HV Exit Exam • Set 3 Question 29 of 30
In a 3-phase induction motor operating in normal motoring mode, the rotor rotates at a speed that is:
✓
Direct Answer
Option B: Slightly lower than the synchronous speed of the stator field
An induction motor requires relative motion (slip) between the rotating stator magnetic field and the rotor conductors to induce rotor current and develop torque. Hence, rotor speed is lower than synchronous speed.
All Options
A
Equal to the synchronous speed of the stator rotating magnetic field
B
Slightly lower than the synchronous speed of the stator field
(Correct Answer)
C
Higher than the synchronous speed of the stator field
D
Completely unrelated to the stator supply frequency
Detailed Explanation & Context
An induction motor requires relative motion (slip) between the rotating stator magnetic field and the rotor conductors to induce rotor current and develop torque. Hence, rotor speed is lower than synchronous speed.
Relevant Framework: STCW 2010 Manila Amendments • DG Shipping E-Learning & Exit Exam Standards • High Voltage Safety Officer & Switchgear Operations (HV).
Advertisement
Practice Full HV Set 3
Test yourself with 30 interactive questions, live timer, and instant score.