Application Examples - Induction Motors

Application examples with Model Files available
Three-phase induction motor startup
Single-phase induction motor
Accurately modelling the skewed rotor of an induction motor
Axial flux disk induction machine
Three-phase induction motor startup (TEAM Problem 30A)
This is an example of a three-phase induction motor. In MagNet, this IM is simulated and analysed using the Transient 2D with Motion solver. The method and results presented here displays the characteristics of the machine during startup. In this analysis, no load or friction is specified.

The following is based on the Testing Electromagnetic Analysis Methods (TEAM) Problem 30A: Induction Motor Analyses. The benchmark can be found on the International Compumag Society's website (TEAM Problems).

Open Report (Model 0035)

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Single-phase induction motor (TEAM Problem 30B)
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 following is based on the Testing Electromagnetic Analysis Methods (TEAM) Problem 30B: Analytic Analysis of Single and Three Phase Induction Motors. The benchmark can be found on the International Compumag Society's website (TEAM Problems).

Open Report (Model 0040)

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Accurately modelling the skewed rotor of an induction motor
Induction motors are one of MagNet's specialities. The induction motor analysed here is a typical three-phase motor, but MagNet modelling improvements have made it easy to include features that were previously ignored. The rotors of induction motors often have skewed slots to minimize torque ripple; this is now easily created and accurately modelled.

Open Report (Model 0053)

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Axial flux disk induction machine
View the capabilities of the 3D Transient with Motion solver in a unique and truly 3D machine--an axial flux disk induction machine. The flux flows parallel to the axis of the rotor. Currents are induced in a flat disc-shaped aluminium rotor element. The 3D Transient with Motion solver was used to model both a run-up to synchronous speed and also to create a torque-speed curve. This particular machine (built and tested by the University of Bath, UK) provided the opportunity to compare the MagNet results against measurements made on the real device, and to also show the accuracy and value of simulation with MagNet.

Open Report (Model 0113)

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Application Examples - Induction Motors
Other application examples (report only)
Simulating a skewed induction machine in 2D
Reducing the start-up transients of an induction motor
Simulating a skewed induction machine in 2D
Induction motors often have skewed rotor bars in order to minimize the torque ripple and cogging effect. Skewing also eliminates high-order harmonics in the stator current waveform which can potentially be harmful. By definition, skewing is a three-dimensional feature and usually requires lengthy 3D simulations. Fortunately, MagNet's unique mesh capabilities make it possible to accurately model skew using the powerful 2D solver and a multi-slice approach. The key point is that a number of slices of the machine need to be solved in parallel in order to obtain the right induced currents in the rotor bars. This approach is implemented in the time domain analysis presented here. The transient with motion solver is first used to study high-order harmonics in the stator current waveform at constant speed and then to simulate load driven operation with an applied external load.

Open Report (Model 0194)

Reducing the start-up transients of an induction motor
The steady-state characteristics of devices with periodic excitations – such as motors and generators – are often of interest. Unfortunately, the large time constants can have start-up transients that take a considerable amount of time to die out. One example is voltage-driven coils with large inductances.

The start-up response cannot be skipped by simply starting the simulation at a later time. However, there is no need to wait through the slow start-up response either.

There are a number of techniques to significantly reduce the duration of start-up transients using the right initial conditions with MagNet. These powerful features are applied to the simulation of an induction machine. These methods can all be automated by scripting as well.

Open Report (Model 0198)