# What is rotating magnetic field in induction motor?

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A rotating magnetic field is a magnetic field that has moving polarities in which its opposite poles rotate about a central point or axis. … Rotating magnetic fields are often utilized for electromechanical applications, such as induction motors and electric generators.

## What is rotating magnetic field in 3 phase induction?

When we apply a three-phase supply to a three-phase distributed winding of a rotating machine, a rotating magnetic field is produced which rotates in synchronous speed. … This is a similar representation of current is a three-phase system as the flux is cophasial with the current.

## What creates a rotating magnetic field in an induction motor?

The rotating magnetic field is produced by the three-phase current of the stator in the actual three-phase induction motor. … The three-phase windings of the inner stator are spaced 120° electrical degrees apart. In addition, the conductor of each winding is distributed such as a sinusoidal wave.

## What is the speed of rotating magnetic field?

Speed is important to the rotating magnetic field of an AC motor. It is known as “synchronous speed.” This speed is calculated by dividing 120 times the frequency (F) by the number of poles (P). As an example, the synchronous speed for a 2-pole motor operated at 60 Hz is 3,600 RPM.

## How does the rotor rotates in induction motor?

In a three-phase induction machine, alternating current supplied to the stator windings energizes it to create a rotating magnetic flux. … The rotor circuit is shorted and current flows in the rotor conductors. The action of the rotating flux and the current produces a force that generates a torque to start the motor.

## What do you mean by rotating magnetic field?

A rotating magnetic field is a magnetic field that has moving polarities in which its opposite poles rotate about a central point or axis. … Rotating magnetic fields are often utilized for electromechanical applications, such as induction motors and electric generators.

## What is slip speed?

The speed at which the induction motor work is known as the slip speed. … The difference between the synchronous speed and the actual speed of the rotor is known as the slip speed. In other words, the slip speed shows the relative speed of the rotor concerning the speed of the field.

## What are the advantages of rotating magnetic field?

• Rotating field type alternator is used in big power plants because of its high power rating.
• As the armature is stationary power can be get without using brush or slip rings.
• We can insulate the conductor as the armature is stationary.
• Insulation can be kept high in fixed armature type alternator.

## How is rotation caused in a motor?

When an electric current flows through the coil, a force is exerted on the coil, causing it to spin. … the current is turned on and off at the correct time so the magnetic field of the wire interacts with that of the two magnets. this makes the coil rotate.

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## When a motor is short circuited what causes the motor to still rotate?

A magnetic field with the poles facing out is produced in the rotor due to the stator induced current. This causes the rotor (motor shaft) to rotate. As long as the stator is supplied to a stable voltage supply, the motor shaft will continue to rotate. During a short circuit condition the system voltage will decay.

## What is 120 in motor speed formula?

The equation for calculating synchronous speed is: S = 120 f/P speed = constant (120) times frequency of power source (60 Hz) divided by number of poles used in the motor (P). Where does the 120 come from and what units does it have? There is RPM on one side and Cycles/second divided by #of poles on the other.

## What is asynchronous speed?

The asynchronous motor name suggests that the rotor speed is asynchronous with the rotational speed of the stator magnetic field. To be exact, the rotor of asynchronous motor rotates with a relatively lesser speed than the stator RMF.

## What is synchronous speed?

Synchronous speed is a significant parameter for the rotating magnetic field-type AC motor. It is determined by the frequency and the number of magnetic poles. Synchronous speed No = [rps, revolutions per second] f = Frequency [Hz]

## Can induction motor run at synchronous speed?

The induction motor can not run at synchronous speed because synchronous speed is a hypothetical speed not a rela speed.21 мая 2018 г.

## How does an induction motor start?

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

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## Why starter is used in induction motor?

The three phase induction motors are self-starting due to rotating magnetic field. But the motors show tendency to draw very high current at the time of starting. … Hence there should be a device which can limit such high starting current. Such a device which limits high starting current is called a starter.11 мая 2017 г. 