What is the typical slip percentage for a standard induction motor?

• A. 0%
• B. 2-5%
• C. 5-10%
• D. 10-15%

Answer: (B)

In an induction motor, torque comes from the rotor lagging behind the stator’s rotating magnetic field. This lag, called slip, is the difference between the synchronous speed and the rotor speed, expressed as a percentage of the synchronous speed. At start, slip is 100% because the rotor is stationary; once running under normal load, the rotor speeds up and the slip settles to a small value that provides the necessary torque.

For a standard induction motor at rated load, that slip is typically in the 2 to 5 percent range. If slip were 0%, no torque would be produced; if it were much higher, the motor would operate with poorer efficiency and heat buildup. So the typical slip percentage is about 2-5 percent.