Explanation: Fr is not fixed in synchronous and induction machine. 9. In all rotating electrical machine, electrical torque is developed when relative speed between stator field and rotor field is ____________
A. zero
B. equal to rotor speed
C. equal and opposite to rotor speed
D. dependent upon the type of electrical machine
Answer:A
Explanation: Fr is not fixed in synchronous and induction machine. 9. In all rotating electrical machine, electrical torque is developed when relative speed between stator field and rotor field is ____________
A. zero B. equal to rotor speed C. equal and opposite to rotor speed D. dependent upon the type of electrical machine
Explanation: If the relative speed between stator field and rotor field is not zero, then the load angle δr varies with time.