Current data of transient anlysis in MAXWELL for 3-Phase induction motor

- February 1, 2020 at 8:10 am
  
  ranjanpal999
  Subscriber
  
  Hi,
  
  I have simulated a motor using 24 rotor bars with supply frequency of 50Hz in ANSYS MAXWELL.
  
  I have taken compete 360 degree model.
  
  In the FFT of motor current, data taken between 0.6sec-1sec, I can see some traces of PSHs at 1144 Hz and 1244 Hz respectively as shown in fig below.
  
  However, why don't we get to see a peak at 150Hz which is 3rd harmonic of line frequency?
  
  Though, in an experimental set-up, we do find all the odd harmonics of supply line frequency.
  
  Can anyone please comment of this!
- February 3, 2020 at 3:52 pm
  
  Paul Larsen
  Ansys Employee
  
  My guess is that you are using a Wye connected 3-phase motor, is that correct? 3rd harmonic is often involved with the neutral point connection and possibly capacitance to ground. The simulation model most likely uses an ideal Wye-connection so that there is no 3rd harmonic. If you want to see additional 3rd harmonic, you can try either of the following things:
  
  - Simply remove the Wye Connection. This means that each phase of the motor is separate, you can have zero-sequence currents.
  
  - Change to external circuit, and apply an impedance at the neutral point connection.
- February 4, 2020 at 5:08 am
  
  ranjanpal999
  Subscriber
  
  You are absolutely right.
  
  It's a Wye connection.
  
  For solution 1 as you mentioned, I am unable to find the suitable tab/menu to remove this Wye connection. Should I use delta connection in RMXpert and then move ahead with MAXWELL 2D analysis ?
  
  However, since the physical/experimental motor is Y-connected, hence I want to carry out the FEM simulation in Y only and not go for DELTA
  
  For Solution 2, I followed the steps as mentioned in this below image file:
  
  Could you please kindly help me out with this!