated via series of laboratory tests performed on the real electric machines specially designed for fault study (broken rotor bars, broken ring and inter-turn short circuits in a stator and rotor winding). Additionally, this method is applied on more than 20 real machines in industry. Due to the large amount of measured data, in this paper, it will be presented only one measurement performed on an induction motor on which we have detected one broken rotor bar. The thickness of the measuring coil designed in the printed circuit board technique is 0.3 mm. The number of turns is from 3 to 10. This new method and performed FEM calculations together with the experimental measurements improve fault detection portfolio knowledge that can be used in monitoring and diagnostics of rotating machines. Furthermore, this patent-pending method is already implemented in three innovative products placed on market (expert monitoring systems), so this method is fully confirmed in practice.

Background: Aiming at the problems of high local temperature and uneven temperature distribution in asynchronous traction motor of high-speed Electric Multiple Unit (EMU) when it is running. Aim: In this paper, the influence of ventilation system with different structure on temperature distribution is studied. Methods: Taking 600kW asynchronous traction motor as an example, the electromagnetic-fluid-temperature analysis model of the traction motor is established, and the temperature values of different positions in the motor are obtained. The accuracy of the calculation results is verified by comparing with the actual measurement. On this basis, by adjusting the structure of stator and rotor axial ventilation holes, the relationship between temperature distribution and fluid flow state in motor is studied. In addition, the influence of fluid incidence angle on fluid velocity and heat dissipation performance of motor is also studied, and the ventilation structure scheme with relative balance of axial and circumferential temperature in motor is found out, which provides a reference strategy for the design of temperature rise of motor with forced ventilation structure. Results: The wind speed near the intake side of stator teeth and rotor teeth groove is less than that far from the intake side. The flow distribution trend of rotor vent is similar to that of stator vent, but the air in the groove is affected by centrifugal force of rotor rotation, which makes the wind speed difference on the intake side larger than that on the outlet side. The stator winding and rotor guide bar are affected by wind temperature to reach the maximum temperature at the end of the outlet respectively. The stator core is higher at the windward side and the leeward side than the other parts of the motor. The heat dissipation effect at both ends is good. The highest temperature of the stator core appears near the leeward side.

The inductive reaction sphere (RS) brings the benefit of simple, economical, and miniaturized design, and it is capable of multi-DOF torque generation. Thus, it is a suitable choice for the angular momentum exchange actuator in attitude control of micro-spacecrafts. To synthesize symmetric distribution of eddy currents and improve the speed and stability of rotation, a novel 4-pole winding design is proposed. However, the developed simplified analytical model shows that reduced pole number degrades the torque generation. To enhance the output torque of 4-pole RS, its curved cores and electromagnets are redesigned to enable the side teeth to be functional. As the analytical torque model for the RS with the slotted cores is not available, a constrained optimization problem is formulated, and the optimized parameters are calculated based on the prediction model from supported vector machine and finite element analysis. The lab prototypes are developed to validate the proposed design and test the speed performance. The experimental results show that the 4-pole RS prototype obtains a stable rotation over 700 rpm about X, Y and Z axis respectively with the angular momentum of 0.08 kg·m 2 /s, being superior to the 6-pole counterpart.

This paper aims to propose and compare three new structures of single-phase field excited flux switching machine for pedestal fan application. Conventional six-slot/three-pole salient rotor design has better performance in terms of torque, whilst also having a higher back-EMF and unbalanced electromagnetic forces. Due to the alignment position of the rotor pole with stator teeth, the salient rotor design could not generate torque (called dead zone torque). A new structure having sub-part rotor design has the capability to eliminate dead zone torque. Both the conventional eight-slot/four-pole sub-part rotor design and six-slot/three-pole salient rotor design have an overlapped winding arrangement between armature coil and field excitation coil that depicts high copper losses as well as results in increased size of motor. Additionally, a field excited flux switching machine with a salient structure of the rotor has high flux strength in the stator-core that has considerable impact on high iron losses. Therefore, a novel topology in terms of modular rotor of single-phase field excited flux switching machine with eight-slot/six-pole configuration is proposed, which enable non-overlap arrangement between armature coil and FEC winding that facilitates reduction in the copper losses. The proposed modular rotor design acquires reduced iron losses as well as reduced active rotor mass comparatively to conventional rotor design. It is very persuasive to analyze the range of speed for these rotors to avoid cracks and deformation, the maximum tensile strength (can be measured with principal stress in research) of the rotor analysis is conducted using JMAG. A deterministic optimization technique is implemented to enhance the electromagnetic performance of eight-slot/six-pole modular rotor design. The electromagnetic performance of the conventional sub-part rotor design, doubly salient rotor design, and proposed novel-modular rotor design is analyzed by 3D-finite element analysis (3D-FEA), including flux linkage, flux distribution, flux strength, back-EMF, cogging torque, torque characteristics, iron losses, and efficiency.

Twin pinion gear pumps are used widely in industrial hydraulics and as fuel-delivery pumps for aero engines. The kinematics of the pumping action leads to high-flow rates into and out of the meshing gears, and at the high speeds used with aerospace fuel pumps cavitation can occur. One-dimensional ‘lumped parameter’ models are often used to analyse this type of pump. These methods rely on an accurate description of the volume trapped by the meshing teeth and the flow areas during the meshing cycle. Typically, multiple computer-aided design models have to be created to calculate these values during the meshing cycle. This paper presents a mathematical method for calculating these parameters based on a parametric definition of the gear and inlet and outlet porting. Green's theorem is used to allow line integrals around the periphery of the tooth spaces to be used to calculate the volumes and flow areas. Winding numbers are used to calculate the inflow and outflow areas that are formed by the intersection of the trapped volume and the side area porting. The method is validated against computer-aided design model data. This method is well suited for incorporation in an optimisation algorithm since the geometry is defined parametrically.

In order to improve the suspension and torque performance of a bearingless flywheel machine, a new type of axial split-phase bearingless flywheel machine with a magnetic sleeve and pole-shoe tooth is analyzed and optimized as described in this paper. Based on the basic structure and working characteristics of the machine, the response surface methodology (RSM) and differential evolution (DE) algorithm are adopted to further optimize the parameters of the stator teeth of the machine to improve the radial space utilization and motor output performance. Firstly, the Box–Behnken design (BBD) and finite element analysis (FEA) are combined to select the representative optimization parameter combinations to establish the sample data space, and the response surface models of machine torque and suspension force are established using the least square method. Besides this, the DE algorithm is employed to obtain the optimal tooth profile parameter configuration for the multi-objective optimization of machine performance. Finally, the output performances of the machine before and after optimization are compared under initial and optimized winding turns. The results show that, compared with the initial structure, the average torque and suspension force of the optimized machine increase by 36.46 % and 108.22% respectively, which demonstrates the effectiveness of the tooth profile optimization method. At the same time, an experimental prototype is also produced, laying the experimental foundation for further practical exploration.

Purpose – With the popularization of permanent magnet linear synchronous machines (PMLSMs) in recent years, the temperature rise has attracted increasingly attention since excessive heat generated in the windings could deteriorate the electromagnetic performance. In order to solve this problem, adopting water-cooled system is an effective method. The purpose of this paper is to investigate a 12-slot/11-pole (12S/11P) water-cooled double-sided PMLSM, which adopts the all teeth wound concentrated winding and shifted armature ends. Design/methodology/approach – Based on 2D finite element analysis (FEA), the thermal performances, such as temperature distribution, the optimization of water flow rate and the influence of demagnetization, are investigated under the condition of continuous duty. Then the maximum current density and average thrust force are calculated for PMLSMs with or without water-cooled system. Finally, the detailed comparison is made between single-sided PMLSM and double-sided PMLSM. Findings – With water-cooled system, the thermal performance of PMLSM can be improved, such as an efficient decrease of temperature rise, restriction of permanent magnet demagnetization and a dramatic increase of the maximum thrust force. It is found that the water flow rate has a significant impact on temperature rise, which can be optimized according to demands. Originality/value – Electromagnetic and thermal coupled analysis is proposed in this paper. It can approximately predict thermal performance and save the manual iteration time at the same time. This method also can provide as a reference of thermal analysis for other PMLSMs.

Electrical rotating machines have a great economic significance as they enable conversion of energy between mechanical and electrical state. Reliability and operation safety of these machines can be greatly improved by implementation of continuous condition monitoring and supervisory systems. Especially important feature of such systems is the ability of early fault detection. For this reason, several methods for detection and diagnosis of the machine faults have been developed and designed. As fault detection methods can largely differ in the types of detectable faults, machine adoptability and price of the system, a novel method was developed that can be used for cost-effective detection of various faults of electrical machine. Machine fault detection technique presented in this paper is based on the measurement of magnetic field in the air gap. Numerous studies have proven that crucial information about the machine condition can be determined based on measurement and analysis of the magnetic field in the air gap. It has also been confirmed that analysis of the air gap magnetic field can be used to detect, diagnose and recognize various electrical faults in their very early stage. Proposed method of positioning and installation of the measuring coils on ferromagnetic core parts within the air gap region of the machine enables differentiation of various faults. Furthermore, different faults can be detected if measuring coils are placed on the stator teeth then when placed on the rotor side. The paper presents method on how to analyse and process the measured voltages acquired from measuring coils placed within the machine, especially in the case of rotor static eccentricity detection. The methodology is explained by means of finite element method (FEM) calculations and verified by measurements that were performed on the induction machine. FEM calculation model was used to predict measurement coil output of the induction motor for healthy and various faulty states (at different amounts of static eccentricity). These results were then confirmed by measurements performed in the laboratory on the induction traction motor that was specially modified to enable measurements of faulty operation states of the machine. Measurements comprised of several machine fault conditions broken one rotor bar, broken multiple rotor bars, broken rotor end ring and various levels of rotor static eccentricity. Other methods used for faults detection are primarily based on the monitoring of quantities such as current and vibration and their harmonic analysis. This new system is based on the tracing the changes of induced voltage of the measuring coils installed on the stator teeth. Faults can be detected and differentiated based on RMS value of these voltages and the number of voltage spikes of voltage waveform i.e. without the need of harmonic analyses. If these coils are installed on the rotor it is possible to detect the stator winding faults in a similar manner.

Purpose – Permanent magnet linear synchronous machines (PMLSMs) have large thrust ripple due to the longitudinal end effect caused by the finite length of the armature compared with rotary machines. The purpose of this paper is to analyze the influence of electric loading on thrust ripple performances based on a 12 slots/14 poles (12S/14P) PMLSM. Furthermore, the method of skewed PMs to reduce thrust ripple is investigated based on multi slices 2D finite element (FE) models. Design/methodology/approach – The thrust ripple of PMLSM under open-circuit condition results from the slotting and the longitudinal end effects. Therefore, periodical model has been designed to clarify the effect of the longitudinal end effect. Under on-load condition, the thrust ripple increases and exhibits an effective component of thrust force. To analyze the thrust ripple under on-load condition, frozen permeability (FP) technique is employed. In addition, the method of skewed PMs is analyzed in this paper to obtain more smooth thrust force performance. The effectiveness of skewing accounting for skew angles, step skew numbers and slot/pole number combinations was highlighted. Findings – The longitudinal end effect dominates the thrust ripple of PMLSM in both cases, i.e., open-circuit and on-load conditions. Under on-load condition, the second harmonic component of thrust ripple related to flux linkage harmonics increases significantly. Moreover, the effectiveness of skewed PMs is largely reduced with the increase of magnetic saturation. At last, a proper skew angle and step skew number are obtained for the conventional PMLSM with fractional-slot winding. Originality/value – By 60 electrical degrees and two or three step skewed PMs, the thrust ripple can be decreased to a tolerable limite for conventional PMLSM. The thrust ripple harmonics contributed by longitudinal end effect and flux linkage harmonics are analyzed, respectively, which is beneficial to exploring other techniques such as adding end auxiliary teeth to obtain lower thrust force pulsation.

(1) Background: One possible way to investigate the potential impact or susceptibility of buckling on different manual techniques is to measure compressive loads during canal negotiation. The higher their values, the easier and quicker the critical load level to buckling is reached, leading to possible instrument lateral deformation. The objective of the present study was to investigate the impacts of compressive loads on a small K-file manipulated with different techniques for canal negotiation in simulated narrow and curved canals. (2) Methods: The tooth model selected was a plastic double-curved premolar 23 mm long (DRSK Group AB, Kasernvagen 2, SE-281 35, Hassleholm, Sweden) with an extremely narrow canal lumen to mimic a very difficult anatomical scenario. An experienced endodontist performed the negotiation of 90 of these artificial teeth randomly assigned to 3 different groups of 30 blocks each, respectively, using 3 different techniques: Group A: watch winding/pull (WW) motion; Group B: balanced forces (BF) technique; Group C: envelope of motion (EOM). The measurement system was based on the use of a dynamometer, Instron, Ltd. (model 2525-818 2kN f.s.), linked to a data acquisition unit HBM MGC+ to test all the compression and tensile loads, including all the peaks. (3) Results: All data acquired were processed by the CATMAN AP HBM software. Multiple comparisons for the highest compressive loads estimated the mean difference between WW vs. BF techniques of 3.60 [95% confidence interval (CI): 2.85 to 4.35, p < 0.001], WW vs. EOM of −1.76 (95% CI: −2.11 to 1.40, p < 0.001), and BF vs. EOM −5.36 (95% CI: −6.04 to −4.67, p < 0.001). (4) Conclusions: In conclusion, among the tested manual motions, the BF technique (Group B) was the most susceptible to buckling with the highest compressive load. WW motion (Group A) and EOM (Group C) were less susceptible to buckling than the BF technique. Therefore, a pressure-free manipulation of manual files, such as WW motion or EOM, can help reduce the susceptibility to buckling during the negotiation of narrow-curved canals.

PM machines in which slot number and pole number combination differs by one have to be configured with asymmetric winding pattern in order to maximize it back-emf performance. However, this asymmetric winding configuration inherently results an unwanted Unabalanced Magnetic Force (UMF). Investigations of electromagnetic performance of fractional-slot asymmetric winding PM machines using 2-D Finite-Element Analysis are presented. The investigations are mainly driven by the effort of minimizing the UMF. By employing techniques such as non-uniform number of coil turns in every tooth and asymmetric design of stator tooth, the UMF are expected can be minimized. The investigations show that the radial component of UMF has greater effect than the tangential component on the UMF itself. In all proposed techniques, a slight reduction of machine torque performance is inevitable.

Background: Traction linear induction motors (LIM) at the current stage of human society development are the most promising for high-speed magnetic-levitation transport (MLT) and are already used in a number of commercial projects. Linear induction motors can be executed with longitudinal, transverse and longitudinal-transverse magnetic flux and have a large number of design options. Aim: In addition to traction efforts, LIM develops the forces of magnetic-levitation and lateral stabilization (self-stabilization). The efforts of magnetic-levitation of linear induction motors with longitudinal and transverse magnetic flux are very significant in the zone of large slides (at low speeds) and decrease with increasing speed of the magnetic-levitation transport. To a lesser extent, the decrease in slip (at high speeds) affects the magnetic-levitation forces developed by a number of design variants of linear induction motors with a longitudinal-transverse magnetic flux, in which magnetic fields traveling in a transverse direction towards each other are additionally used. This is explained by the fact that at high and low velocities MLT, the LIM slip will be equal to unity relatively oppositely running in the transverse direction of the magnetic fields and the magnetic suspension forces will be maximum. Materials and Methods: Running towards each other in the transverse direction of the MLT movement, magnetic fields cross the electrically conductive secondary element (playing the role of the track structure of the high-speed transport system) and induce electromotive forces in it, under the influence of which currents will flow. Results: As a result, cross counter-directional mechanical forces are created which, in the symmetrical arrangement of the MLT crew relative to the track structure, are mutually balanced and do not have any effect on the motion of the magnetic-levitation transport. At lateral (transverse) displacement of the high-speed transport on the magnetic suspension relative to the track structure, the equilibrium of the transverse mechanical forces is disrupted and, under the effect of the effort difference, the MLT crew will be automatically returned to the original symmetrical position. Conclusion: The distribution of magnetomotive forces (MMF) of a linear induction motor with a longitudinal-transverse magnetic flux, whose magnetic system is formed by the combination of longitudinally and transverse laminated cores, on the teeth of which the coils of a concentrated three-phase winding are located, is considered. The relations are represented in the form of a double Fourier series for calculating the resultant MMF value in the air gap of a linear induction motor with a longitudinal-transverse magnetic flux.

In this paper, two novel structures of linear double salient permanent magnet (LDSPM) motor having magnets and armature windings in primary are proposed and compared. Firstly, the design principles of both motors are presented. Then, for a fair comparison, two motors are designed based on the same primary dimensions including the slot area, teeth number, pole pitch, permanent magnet volumes and coils number per phase, while the stator pole pitch and the primary structure are different. Finally, the configurations and static characteristics of both motors are critically compared based on finite element (FE) analysis. The results indicate that the proposed topology can avoid the asymmetry of back-EMF waveforms and reduce cogging force and thrust force ripple. Also, the proposed primary permanent magnet linear motors are suitable for the longer stator application such as urban rail transit (URT).

There is a necessity to design a three-phase squirrel cage induction motor (SCIM) for high-speed applications with a larger air gap length in order to limit the distortion of air gap flux density, the thermal expansion of stator and rotor teeth, centrifugal forces, and the magnetic pull. To that effect, a larger air gap length lowers the power factor, efficiency, and torque density of a three-phase SCIM. This should inform motor design engineers to take special care during the design process of a three-phase SCIM by selecting an air gap length that will provide optimal performance. This paper presents an approach that would assist with the selection of an optimal air gap length (OAL) and optimal capacitive auxiliary stator winding (OCASW) configuration for a high torque per ampere (TPA) three-phase SCIM. A genetic algorithm (GA) assisted by finite element analysis (FEA) is used in the design process to determine the OAL and OCASW required to obtain a high torque per ampere without compromising the merit of achieving an excellent power factor and high efficiency for a three-phase SCIM. The performance of the optimized three-phase SCIM is compared to unoptimized machines. The results obtained from FEA are validated through experimental measurements. Owing to the penalty functions related to the value of objective and constraint functions introduced in the genetic algorithm model, both the FEA and experimental results provide evidence that an enhanced torque per ampere three-phase SCIM can be realized for a large OAL and OCASW with high efficiency and an excellent power factor in different working conditions.

The aim of this study is to calculate the optimum factor levels for the design parameters namely slot pitch, center slot pitch, and damper width to keep the magnetic flux density distribution in a desired range while minimizing the total harmonic distortion (THD). For this purpose, the numerical simulations are performed in the Maxwell environment. Then by the aid of regression modeling over this simulation results; the mathematical equations between the responses (THD and magnetic flux density distribution) and the factors are calculated. After the modeling phase, grasshopper optimization algorithm (GOA) is run through these regression equations to determine the optimum values of the rotor design parameters (factors). The confirmations are also performed in the Maxwell environment and the result indicated that the THD is minimized and the magnetic flux density distribution on the teeth is kept in a desired range.

A male elderly patient came with buccal mucosa swelling associated with tooth 46 and 47. Periapical radiograph confirmed the presence of periapical lesion and narrow root canals on both teeth. Challenging impediments were sensed upon negotiating most of the narrow root canals which were common in elderly patients. Glide path creation involved pre-flaring, K-file bending, watch winding movement, and very gentle strokes. After achieving patency, shaping, cleaning, and sealing phase can be performed.

Grain Oriented Electrical Steel (GOES) have better performance in terms of permeability and iron losses compared to conventional Fe-Si 3% Non-Oriented Grains Electrical Steel (NOES), particularly when it is magnetized in the rolling direction. This paper presents a concentrated winding radial flux permanent magnets synchronous machine (PMSM) equipped with teeth made of GOES sheet. The goal is to assess the suitability of the use of GOES sheets to improve the efficiency of electric motors. This work is based on the comparison of the performances (Joule losses, iron losses, losses in the permanent magnets and efficiency) of two iso-geometric motors: a reference motor made of NOES sheets and a motor with teeth made of GOES sheets, at iso-torque and over the operating range (at constant torque and flux weakening). The comparison is made using a finite element software application considering the magnetic anisotropy of the GOES sheets.

This paper proposes a novel flux switching claw pole machine (FSCPM) with soft magnetic composite (SMC) cores. The proposed FSCPM holds advantages of the conventional flux switching permanent magnet machine (FSPMM) and claw pole machine (CPM) with SMC cores. As permanent magnets are installed between the stator claw pole teeth, FSCPM has good flux concentrating ability, and the air gap flux density can be significantly improved. The torque coefficient of FSCPM is relatively high due to the applied claw pole teeth and global winding. FSCPM is mechanically robust because there are no windings or PMs on its rotor. Moreover, the core loss of FSCPM is relatively low for the SMC material has lower core loss at high frequency compared with silicon steels. The topology and operational principle of FSCPM are explained first. Several main dimensions of the machine are optimized to achieve better performance, based on 3D finite element method (FEM). Furthermore, the rotor skewing technology is adopted to reduce the cogging torque and torque ripple.

Reluctance machines with DC field coil in stator are a competitive candidate for starter generation application, due to the elimination of rare-earth permanent magnet (PM), robust structures, and controllable excitation. However, due to the poor excitation ability of DC field coils, the torque density is disadvantageous. Moreover, with the increase in the DC field current, it is exposed to the risk of extra DC saturation in stator teeth. As a consequence, the torque density and efficiency are both constrained. To solve the aforementioned problems, based on the comprehensive consideration of production cost and torque performance, this study proposed a novel type of hybrid reluctance machine with dual-ferrite–assisted in stator slots. The inner-layer ferrite PM is magnetized tangentially, which can effectively achieve the DC-saturation–relieving effect, while the outer-layer ferrite PM is magnetized radially to increase the machine torque density through the flux modulation effect. Based on finite element analysis, the machine torque density and efficiency can be improved by 20 and 5%, respectively. Furthermore, to simplify the excitation system of the DC terminal, a two-stage excitation method is proposed by splitting some turns of armature winding to feed DC field winding with passive rectifier. No power switching devices are needed for the excitation system in this way, making the system highly robust. The effectiveness of the proposed design is verified by time-stepping finite element analysis.

Background: The existing literature depicts that, since the advent of the hybrid permanent magnet switched-flux memory motor (HPMSF-MM), comprehensive research is focused on the design of three (3)-phase HPMSF-MM topologies, which limits their practical safety crucial design application range or scope, namely, in electric vehicle (EV). Objective: This research work aims to design a novel five (5)-phase fault-tolerant HPMFS-MM using the synergy of two key PMs, namely, a neodymium magnet (NdFeB) and Alnico magnet, also known as low coercive force (LCF) with an intrinsic overload fault detection capacity and excellent flux-regulation capacity to extend it practical application scope. Methods: This research paper employs finite element analysis (FEA) via ANSYS Maxwell electromagnetic software in designing, simulation, and analyzing the proposed fault-tolerant HPMSF-MM. Results: The key merit of the Proposed HPMSF-MM, is the exhibition of an overload fault protection mechanism via an injection of a reversed temporary control pulse current into the field winding (FW) in an event of an overload fault condition, to demagnetize the Alnico PM configuration to ensure that, almost all the generated flux are short-circuited via the design stator-core without linking the designed rotor as in the case of normal operation is effectively verified via the flux-linkage analysis in this paper. Conclusion: The proposed HPMFS-MM can effectively demonstrate its intrinsic overload fault detection mechanism, due to its tremendous flux-regulating or weakening capacity, in addition to its fault-tolerant teeth implementation merit of ensuring physical motor winding phase isolation in an event of a fault.

"So which is the most authentic experience for an end-user steeped in car culture? Real, made-in-Japan Type R? Or virtual, programmed-in-Japan Type-R. Each Type-R is equally enjoyable, equally wieldy, equally consistent -- and precisely fulfils the sporting intent of Honda's Type-R sub-brand. Car culture, then, is so broad, so diverse, that we might now have got to a point where actual driving, all the bum-on-seat, wind-in-hair, aphid-in-teeth, tradly, dadly stuff we were weaned on is peripheral... Who needs reality, anyway?" -- Russell Bulgin, Car Magazine, August 1998 (53) "Such would be the successive phases of the image: it is the reflection of a profound reality; it masks and denatures a profound reality; it masks the absence of a profound reality; it has no relation to any reality whatsoever: it is its own pure simulacrum." (Baudrillard 6) A Personal Prehistory of Racing Sims The very first racing sim I used was an arcade machine on the Gold Coast sometime during the mid-seventies. A coin-operated cabinet where a boy and his dad could stand and move a plastic steering wheel from side to side. This controlled a plastic model racing car attached to a stick. I kid you not. Youth was further misspent on large four-up machines, with a simple overhead view of a square-cornered, maze-like track. Each driver had a certain coloured 'car' to control round the electronic labyrinth in real time. The revolution moved into the living room, and a Hanimex TV game. Something of a poor man's Atari 2600, the driving sim was the overhead view of an endless straight track -- 'driving' was the act of jabbing a joystick left or right to avoid oncoming traffic. Addictive until the repetitive pattern of avoidance was committed to memory. Finally, there was an Apple II --and perhaps my first true racing sim. No overhead imagery, or even representations of cars. Just a first-person view down an imaginary winding road, as the view shuffled left or right using a knob-shaped controller. A Coming of Age Today, reputable motoring journalists dare to compare driving a Honda sports car on a Sony Playstation with driving a Honda Integra in real life, and deriving similar levels of satisfaction from each. This, mind you, on a two-generations-old, soon to be superseded piece of hardware with relatively chunky graphics hooked up to a mildly archaic television screen. Using a couple of buttons as a controller. When the immersion becomes more complete -- when graphics chips render more and more polygons at ever faster speeds, when the visual virtual is displayed on a wrap-around plasma in a real racing helmet, where control is provided by a force-feedback steering wheel in a vibrating bucket seat, what then... The latest racing sim I used was at Sega World in Sydney. Eight IndyCar machines, all giant 50" screens, mechanical vibrating seats and shuddering steering wheels. The physics engines sucked. Purists would call it more of a game, and less of a sim; but I still walked away with sweaty palms, shaky legs and a moment of nausea. But you ain't seen nothing yet... indeed the Nascar Silicon Motor Speedway in the USA has taken the concept to the next appropriate level -- a dozen real Nascar racers mounted on rocking. rolling motion generators in front of enormous projection screens. And So to the Network The crazies buy fibreglass tubs and strap themselves into racing seats. Jacques Villeneuve apparently learnt the layout of F1 tracks from his PC, before he scored a Formula One drive, and promptly went out and won the world championship in his second season. And the real crazies do it to each other. There are dial-in racing boards all over the USA and the racing mob have taken to the Internet in a big way. Nascar runs a league for on-line racers, who participate in a season of speedway much like that of their heroes. Indeed, the official body of V8 metal munchers in the good old USA is talking about running hybrid races -- inserting virtual images onto real races, and allowing online competitors to compete against their heroes in real time. We're a little way from that technologically -- V90 modems and Voodoo II cards may do the job for the moment, but utopian racing simulations will require Moore's Laws for a few more years yet. Nevertheless, it's way less than a single human generation since playing with a car glued to a stick was considered pretty cool. What of It? It may indeed be time to invoke the appropriate french philosopher. Whilst anecdotal evidence exists of world champions learning formula one race tracks using PC simulators, the reality is that racing sims are a simulacrum for most of us. Few of us have the opportunity, let alone the courage, to partake in the act of driving cars fast. Either on the road, on on a race track. Indeed, when it can take 15 minutes to move a mile in peak hour traffic, it is tempting to suggest that the entire notion of car-culture, which this society holds dear to its heart, be moved to simulation, so that the rest of us can just get on with the job of getting from A to B as efficiently as possible. As participants, racing sims -- even driving sims -- don't exist in real life. A daily commute across the harbour bridge is, in reality, nothing like we imagine the real thing should be. Crawling, foot riding on clutch, through slow-moving traffic, is as far from the dream of freedom that the motorcar suggests as, well, as sitting in front of a Playstation or PC. In fact, the computer does more than represent a simulation of driving. It represents the new freedom. The question is though, in Baudrillard's precession of simulacra, where exactly are we at? If one accepts that the reality represented by a racing sim does not exist; then does this new escapism mask the absence of a profound reality? Is the hyperreality that is the sweaty palm on plastic wheel merely a confirmation that we live in a hyperreality? As he describes Disneyland, "it is no longer a question of a false representation of reality ... but of concealing the fact that the real is no longer real" (12). There is no escape machine for the overworked stressed young executive; there is no sports car or highway that can give you a day's respite from the pressures of consumption; there is no road to Tijuana, no Corvette summer, no Highway 66. There is no Bathurst 1000, Le Mans or Monte Carlo where men can be men and leave behind the grinding reality. There is, in fact, no escape at all -- there is only cyberspace! References Jean Baudrillard. "The Precession of Simulacra." Simulacra and Simulation. Ann Arbor: U of Michigan P, 1994. Citation reference for this article MLA style: Sherman Young. "Racing Simulacra?" M/C: A Journal of Media and Culture 1.5 (1998). [your date of access] <http://www.uq.edu.au/mc/9812/racing.php>. Chicago style: Sherman Young, "Racing Simulacra?" M/C: A Journal of Media and Culture 1, no. 5 (1998), <http://www.uq.edu.au/mc/9812/racing.php> ([your date of access]). APA style: Sherman Young. (1998) Racing simulacra? M/C: A Journal of Media and Culture 1(5). <http://www.uq.edu.au/mc/9812/racing.php> ([your date of access]).

This essay combines life writing with meditations on the significance of walking as integral to the ritual practice of pilgrimage, where the individual improves her soul or health through the act of walking to a shrine containing healing relics of a saint. Braiding together insights from medieval literature, contemporary ecocriticism, and memory studies, I reflect on my own pilgrimage practice as it impacts the land itself. Canterbury, England serves as the central shrine for four pilgrimages over decades: 1966, 1994, 1997, and 2003.The act of memory was not invented in the Anthropocene. Rather, the nonhuman world has taught humans how to remember. From ice-core samples retaining the history of Europe’s weather to rocks embedded with fossilized extinct species, nonhuman actors literally petrifying or freezing the past—from geologic sites to frozen water—become exposed through the process of anthropocentric discovery and human interference. The very act of human uncovery and analysis threatens to eliminate the nonhuman actor which has hospitably shared its own experience. How can humans script nonhuman memory?As for the history of memory studies itself, a new phase is arguably beginning, shifting from “the transnational, transcultural, or global to the planetary; from recorded to deep history; from the human to the nonhuman” (Craps et al. 3). Memory studies for the Anthropocene can “focus on the terrestrialized significance of (the historicized) forms of remembrance but also on the positioning of who is remembering and, ultimately, which ‘Anthropocene’ is remembered” (Craps et al. 5). In this era of the “self-conscious Anthropocene” (Craps et al. 6), narrative itself can focus on “the place of nonhuman beings in human stories of origins, identity, and futures point to a possible opening for the methods of memory studies” (Craps et al. 8). The nonhuman on the paths of this essay range from the dirt on the path to the rock used to build the sacred shrine, the ultimate goal. How they intersect with human actors reveals how the “human subject is no longer the one forming the world, but does indeed constitute itself through its relation to and dependence on the object world” (Marcussen 14, qtd. in Rodriguez 378). Incorporating “nonhuman species as objects, if not subjects, of memory [...] memory critics could begin by extending their objects to include the memory of nonhuman species,” linking both humans and nonhumans in “an expanded multispecies frame of remembrance” (Craps et al. 9). My narrative—from diaries recording sacred journey to a novel structured by pilgrimage—propels motion, but also secures in memory events from the past, including memories of those nonhuman beings I interact with.Childhood PilgrimageThe little girl with brown curls sat crying softly, whimpering, by the side of the road in lush grass. The mother with her soft brown bangs and an underflip to her hair told the story of a little girl, sitting by the side of the road in lush grass.The story book girl had forgotten her Black Watch plaid raincoat at the picnic spot where she had lunched with her parents and two older brothers. Ponchos spread out, the family had eaten their fresh yeasty rolls, hard cheese, apples, and macaroons. The tin clink of the canteen hit their teeth as they gulped metallic water, still icy cold from the taps of the ancient inn that morning. The father cut slices of Edam with his Swiss army knife, parsing them out to each child to make his or her own little sandwich. The father then lay back for his daily nap, while the boys played chess. The portable wooden chess set had inlaid squares, each piece no taller than a fingernail paring. The girl read a Junior Puffin book, while the mother silently perused Agatha Christie. The boy who lost at chess had to play his younger sister, a fitting punishment for the less able player. She cheerfully played with either brother. Once the father awakened, they packed up their gear into their rucksacks, and continued the pilgrimage to Canterbury.Only the little Black Watch plaid raincoat was left behind.The real mother told the real girl that the story book family continued to walk, forgetting the raincoat until it began to rain. The men pulled on their ponchos and the mother her raincoat, when the little girl discovered her raincoat missing. The story book men walked two miles back while the story book mother and girl sat under the dripping canopy of leaves provided by a welcoming tree.And there, the real mother continued, the storybook girl cried and whimpered, until a magic taxi cab in which the father and boys sat suddenly appeared out of the mist to drive the little girl and her mother to their hotel.The real girl’s eyes shone. “Did that actually happen?” she asked, perking up in expectation.“Oh, yes,” said the real mother, kissing her on the brow. The girl’s tears dried. Only the plops of rain made her face moist. The little girl, now filled with hope, cuddled with her mother as they huddled together.Without warning, out of the mist, drove up a real magic taxi cab in which the real men sat. For magic taxi cabs really exist, even in the tangible world—especially in England. At the very least, in the England of little Susie’s imagination.Narrative and PilgrimageMy mother’s tale suggests how this story echoes in yet another pilgrimage story, maintaining a long tradition of pilgrimage stories embedded within frame tales as far back as the Middle Ages.The Christian pilgrim’s walk parallels Christ’s own pilgrimage to Emmaus. The blisters we suffer echo faintly the lash Christ endured. The social relations of the pilgrim are “diachronic” (Alworth 98), linking figures (Christ) from the past to the now (us, or, during the Middle Ages, William Langland’s Piers Plowman or Chaucer’s band who set out from Southwark). We embody the frame of the vera icon, the true image, thus “conjur[ing] a site of simultaneity or a plane of immanence where the actors of the past [...] meet those of the future” (Alworth 99). Our quotidian walk frames the true essence or meaning of our ambulatory travail.In 1966, my parents took my two older brothers and me on the Pilgrims’ Way—not the route from London to Canterbury that Chaucer’s pilgrims would have taken starting south of London in Southwark, rather the ancient trek from Winchester to Canterbury, famously chronicled in The Old Road by Hilaire Belloc. The route follows along the south side of the Downs, where the muddy path was dried by what sun there was. My parents first undertook the walk in the early 1950s. Slides from that pilgrimage depict my mother, voluptuous in her cashmere twinset and tweed skirt, as my father crosses a stile. My parents, inspired by Chaucer’s Canterbury Tales, decided to walk along the traditional Pilgrims’ Way to Canterbury. Story intersects with material traversal over earth on dirt-laden paths.By the time we children came along, the memories of that earlier pilgrimage resonated with my parents, inspiring them to take us on the same journey. We all carried our own rucksacks and walked five or six miles a day. Concerning our pilgrimage when I was seven, my mother wrote in her diary:As good pilgrims should, we’ve been telling tales along the way. Yesterday Jimmy told the whole (detailed) story of That Darn Cat, a Disney movie. Today I told about Stevenson’s Travels with a Donkey, which first inspired me to think of walking trips and everyone noted the resemblance between Stevenson’s lovable, but balky, donkey and our sweet Sue. (We hadn’t planned to tell tales, but they just happened along the way.)I don’t know how sweet I was; perhaps I was “balky” because the road was so hard. Landscape certainly shaped my experience.As I wrote about the pilgrimage in my diary then, “We went to another Hotel and walked. We went and had lunch at the Boggly [booglie] place. We went to a nother hotel called The Swan with fether Quits [quilts]. We went to the Queens head. We went to the Gest house. We went to aother Hotle called Srping wells and my tooth came out. We saw some taekeys [turkeys].” The repetition suggests how pilgrimage combines various aspects of life, from the emotional to the physical, the quotidian (walking and especially resting—in hotels with quilts) with the extraordinary (newly sprung tooth or the appearance of turkeys). “[W]ayfaring abilities depend on an emotional connection to the environment” (Easterlin 261), whether that environment is modified by humans or even manmade, inhabited by human or nonhuman actors. How can one model an “ecological relationship between humans and nonhumans” in narrative (Rodriguez 368)? Rodriguez proposes a “model of reading as encounter [...] encountering fictional story worlds as potential models” (Rodriguez 368), just as my mother did with the Magic Taxi Cab story.Taxis proliferate in my childhood pilgrimage. My mother writes in 1966 in her diary of journeying along the Pilgrims’ Way to St. Martha’s on the Hill. “Susie was moaning and groaning under her pack and at one desperate uphill moment gasped out, ‘Let’s take a taxi!’ – our highborn lady as we call her. But we finally made it.” “Martha’s”, as I later learned, is a corruption of “Martyrs”, a natural linguistic decay that developed over the medieval period. Just as the vernacular textures pilgrimage poems in the fourteeth century, the common tongue in all its glorious variety seeps into even the quotidian modern pilgrim’s journey.Part of the delight of pilgrimage lies in the characters one meets and the languages they speak. In 1994, the only time my husband and I cheated on a strictly ambulatory sacred journey occurred when we opted to ride a bus for ten miles where walking would have been dangerous. When I ask the bus driver if a stop were ours, he replied, “I'll give you a shout, love.” As though in a P. G. Wodehouse novel, when our stop finally came, he cried out, “Cheerio, love” to me and “Cheerio, mate” to Jim.Language changes. Which is a good thing. If it didn’t, it would be dead, like those martyrs of old. Like Latin itself. Disentangling pilgrimage from language proves impossible. The healthy ecopoetics of languages meshes with the sustainable vibrancy of the land we traverse.“Nettles of remorse…”: Derek Walcott, The Bounty Once my father had to carry me past a particularly tough patch of nettles. As my mother tells it, we “went through orchards and along narrow woodland path with face-high nettles. Susie put a scarf over her face and I wore a poncho though it was sunny and we survived almost unscathed.” Certain moments get preserved by the camera. At age seven in a field outside of Wye, I am captured in my father’s slides surrounded by grain. At age thirty-five, I am captured in film by my husband in the same spot, in the identical pose, though now quite a bit taller than the grain. Three years later, as a mother, I in turn snap him with a backpack containing baby Sarah, grumpily gazing off over the fields.When I was seven, we took off from Detling. My mother writes, “set off along old Pilgrims’ Way. Road is paved now, but much the same as fifteen years ago. Saw sheep, lambs, and enjoyed lovely scenery. Sudden shower sent us all to a lunch spot under trees near Thurnham Court, where we huddled under ponchos and ate happily, watching the weather move across the valley. When the sun came to us, we continued on our way which was lovely, past sheep, etc., but all on hard paved road, alas. Susie was a good little walker, but moaned from time to time.”I seem to whimper and groan a lot on pilgrimage. One thing is clear: the physical aspects of walking for days affected my phenomenological response to our pilgrimage which we’d undertaken both as historical ritual, touristic nature hike, and what Wendell Berry calls a “secular pilgrimage” (402), where the walker seeks “the world of the Creation” (403) in a “return to the wilderness in order to be restored” (416). The materiality of my experience was key to how I perceived this journey as a spiritual, somatic, and emotional event. The link between pilgrimage and memory, between pilgrimage poetics and memorial methods, occupies my thoughts on pilgrimage. As Nancy Easterlin’s work on “cognitive ecocriticism” (“Cognitive” 257) contends, environmental knowledge is intimately tied in with memory (“Cognitive” 260). She writes: “The advantage of extensive environmental knowledge most surely precipitates the evolution of memory, necessary to sustain vast knowledge” (“Cognitive” 260). Even today I can recall snatches of moments from that trip when I was a child, including the telling of tales.Landscape not only changes the writer, but writing transforms the landscape and our interaction with it. As Valerie Allen suggests, “If the subject acts upon the environment, so does the environment upon the subject” (“When Things Break” 82). Indeed, we can understand the “road as a strategic point of interaction between human and environment” (Allen and Evans 26; see also Oram)—even, or especially, when that interaction causes pain and inflames blisters. My relationship with moleskin on my blasted and blistered toes made me intimately conscious of my body with every step taken on the pilgrimage route.As an adult, my boots on the way from Winchester to Canterbury pinched and squeezed, packed dirt acting upon them and, in turn, my feet. After taking the train home and upon arrival in London, we walked through Bloomsbury to our flat on Russell Square, passing by what I saw as a new, less religious, but no less beckoning shrine: The London Foot Hospital at Fitzroy Square.Now, sadly, it is closed. Where do pilgrims go for sole—and soul—care?Slow Walking as WayfindingAll pilgrimages come to an end, just as, in 1966, my mother writes of our our arrival at last in Canterbury:On into Canterbury past nice grassy cricket field, where we sat and ate chocolate bars while we watched white-flannelled cricketers at play. Past town gates to our Queen’s Head Inn, where we have the smallest, slantingest room in the world. Everything is askew and we’re planning to use our extra pillows to brace our feet so we won’t slide out of bed. Children have nice big room with 3 beds and are busy playing store with pounds and shillings [that’s very hard mathematics!]. After dinner, walked over to cathedral, where evensong was just ending. Walked back to hotel and into bed where we are now.Up to early breakfast, dashed to cathedral and looked up, up, up. After our sins were forgiven, we picked up our rucksacks and headed into London by train.This experience in 1966 varies slightly from the one in 1994. Jim and I walk through a long walkway of tall, slim trees arching over us, a green, lush and silent cloister, finally gaining our first view of Canterbury with me in a similar photo to one taken almost thirty years before. We make our way into the city through the West Gate, first passing by St. Dunstan’s Church where Henry II had put on penitential garb and later Sir Thomas More’s head was buried. Canterbury is like Coney Island in the Middle Ages and still is: men with dreadlocks and slinky didjeridoos, fire tossers, mobs of people, tourists. We go to Mercery Lane as all good pilgrims should and under the gate festooned with the green statue of Christ, arriving just in time for evensong.Imagining a medieval woman arriving here and listening to the service, I pray to God my gratefulness for us having arrived safely. I can understand the fifteenth-century pilgrim, Margery Kempe, screaming emotionally—maybe her feet hurt like mine. I’m on the verge of tears during the ceremony: so glad to be here safe, finally got here, my favorite service, my beloved husband. After the service, we pass on through the Quire to the spot where St. Thomas’s relic sanctuary was. People stare at a lit candle commemorating it. Tears well up in my eyes.I suppose some things have changed since the Middle Ages. One Friday in Canterbury with my children in 2003 has some parallels with earlier iterations. Seven-year-old Sarah and I go to evensong at the Cathedral. I tell her she has to be absolutely quiet or the Archbishop will chop off her head.She still has her head.Though the road has been paved, the view has remained virtually unaltered. Some aspects seem eternal—sheep, lambs, and stiles dotting the landscape. The grinding down of the pilgrimage path, reflecting the “slowness of flat ontology” (Yates 207), occurs over vast expanses of time. Similarly, Easterlin reflects on human and more than human vitalism: “Although an understanding of humans as wayfinders suggests a complex and dynamic interest on the part of humans in the environment, the surround itself is complex and dynamic and is frequently in a state of change as the individual or group moves through it” (Easterlin “Cognitive” 261). An image of my mother in the 1970s by a shady tree along the Pilgrims’ Way in England shows that the path is lower by 6 inches than the neighboring verge (Bright 4). We don’t see dirt evolving, because its changes occur so slowly. Only big time allows us to see transformative change.Memorial PilgrimageOddly, the erasure of self through duplication with a precursor occurred for me while reading W.G. Sebald’s pilgrimage novel, The Rings of Saturn. I had experienced my own pilgrimage to many of these same locations he immortalizes. I, too, had gone to Somerleyton Hall with my elderly mother, husband, and two children. My memories, sacred shrines pooling in familial history, are infused with synchronic reflection, medieval to contemporary—my parents’ periodic sojourns in Suffolk for years, leading me to love the very landscape Sebald treks across; sadness at my parents’ decline; hope in my children’s coming to add on to their memory palimpsest a layer devoted to this land, to this history, to this family.Then, the oddest coincidence from my reading pilgrimage. After visiting Dunwich Heath, Sebald comes to his friend, Michael, whose wife Anne relays a story about a local man hired as a pallbearer by the local undertaker in Westleton. This man, whose memory was famously bad, nevertheless reveled in the few lines allotted him in an outdoor performance of King Lear. After her relating this story, Sebald asks for a taxi (Sebald 188-9).This might all seem unremarkable to the average reader. Yet, “human wayfinders are richly aware of and responsive to environment, meaning both physical places and living beings, often at a level below consciousness” (Easterlin “Cognitive” 265). For me, with a connection to this area, I startled with recollection emerging from my subconscience. The pallbearer’s name in Sebald’s story was Mr Squirrel, the very same name of the taxi driver my parents—and we—had driven with many times. The same Mr Squirrel? How many Mr Squirrels can there be in this small part of Suffolk? Surely it must be the same family, related in a genetic encoding of memory. I run to my archives. And there, in my mother’s address book—itself a palimpsest of time with names and addressed scored through; pasted-in cards, names, and numbers; and looseleaf memoranda—there, on the first page under “S”, “Mr. Squirrel” in my mother’s unmistakable scribble. She also had inscribed his phone number and the village Saxmundum, seven miles from Westleton. His name had been crossed out. Had he died? Retired? I don’t know. Yet quick look online tells me Squirrell’s Taxis still exists, as it does in my memory.Making KinAfter accompanying a class on a bucolic section of England’s Pilgrims’ Way, seven miles from Wye to Charing, we ended up at a pub drinking a pint, with which all good pilgrimages should conclude. There, students asked me why I became a medievalist who studies pilgrimage. Only after the publication of my first book on women pilgrims did I realize that the origin of my scholarly, long fascination with pilgrimage, blossoming into my professional career, began when I was seven years old along the way to Canterbury. The seeds of that pilgrimage when I was so young bore fruit and flowers decades later.One story illustrates Michel Serres’s point that we should not aim to appropriate the world, but merely act as temporary tenants (Serres 72-3). On pilgrimage in 1966 as a child, I had a penchant for ant spiders. That was not the only insect who took my heart. My mother shares how “Susie found a beetle up on the hill today and put him in the cheese box. Jimmy put holes in the top for him. She named him Alexander Beetle and really became very fond of him. After supper, we set him free in the garden here, with appropriate ceremony and a few over-dramatic tears of farewell.” He clearly made a great impression on me. I yearn for him today, that beetle in the cheese box. Though I tried to smuggle nature as contraband, I ultimately had to set him free.Passing through cities, landscape, forests, over seas and on roads, wandering by fields and vegetable patches, under a sky lit both by sun and moon, the pilgrim—even when in a group of fellow pilgrims—in her lonesome exercise endeavors to realize Serres’ ideal of the tenant inhabitant of earth. Nevertheless, we, as physical pilgrims, inevitably leave our traces through photos immortalizing the journey, trash left by the wayside, even excretions discretely deposited behind a convenient bush. Or a beetle who can tell the story of his adventure—or terror—at being ensconced for a time in a cheese box.On one notorious day of painful feet, my husband and I arrived in Otford, only to find the pub was still closed. Finally, it became time for dinner. We sat outside, me with feet ensconced in shoes blessedly inert and unmoving, as the server brought out our salads. The salad cream, white and viscous, was presented in an elegantly curved silver dish. Then Jim began to pick at the salad cream with his fork. Patiently, tenderly, he endeavored to assist a little bug who had gotten trapped in the gooey sauce. Every attempt seemed doomed to failure. The tiny creature kept falling back into the gloppy substance. Undaunted, Jim compassionately ministered to our companion. Finally, the little insect flew off, free to continue its own pilgrimage, which had intersected with ours in a tiny moment of affinity. Such moments of “making kin” work, according to Donna Haraway, as “life-saving strateg[ies] for the Anthropocene” (Oppermann 3, qtd. in Haraway 160).How can narrative avoid the anthropocentric centre of writing, which is inevitable given the human generator of such a piece? While words are a human invention, nonhuman entities vitally enact memory. The very Downs we walked along were created in the Cretaceous period at least seventy million years ago. The petrol propelling the magic taxi cab was distilled from organic bodies dating back millions of years. Jurassic limestone from the Bathonian Age almost two hundred million years ago constitutes the Caen stone quarried for building Canterbury Cathedral, while its Purbeck marble from Dorset dates from the Cretaceous period. Walking on pilgrimage propels me through a past millions—billions—of eons into the past, dwarfing my speck of existence. Yet, “if we wish to cross the darkness which separates us from [the past] we must lay down a little plank of words and step delicately over it” (Barfield 23). Elias Amidon asks us to consider how “the ground we dig into and walk upon is sacred. It is sacred because it makes us neighbors to each other, whether we like it or not. Tell this story” (Amidon 42). And, so, I have.We are winding down. Time has passed since that first pilgrimage of mine at seven years old. Yet now, here, I still put on my red plaid wollen jumper and jacket, crisp white button-up shirt, grey knee socks, and stout red walking shoes. Slinging on my rucksack, I take my mother’s hand.I’m ready to take my first step.We continue our pilgrimage, together.ReferencesAllen, Valerie. “When Things Break: Mending Rroads, Being Social.” Roadworks: Medieval Britain, Medieval Roads. Eds. Valerie Allen and Ruth Evans. Manchester: Manchester UP, 2016.———, and Ruth Evans. Introduction. Roadworks: Medieval Britain, Medieval Roads. Eds. Valerie Allen and Ruth Evans. Manchester: Manchester UP, 2016.Alworth, David J. Site Reading: Fiction, Art, Social Form. Princeton: Princeton UP, 2016.Amidon, Elias. “Digging In.” Dirt: A Love Story. Ed. Barbara Richardson. Lebanon, NH: ForeEdge, 2015.Barfield, Owen. History in English Words. Grand Rapids: William B. 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