Yes, motor loads react differently.
The issue is, motor torque is reduced by the square of the voltage reduction. So if you end up with just a 20% voltage drop for whatever reason, you have 80% voltage and your motor output torque just dropped to .80 x .80 = 64% of rated torque! Since it isn't likely that the load changed, the lower torque allows the motor to slow down more, meaning increased slip. More slip means more current draw to try to regain speed. In the worst case, more current draw means more voltage drop, means more torque loss, means more slip, means more current, more voltage drop etc. etc. until the breaker or overload relay trips.
Last edited by jraef; 07/19/07 03:08 AM.
