Red Seal Electrician Practice
MotorsQuestion 348 of 1506

A motor takes 8,500 W from the supply and delivers 7,500 W at the shaft. What is its efficiency?

  1. 12 %
  2. 113 %
  3. 0.88 %
  4. 88 %
Show answer

Correct answer: 88 %

Efficiency = (output ÷ input) × 100 = (7,500 ÷ 8,500) × 100, about 88 %.

Source: Troubleshooting Motors and Controls (Dickson-Self), 6.1: Testing Motor Components

Practice motors

Questions last reviewed: 18 October 2026