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Single-phase Induction Motor (T.E.A.M. Problem 30B)

Motors and generators with MagNet

Presented is a half-model of a single-phase induction motor which has a periodic boundary condition on the plane of symmetry. It was simulated using the MagNet transient 2d with motion solver in a single transient run, as a velocity-driven problem.

The velocity was specified as a staircase function spending 100ms at each speed, enough time for the transients to die out. The time step size varied from 1 ms per time step during the first 80 ms at each speed to 0.25 ms per time step during the last 20 ms at each speed. The average torque was calculated from the transient waveforms in the last 20 ms at each speed.

The following is based on the Testing Electromagnetic Analysis Methods (T.E.A.M.) problem #30B: Analytic Analysis of Single and Three Phase Induction Motors. The benchmark can be found on the International Compumag Society's website.

TEAM Workshop Problem 30B - Single-phase induction machine

METHODS and RESULTS

COMPARING MAGNET'S RESULTS to the ANALYTICAL RESULTS

The average torque at different speeds from zero to synchronous speed (blue trace), compared to the analytic results (red trace).

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RIPPLE TORQUE

The ripple torque, which close to synchronous speed, is larger than the average torque. This implies that during part of the cycle the magnetic forces work against the rotor motion.

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