Due to the fringing effect, magnetic flux in the air gap of electrical machines is reduced. This leads to enlarged effective air gap length. Currently, the Carter coefficient is applied to compensate the slot effects. This coefficient is calculated with respect to the slot dimensions and air gap length, using Carter formulas and corresponding curves. These curves are taken by solving the two.
ZHU AND HOWE: INFLUENCE OF DESIGN PARAMETERS ON COGGING TORQUE IN PERMANENT MAGNET MACHINES 409 Fig. 5. Variation of peak cogging torque with slot number in 2-pole motor. TABLE II FACTOR C FOR TYPICAL 2-POLE BRUSHED PM MOTORS with overlapping windings all edges of magnets would face slot openings. Fig. 5 shows the variation of the peak cogging.
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The use of slotted stator permanent-magnet machines with concentrated windings is increasing in industry. In this paper, the effect of the slot opening on flux linkage, internal voltage, mean torque, rotor eddy current loss and stator iron losses is evaluated. This gives new insight into the influence of slotting on the performance of machines with a small slot opening. In addition, the slot.
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It covers the investigation of the effect of stator-slot and rotor-pole number combinations for surface-mounted PM (SPM) machines, and the stator-slot and rotor-effective-slot number combinations for interior permanent magnet (IPM) machines. The effect of changing the number of slots and poles on the performance of a particular SPM machine design is studied in detail using finite element.
One can see that the maximum noise at variable speed no-load, which is dominated by a zero-th wavenumber, is minimized close to one stator slot pitch. The optimal skew angle depends on the type of the force wave responsible for noise and depends on the load condition, so the optimal skew rate is not always one slot pitch.
The effects of PMs in the stator slot openings are comparatively investigated for VFRMs, HESSPMs and SSPMs together with the discussion of the unique fault tolerant feature in stator slot PM machines. Furthermore, the overlapping winding (OW) layouts with coil pitches of 3 stator slot pitches are proposed in the three machine topologies in order to enhance the torque density. The.
This paper address the effect of magnet coverage on the torque, iron and magnet loss components and torque ripple of two surface permanent magnet synchronous generators of 5MW. The values of torque, torque ripple, iron and magnet losses are calculated using a FEM program. It is concluded that the optimal magnet coverage can only be found by extensive investigations for each specific machine.
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Two kind of nonuniform slot distribution models, the unit machine shift model (Model 1) and the single slot shift model (Model 2), are proposed for reducing cogging torque of surface-mounted permanent magnet (SPM) machines. Further, based on exact su.
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Permanent magnet lodestones contain magnetite, a hard, crystalline iron ferrite mineral that derives its magnetism from the effect the earth's magnetic field has on it. Various steel alloys can also be magnetized. The first big step in developing more effective permanent magnet materials came in the 1930s with the development of Alnico alloy magnets. These magnets take their name from the.
Design and Analysis of a New Dual-Stator Permanent-Magnet Machine for Direct-Drive Applications S. L. Ho, Shuangxia Niu and W. N. Fu The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong By virtue of their high torque density, double-stator permanent magnet (PM) electric machines can be effectively used for low-speed, direct-drive applications. In this paper, a new magnetic gear.
The performance of fault-tolerant modular permanent magnet machines depends on the proper selection of the pole and slot numbers which result in negligible coupling between phases. The preferred slot and pole number combinations eliminate the effect of low-order harmonics in the stator magnetomotive force and thereby the vibration and stray loss are reduced. In this paper, three external rotor.
In the presented work, influence of magnet shaping on cogging torque of surface-mounted Permanent Magnet PM machines is investigated. The considered PM shape for the magnet shaping is the loaf-shape PM with off-set arcs. For the first time, based on the solution of the Poissons's equation, an analytical model is provided to predict the magnetic flux density of the slotted-armature and surface.
IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 32, NO. 1, MARCH 2017 111 Applicability of Fractional Slot Axial Flux Permanent Magnet Synchronous Machines in the.
Fig.3 shows the effect on torque ripple of changes in the slot opening. Setting the slot opening bg and the tooth pitch rs to an ap-propriate ratio (0.25 in the example shown in s p h1 h2 bg dw Permanent magnet Tooth Fig. 2 Typical design parameters for concentrated-winding motors Fig. 3 Electric current-torque ripple characteristics (as a.
A Computationally Efficient PM Power Loss. predictions from the FE analyses are then used to define a functional representation which accounts for the temperature effect of the magnet loss by incorporating a temperature correction. The proposed method has been validated on two surface-mounted brushless AC PM machine designs showing good agreement with direct FE predictions of the PM power.