Basic knowledge of safe operation of electric motors and common troubleshooting methods

Release time

2022-08-11 11:38

The stator and rotor are the components required by the motor. The stator is fixedly installed on the casing, and a coil is generally wound on the upper surface of the stator; the rotor is installed and fixed on the machine table through bearings or bosses, and the rotor has silicon steel plates and coils. The coil generates a magnetic field on the silicon steel plate of the stator and rotor, and the rotor rotates through the magnetic field. Let's learn about the basic knowledge of safe operation of the motor and the solutions to common faults!

1. The stator of an asynchronous motor consists of a stator core, a stator winding and a machine.

1. Stator iron core

The role of the stator core is as a part of the magnetic circuit of the motor and embedded in the stator winding. The stator iron core is made of laminated silicon steel plates with a thickness of 0.5mm. Insulating paint is applied on both sides of the brick steel plate to insulate the plates from each other, thereby reducing the core loss caused by the rotating magnetic field on the stator iron core. Several identical slots for inserting stator windings are opened on the inner side of the stator core.

2. Stator winding

The stator winding is the circuit part of the motor, and its main function is to generate the induced potential through the current to realize the conversion of electromechanical energy. The distribution of the stator winding coils in the stator slots is divided into two types: single-layer and double-layer. In order to obtain good electromagnetic performance, double short-distance windings are used in medium and large asynchronous motors.

3. Stator machine

The main function of the machine is to fix and support the stator core, so it is required to have sufficient mechanical strength and rigidity to withstand various forces during motor operation or transportation. Medium and small AC motors - generally use cast iron machines, and large-capacity AC motors generally use steel plate welding machines.

2. The rotor of the asynchronous motor is composed of the rotor iron core, the rotor winding and the rotating shaft.

1. Rotor core

The rotating iron core is a part of the magnetic circuit of the motor, and together with the stator iron core and the air gap constitute the whole magnetic circuit of the motor. The rotor core is generally made of 0.5mm thick silicon steel plates stacked. Most of the rotor cores of medium and small AC motors are directly installed on the motor shaft. The rotor core of the large AC motor is mounted on the bracket, and the bracket is embedded in the shaft.

2. The function of the wound rotor winding is to generate electromagnetic torque by inducing potential and current, and its structure has two types: cage type and wound type.

1. Squirrel rotor

A cage winding is a winding that closes on its own. Guide rails are inserted into each slot, and two end rings are respectively connected to both ends of all guide rails in the incisions protruding toward both ends of the iron core. After removing the iron core, the shape of the entire winding looks like a "circular cage", so it is called a cage rotor.

2. Wound rotor

The wound rotor winding is similar to the fixed winding. It is embedded in the slot of the rotor core with insulated wires and connected to a star-shaped three-phase symmetrical winding. Then, connect the 3 small wire ends to the 3 collector rings that rotate around the axis respectively, and draw the current through the brush. The characteristic of the winding rotor is that an external resistor is added to the winding circuit through the collector ring and the brush, which can improve the starting performance of the motor and adjust the speed of the motor. In order to reduce the wear of the brush, the wound asynchronous motor is sometimes equipped with a brush short-circuit device, which is used to raise the brush when the motor does not need to adjust the speed, so that the three collector rings are short-circuited at the same time.

The above is the basic knowledge of safe operation of electric motors and common troubleshooting methods. If you want to know more, please feel free to contact us!

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