1,720,982 research outputs found
Simple method for calculating the peak torque of a switched reluctance motor: a computational investigation
No full textMagnetic field and force characteristics of a solenoid actuator for display board application
No full textGeneric field problems in design studies of high temperature superconducting transformers
No full textComputation of no-load electromagnetic rotor losses in high-speed permanent-magnet machines
No full textPerformance and design optimisation of electric motors with heteropolar surface magnets and homopolar windings
No full textElectric motors that embody heteropolar arrays of rotor magnets interacting with homopolar stator windings are capable of exceptionally high levels of torque per unit volume or mass. Design studies of the surface-magnet form of this class of machine have determined optimum values for the following ratios: C-core pitch/gap, magnet depth/gap, and C-core width/C-core pitch. The results are presented partly in the paper, which concentrates on three-dimensional computational design studies and on physical discussion of behaviour, and partly in a companion paper, which concentrates on theory of performance and figures of merit for design
The problem of power factor in VRPM (transverse-flux) machines
No full textThe purpose of the paper is to explore the theory of power factor in variable reluctance permanent magnet (VRPM) machines and to understand what physical features of these machines tend to cause the low value. A single figure of merit, for a given design, is identified that effectively determines what the best available working power factor may be. The same figure of merit is applicable to synchronous machines of conventional configuration, so that comparison can be made between VRPM and conventional machines and the fundamental reasons for their difference in working power factor understood. The scope for power factor improvement in VRPM machines can then be examined, by changing the electromagnetic design so as to modify the figure of merit appropriately. However, it will become clear that a very limited amount of improvement is possible, and low working power factor seems to be the price that must be paid for the high specific output
Comparison of alternative topologies for VRPM (transverse-flux) electrical machines
No full textThis paper is concerned with a comparison of relative advantages and disadvantages of three alternative topologies for the general class of electric motors in which stator windings excite an air gap magnetic field of one pole-number, which is then modulated by a toothed steel structure so as to enable interaction with a heteropolar field of different pole-number produced by an arrangement of rotor permanent magnets. Such machines are variously described as variable-reluctance permanent-magnet (VRPM) or transverse-flux. The tree alternative topologies considered are: single-sided surface-magnet, single-sided surface magnet with stator bridges, and double-sided flux-concentrated
Calculation of rotor eddy-current loss in high-speed PM alternators
No full textThis paper is concerned with the calculation of rotor eddy-current power losses in high-speed permanent magnet (PM) alternators. The work described covers the no-load tooth-ripple losses due to the distortion of the fundamental flux density wave by the stator slotting (making the flux density stronger under teeth and weaker under slots), and the on-load losses which include the additional effects of the MMF winding harmonics, including particularly the important slot order harmonics. Significant eddy-current losses may occur in the magnet material, in the steel hub underlying the magnets, and in the retaining sleeve over the magnets if that is conducting
Comparison of flux-concentrated and surface-magnet configurations of the VRPM (transverse-flux) machine
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