Modeling Part-winding motor start
Modeling Part-winding motor start
(OP)
I'm trying to model expected voltage drop for starting a 200 hp motor using part-winding starter (not my idea).
I don't have a lot of experience with part-winding starting, but my understanding is that the main purpose is just to reduce the initial inrush current then quickly transition to the full winding to accelerate the motor.
So is it reasonable to assume that when the starter switches to full winding mode, the motor will be drawing close to locked-rotor current?
Thanks,
Dave
I don't have a lot of experience with part-winding starting, but my understanding is that the main purpose is just to reduce the initial inrush current then quickly transition to the full winding to accelerate the motor.
So is it reasonable to assume that when the starter switches to full winding mode, the motor will be drawing close to locked-rotor current?
Thanks,
Dave





RE: Modeling Part-winding motor start
And, yes, there will be a second inrush when making transition to the run winding. It's magnitude will be related to how far up the acceleration ramp the start winding was able to go.
RE: Modeling Part-winding motor start
My understanding is that the time on the part-winding is quite short - maybe l or 2 seconds?
RE: Modeling Part-winding motor start
The pitfall in modeling it is that the transition time MUST be short enough to make sure that you do not allow the motor to fall into the nadir of its Pull-Up torque, the dip in the torque-speed curve that occurs at 50% speed, at a time when the load torque requirements are greater than that value, otherwise you enter into a stall. So the transition time may end up being shorter and therefore the spike higher than you want it to be, but you will have no choice in the matter because there is nothing to adjust on the PW starter other than transition time.
RE: Modeling Part-winding motor start