For a 3-phase, 4-pole, 50 Hz synchronous motor the frequency, pole number and the load torque are all halved. The motor speed will be
A. 375 rpm.
B. 75 rpm.
C. 1,500 rpm.
D. 3,000 rpm. [A.M.I.E. Electrical Science Winter 1993]
Answer:C
For a 3-phase, 4-pole, 50 Hz synchronous motor the frequency, pole number and the load torque are all halved. The motor speed will be
A. 375 rpm. B. 75 rpm. C. 1,500 rpm. D. 3,000 rpm. [A.M.I.E. Electrical Science Winter 1993]