Principle of Operation of Asynchronous Electric Motors
Asynchronous electric motors (AC), which are widely used in industry, operate based on the conversion of electrical energy into radial mechanical rotation. These mechanisms got their name due to the slight difference (desynchronization) between the rotational speeds of the stationary magnetic field and the rotor.
Types of Asynchronous Motors
Single-phase asynchronous motors are designed to operate in 220 Volt electrical networks and are used in various models of household appliances. In contrast, three-phase motors are usually employed as drives for actuating mechanisms in large industrial installations.
Faults and Their Elimination
The need for repair of asynchronous motors generally arises after the detection of such characteristic faults:
- short circuit between windings;
- destruction or severe overheating of rotor bearings;
- damage to the stator insulation;
- loosening or complete breakage of connections for terminal connectors.
To address the above-mentioned faults, it is best to consult specialists who specialize in the repair of motors of this class.
Repairing Bearings of Asynchronous Motors
An example of self-repair of asynchronous machines is the replacement of bearings.
Bearings belong to the class of support units that ensure the normal operation of rotating moving parts of the AC (rotor or armature), withstanding both radial and axial loads.
Typical Bearing Faults
Among the most characteristic faults of rolling elements (bearings) can be highlighted:
- overheating of the bearing housing due to contamination or lack of lubrication;
- strong noises in the housing of the rolling element, which occur during acceleration and deceleration of the rotor;
- leakage of lubrication from the bearing retainer.
Process of Replacing Bearings
- First, one of the motor housing covers (front or rear) is removed.
- Then, using a special puller, the rotor of the motor is detached.
- After this, the bearings are removed from their mounting seats and replaced with new ones.
- The assembly of the motor is carried out in the reverse order of disassembly.
After the assembly is completed, the electric motor is started with the load connected and checked for the absence of foreign noises.