What Is The Principle of Induction Motor? What Is Its Advantage

Induction motors are widely used in home appliances and industrial fields, such as washing machine motors, small water pumps, and ceiling fans. There are two types of rotary induction motors: squirrel-cage induction motors and wound rotor induction motors. Wound induction motors are also known as slip ring induction motors (Slip Ring Induction Motor). Squirrel cage induction motors are widely used in industry, especially where speed regulation is not required, such as: submersible pumps, lathes, mills, conveyor belts, flour mills, compressors and other low mechanical power applications. Slip ring induction motors are used in heavy duty applications where high initial torque is required, such as: steel mills, cranes and hoists, drive shafts and other heavy machinery workshops, etc. So how does an induction motor move? What are its advantages and disadvantages? I will share it today.

Here is the list

Faraday's law of induction motor

The relationship between the law of electromagnetic induction and the induction motor

What is the working process of the induction motor

Faraday's law of electromagnetic induction

First, what is induction? In fact, the induction here is not whether you can sense her (him), but Faraday's electromagnetic induction, haha. Faraday's law of electromagnetic induction states that any change in the magnetic environment of a wire coil induces an electromotive force in the coil. Regardless of how the magnetic change is created, whether by moving the magnets and coils relative to each other or by changing the magnetic field, a voltage is created.

The magnet and the coil move relative to each other, and the magnetic field environment where the right coil is located changes, and a voltage is induced in it. The magnet and the coil are relatively stationary, but the magnetic field generated by the coil on the left, because the alternating current itself is changing, a changing magnetic field is generated in the coil on the left, so a voltage is also induced in the coil on the right, which is connected to the light bulb of the circuit light up.

When the bar magnet is inserted into the coil, the magnetic field in the coil is strengthened, and the current induced in the coil creates another magnetic field, which is opposite to the original magnetic field to prevent the magnetic field from increasing (there will be a reaction force that prevents the magnet from moving). Come to think of it, this is also the basic law of electromagnetic induction, and it has to stop you from changing. If it's to drive your change, think about the consequences. Maybe you accidentally invented a perpetual motion machine, then your life is free.

The relationship between the law of electromagnetic induction and the induction motor

The magnet and the coil are relatively static, but the magnetic field generated by the left coil, because the alternating current itself is changing, produces a changing magnetic field in the left coil, so the right coil also induces a voltage, which is measured by the following voltmeter. Think about it, in fact, the transformer is the same principle, but the coil of this transformer is empty, can not guide the magnetic field well, can not make full use of the magnetic field, the efficiency is not high, but the underlying logic is the same.

What is the working process of the induction motor

When the upper coil is energized, a magnetic field is generated. When the switch is opened and closed, the magnetic field changes suddenly, which in turn induces an electromotive force in the lower coil. When the circuit is closed, a current is generated, and the current is recorded by the ammeter. If the switch remains closed or open at all times, no current flow is detected because there is no magnetic field change and no induced voltage is generated.

In fact, in a permanent magnet motor, when the coil moves rapidly, the magnetic field in which it is placed also changes, creating an induced electromotive force. This electromotive force is opposite to the input voltage, so it is called back electromotive force. The back EMF is related to the speed, current and speed of the motor. Proportional to the strength of the magnetic field, it reduces the voltage across the coil, which reduces the current and limits acceleration.

Hangzhou New Hengli Electric Machine MFG. Co., Ltd. (Originally Hangzhou Hengli Electric Machine MFG. Co., Ltd.) was founded in 1954.