A Cascade method of speed control involves the use of two coupled induction motors.
The necessary condition for speed control is that
A. both the motors are of the wound rotor type having the same number of poles
B. both the motors are of the squirrel cage rotor type having different number of poles
C. one motor is of the slip-ring type but both the motors have the same number of poles
D. one motor is of the slip-ring type and the two motors have different number of poles
Show Answer
Answer: D
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