How Do You Start A Wound Rotor Motor With The Secondary Shorted?
I have been asked many times if a wound rotor induction motor can be started with the slip rings shorted. The reasons to do this can be anything from an emergency situation such as to move a crane with a load suspended in a congested are to saw where the owner is placing a variable frequency drive but does not want to replace the motor due to other considerations. Determine if the motor can be started with the slip rings shorted. Most often if the motor is under 50 HP the answer is yes. Motors above 50 HP may or may not be started with the slip rings shorted. When in doubt consult with the motor manufacturer, they may have specific recommendations. You may have to install a permanent slip resistor across the secondary leads instead of a direct short. Determine where you are going to short the leads on the wound rotor induction motor. It has been my experience that it is better to short the leads of the motor leaving as much wire as possible between the slip rings and the short as possi
