Squirrel Cage Induction Motor: Working Principle & Applications

A 3 phase squirrel cage induction motor is a type of three phase induction motor which functions based on the principle of electromagnetism. It is called a ‘squirrel cage’ motor because the rotor inside of it – known as a ‘squirrel cage rotor’ – looks like a squirrel cage. This rotor is a cylinder of … Read more

Starting of Three Phase Induction Motor

Let us consider the case of starting of a 3 phase inductor motor. Here, we apply a three-phase supply across the motor having three-phase stator winding. We arrange the stator winding in such a way that each phase is 120o separate from each other. This arrangement produces a revolving magnetic field in the stator due … Read more

Star Delta Starter

A star delta starter is the most commonly used method for the starting of a 3 phase induction motor. In star delta starting an induction motor is connected in through a star connection throughout the starting period. Then once the motor reaches the required speed, the motor is connected in through a delta connection. Here, … Read more

Direct Online Starter or DOL Starter

The most basic, inexpensive and straightforward method of starting a 3 phase squirrel cage induction motor is the DOL starter. Direct online starter (DOL) connects 3-phase motors directly across 3-phase supply, and the beauty of this type of starter is in spite of motor connected straight, it doesn’t cause any harm to the motor. Mainly … Read more

Starting Methods for Polyphase Induction Machine

In this article we are going to discuss various methods of starting a 3 phase induction motor. Before we discuss this, it is very essential here to recall the torque slip characteristic of the three phase induction motor which is given below. From the torque slip characteristic, it is clear that at the slip equals … Read more

Speed Control of Induction Motor Using Static Devices

In 1891 at the Frankfurt exhibition Nikola Tesla presented a crude type of poly phase induction motor. Induction motors are widely used. Nearly 80% of the world’s AC motors are poly phase induction motors. So speed control of this motor is an important agenda. The speed control of poly phase induction motor can be done … Read more

Deep Bar Double Cage Induction Motor

Generally in induction motor related operations, squirrel cage induction motors are widely used. The starting torque equation of an induction motor is given by Where, R2 and X2 are the rotor resistance and inductive reactance at starting respectively, E2 is the rotor induced EMF and Ns is the RPS speed of synchronous stator flux. Here in … Read more

Induction Motor Rotor

Rotor as the name suggests it is a rotating part of an electrical machine, in which current is induced by transformer action from rotating magnetic field. Induction motor rotor is of two types: Squirrel Cage Rotor Wound Type Rotor or Slip Ring Type Rotor Squirrel Cage Rotor In this type of rotor, the rotor winding … Read more

Torque Equation of Three Phase Induction Motor

The torque produced by three phase induction motor depends upon the following three factors: Firstly the magnitude of rotor current, secondly the flux which interact with the rotor of three phase induction motor and is responsible for producing emf in the rotor part of induction motor, lastly the power factor of rotor of the three … Read more

Three Phase Induction Motor Definition & Working Principle

An electrical motor is such an electromechanical device which converts electrical energy into a mechanical energy. In case of three phase AC operation, most widely used motor is Three phase induction motor as this type of motor does not require any starting device or we can say they are self-starting induction motors. For better understanding, … Read more