Squirrel Cage Induction Motor

October 11, 2024 Post a Comment

Squirrel cage induction motor

Squirrel cage motors are a subclass of induction motors, which harness electromagnetism to generate motion. They are so-called “squirrel cage” motors because the shape of their rotor – the inner component connected to the output shaft – looks like a cage.

How does a squirrel cage motor work?

The field windings in the stator of an induction motor set up a rotating magnetic field through the rotor. The relative motion between this field and the rotation of the rotor induces electric current in the conductive bars.

What is difference between squirrel cage and induction motor?

The slip ring induction motors have high starting torque with low starting current whereas squirrel cage motors have low starting torque and high starting current. Slip-ring motor has smooth acceleration under heavy loads as compare to the squirrel cage motor.

What is 3 phase squirrel cage induction?

A 3 phase squirrel cage induction motor is a type of three-phase induction motor which functions based on Faraday's law of electromagnetic induction. It is called a 'squirrel cage' motor because the rotor inside of it – known as a 'squirrel cage rotor' – looks like a squirrel cage.

What type of motor is a squirrel cage motor?

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.

What is induction motor working principle?

Working Principle of Induction Motor The electromagnetic induction is the phenomenon in which the electromotive force induces across the electrical conductor when it is placed in a rotating magnetic field. When the three phase supply is given to the stator, the rotating magnetic field produced on it.

Where is squirrel cage motor used?

These motors are commonly used in: Centrifugal pumps. Industrial drives (e.g. to run conveyor belts) Large blowers and fans.

What are the advantages of cage motor?

Squirrel Cage Induction motors are cheaper in cost compared to Slip Ring Induction motors. Requires less maintenance and rugged construction. Because of the absence of slip rings, brushes maintenance duration and cost associated with the wear and tear of brushes are minimized.

Is squirrel cage motor synchronous?

A synchronous motor may have a squirrel-cage winding embedded in its rotor, used to increase the motor starting torque and so decrease the time to accelerate to synchronous speed. The squirrel cage winding of a synchronous machine will generally be smaller than for an induction machine of similar rating.

What is slip speed and slip frequency?

The difference between the synchronous speed of the electric motor magnetic field, and the shaft rotating speed is slip - measured in RPM or frequency.

What are the types of induction motor?

There are three basic types of small induction motors: split-phase single-phase, shaded-pole single-phase, and polyphase. In two-pole single-phase motors, the torque goes to zero at 100% slip (zero speed), so these require alterations to the stator such as shaded-poles to provide starting torque.

What is torque of motor?

Torque: The torque output of a motor is the amount of rotational force that the motor develops. The torque of a small electric motor is commonly measured in either inch pounds (in-lbs), Newton meters (N-m) or other directly converted units of measure.

How does a 3-phase squirrel cage motor work?

Squirrel induction motor working is based on the principle of electromagnetism. When the stator winding is supplied with a three-phase AC, it produces a rotating magnetic field (RMF) which has a speed called synchronous speed. This RMF causes voltage induced in the rotor bars.

What is cogging and crawling?

The phenomenon of cogging and crawling of induction motor happens due to improper motor design or operating the motor by feeding the harmonic rich supply source. In the case of cogging of induction motor, the motor does not accelerate at all and it gets stalled. The cogging phenomenon is also called magnetic locking.

What is working principle of 3-phase induction motor?

Therefore, the working principle of a 3-phase induction motor is fundamentally based on electromagnetic induction. The RMF passes through air gap and cuts the rotor conductors, which are stationary at start. Due to relative motion between RMF and the stationary rotor, an EMF is induced in the rotor conductors.

Why squirrel cage rotor is short circuited?

Why are squirrel cage rotor ends short circuited? Current requires a closed path to flow. Hence, the ends are short circuited so that the induced current can flow through it and produce required magnetic flux in order to rotate.

Who invented the squirrel cage induction motor?

Dolivo-Dobrowolsky built the first simple, practically useful three-phase induction motor with squirrel cage rotor.

What is the starting torque of a squirrel cage induction motor?

Starting Torque of Squirrel Cage Motors – For the squirrel cage motors, the starting torque is very low about 1.5 to 2 times of the full-load value. Starting Torque of Wound Rotor Motors – In case of slip ring induction motors, the resistance of the rotor circuit can be increased by inserting external resistance.

Are induction motors AC or DC?

Induction motors, linear motors, and synchronous motors, for example, are all types of AC motors. AC motors can also include variable-frequency drives to control the motor's speed and torque, while DC motors are available in self-excited and separately excited-type models.

Why is it called 3-phase induction motor?

The asynchronous nature of induction motors creates slip—the difference between the rotating speed of the shaft and the speed of the motor's magnetic field—which allows for increased torque. These motors are powered at the stator, while the rotor induces current—hence the name “induction” motor.