A three-phase induction motor has been tested, and has small stator resistance. At 230 V, 60 Hz, the motor produces 40 N-m at 1740 RPM.
a) Given a 40 N-m load, input of 115 V and 30 Hz, what operating speed do you expect?
b) This machine is operated as a variable-speed generator. The external drive imposes 20 N-m on the shaft. The speed is 2400 RPM. Determine the appropriate operating frequency and voltage. What if the speed is 1880 RPM?