Pole Changing Method

Pole Changing Method is one of the main methods of the speed control of an induction motor. This method of controlling the speed by pole changing is used mainly for cage motor only because the cage rotor automatically develops a number of poles, which is equal to the poles of the stator winding. The number …

Pole Changing Method Read More »

Cogging in Induction Motor

The phenomenon of Magnetic Locking between the stator and the rotor teeth is called Cogging or Teeth Locking. Even after applying full voltage to the stator winding, the rotor of a 3 phase induction motor fails to start. This condition arises when the number of stator and rotor slots are either equal or have an …

Cogging in Induction Motor Read More »

Deep Bar Rotor

The Deep Bar Rotor in an induction motor is used to obtain high rotor resistance at starting and low rotor resistance at the running condition. The figure below shows a deep bar cage rotor with deep and narrow bars: A bar may be assumed to be made up of a number of narrow layers connected …

Deep Bar Rotor Read More »

No Load Test of an Induction Motor

No Load Test is an indirect method used for determining the efficiency and also to determine the circuit parameters of the equivalent circuit of the three-phase induction motors. The open-circuit test is performed on the transformer. The no-load test is the same as the open-circuit test performed on the transformer. In this method, the motor …

No Load Test of an Induction Motor Read More »

Starting of an Induction Motor

A three-phase Induction Motor is Self Starting. When the supply is connected to the stator of a three-phase induction motor, a rotating magnetic field is produced, and the rotor begins rotating and the induction motor starts. At the time of starting, the motor slip is unity, and the starting current is very large. The purpose …

Starting of an Induction Motor Read More »