These results were produced using v1.0.3.1 (February 10-25, 2007).
FEA of 12 slot, 4 pole motor
This example shows the results using a 12 slot, 4 pole motor in a 45 step multirun. The rotor is rotated 90 mechanical (180 electrical) degrees in steps of 2 degrees. A comparison is made between the results obtained by analytical calculations and finite-element analysis. |
There is no skew in the stator and breadloaf magnets are used for the rotor poles. The motor was modeled as a full motor without taking advantage of the symmetry. The mesh consisted of 7244 elements. A reusable mesh was generated. A single air gap layer was used. The FEA results appear to be lower than the analytical calculations as the end effects are not considered in the 2-D analysis. The electromagnetic torque computed includes the cogging torque. All calculations and analysis were performed on a PC with a 2.1 GHz AMD X2 dual core processor. A total of 46 steps were calculated in 2 parallel threads simultaneously. The torque was calculated using Maxwell's stress method. The wye and delta simulations had different number of turns and rotational rotor speed. More accurate results can be obtained by increasing the mesh density and the number of steps.
Delta connection
The winding is Delta connected and is a standard winding for a 12 slot, 4 pole motor with a span of 3 slots. The current into the motor is not limited peak by PWM current limiting. The phase currents are shown below.
Phase currents in the three phase Delta winding
First Order
Rated torque calculated by analytical calculations for 1/2 electrical cycle |
Rated torque calculated by first order FEA for 1/2 electrical cycle |
Air gap flux density calculated analytically and by FEA
First order calculations took a total of 2.88 minutes. The actual time is approximately one half as there were two parallel threads used. Mesh contained 3649 nodes.
Second Order
Rated torque calculated by analytical calculations for 1/2 electrical cycle |
Rated torque calculated by second order FEA for 1/2 electrical cycle |
Air gap flux density calculated analytically and by FEA
Second order calculations took a total of 93.34 minutes. The actual time is approximately one half as there were two parallel threads used. Mesh contained 14541 nodes.
Third Order
Rated torque calculated by analytical calculations for 1/2 electrical cycle |
Rated torque calculated by third order FEA for 1/2 electrical cycle |
Air gap flux density calculated analytically and by FEA (at zero rotor position)
Third order calculations took a total of 513.6 minutes. The actual time is approximately one half as there were two parallel threads used. Mesh contained 32677 nodes.
Wye connection
The winding is Wye connected and is again a standard winding for a 12 slot, 4 pole motor with a span of 3 slots. The phase currents are shown below.
Phase currents in the three phase Delta winding
First Order
Rated torque calculated by analytical calculations for 1/2 electrical cycle |
Rated torque calculated by first order FEA for 1/2 electrical cycle |
First order calculations took a total of 5.06 minutes. The actual time is approximately one half as there were two parallel threads used. Mesh contained 3649 nodes.
Second Order
Rated torque calculated by analytical calculations for 1/2 electrical cycle |
Rated torque calculated by second order FEA for 1/2 electrical cycle |
Second order calculations took a total of 95.88 minutes. The actual time is approximately one half as there were two parallel threads used. Mesh contained 14541 nodes.