Why the no load current of an induction motor is more than that of a transformer?

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As the air gap between the stator field winding and rotor winding is large, the more magnetizing current is needed to create flux which will cut the rotor conductor. … So it is an important reason why Induction Motor draws more No Load Current than a transformer.

Why the no load current of 3ph induction motor is more in of full load current as compared to no load current of 3ph transformer?

3. No load current in induction motor is 10-20% of full load current and the no load current of transformer is 2-6%. Explanation: The air gap in induction motor is more prominent than transformer and so the flux requirement will also be more. … The rated current in induction motor for a three phase system is 100A.

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Why the magnetizing current of an induction motor much higher than that of a transformer?

The magnetic circuit of the induction motor has an air gap and hence higher reluctance as compared to a transformer magnetic circuit having no air gap. In order to set up magnetic flux inside the air gap of induction motor, large magnetizing current is required.

Why no load current in a transformer is very low?

In the case of no-load, the secondary terminal of the transformer is open. There is no path available for the current to flow on the secondary side. Hence, the transformer does not draw current from the source.

Why does induction motor has high starting current?

This high current in the rotor will create its own magnetic field which opposes the main stator magnetic field, this weakens the stator magnetic field so the back EMF in the stator will drop and the supply voltage will be much higher than the stator back EMF and so the supply current increases to a high value.

When 3-phase induction motor is at no load the slip is?

Q1 A 3-phase, 6-pole, 50 Hz induction motor has a slip of 1% at no-load and 3% at full-load. Find (i) synchronous speed, (ii) no-load speed (iii) full-load sped (iv) frequency of rotor current at standstill (v) Frequency of rotor current at full-load.

The region (extending from s = sm to s = 1) is called unstable region. In this region with the increase in load, slip increases but torque decreases. The result is that the motor could not pick up the load and slows down and eventually stops.

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Why is the magnetizing reactance of induction motor much smaller than the one of the transformer?

The magnetizing current in the case of the induction motor is higher than the transformer because the air gap of the induction motor causes higher reluctance. The magnetizing reactance X in an induction motor will have a much smaller value.

What should be the no load current of an induction motor?

The magnetising current(Im) is drawn by an induction motor to set up the magnetic flux in the air gap. The magnetizing current is responsible for setting up air gap power in induction motor. … The no load current of induction motor varies fro 30 to 60 % of its full load current.

What is magnetizing current in induction motor?

The magnetization current im :The current required to produce the flux in the core of the transformer. 2. The core-loss current Ie :The current required to make up for the hysteresis and eddy current losses.

What is the purpose of no load current?

The primary purpose of the no load current is setting up of the magnetic flux. The flux produced in the primary winding travels through the magnetic core and gets linked to the secondary winding of the transformer.

If there is no load condition, no current flows and there is no voltage drop in the series resistance, hence voltage across load is more than full load condition. Ideally, if the voltage regulation is perfect, the voltage across the load should not depend on the load because of the negative feedback.

What is the magnitude of no load current as compared to full load current?

Explanation: The no load current is about 2-5% of the full load current and it accounts for the losses in a transformer.

Why motor takes more current?

Electrical overload or over-current is caused by an excessive current flow within the motor windings, exceeding the design current which the motor is able to carry efficiently and safely. This can be caused by a low supply voltage, resulting in the motor drawing in more current in an attempt to maintain its torque.

Why motor takes high current?

Probable causes of high current with load include mechanical overload, excessively high magnetic flux densities and, less frequently, an open rotor. An error in winding data that results in lower-than-design-level magnetic flux also can cause high current with load.

What is the difference between inrush current and starting current?

In rush is a short transient not dependant on the mass or load on a motor. The starting current is however dependant on what the motor has to drive and will be influenced by the torque needed to get the load spinning. “Starting Current” is that current which is required by any motor to first start it.