Red Seal Electrician Practice
MotorsQuestion 1207 of 1506

A small synchronous motor has 5 pairs of N-S poles and runs on 50 Hz power. What is its speed?

  1. 3000 rpm
  2. 600 rpm
  3. 300 rpm
  4. 6000 rpm
Show answer

Correct answer: 600 rpm

The rotor turns once for every 5 cycles. 50 / 5 = 10 rotations per second, which is 600 rpm.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 13.2: Synchronous Motors

Practice motors

Questions last reviewed: 18 October 2026