Wound Rotor Motors

[boomer957]

Wondering how you can start a WRM W/O the Strating Resistors racked in and not burn up the rotor windings?

 

[DougMSOE]

You are correct! Most WRIM do not have the necessary rotor reactance to limit the stator current. You may get lucky but it is NOT a good idea.

 

[boomer957]

Doug,

Thanks, I was very sure that this was the case. I pulled the string on this matter and found out that they are opening a valve upstream of this pump/motor and allowing it to free wheel on system pressure prior to starting the motor. This limlits the "locked rotor" inrush current.

While I still believe that this is a very risky practice it seems to be allowing the start of these WRM's.

Wierd huh.

Rob Coffee
Allied Services Group

 

[jbartos]

Suggestion: If the motor shaft load torque-speed curve permits, use a suitable soft starting arrangement.