How to judge and repair the broken rod of the squirrel cage?
When the diameter of the rotor of the motor is below 6000mm, the cast aluminum rotor is mostly used, while the medium-sized motor is made of copper rod rotor. Broken rods and broken rings of squirrel cages are collectively referred to as broken cages or broken bars. A broken strip means that one or several pieces of the squirrel cage are broken or have serious air bubbles, and the broken ring means that there is one or several cracks in the end ring.
Usually, the squirrel cage rotor is relatively strong and not easily damaged. However, when the cast aluminum or cast copper squirrel cage rotor is rough in manufacturing process, poor in quality or unreasonable in design, frequent start-up and improper operation, the rapid and violent reversal will cause severe impact, resulting in broken rods in the cage.
If the squirrel cage motor only breaks one or two bars, it has no obvious influence on the motor operation, and the broken bar will affect the normal operation of the motor.
When the motor squirrel cage rotor is broken, the following phenomenon will occur.
1 The motor starting torque is significantly reduced. If the rotor is swung left and right when starting again after stopping, the motor will not start running.
2 When the load is running, the ammeter pointer makes a periodic swing.
3 When the load is full, the speed is obviously reduced, the rotor is overheated, the fuselage is violently shaken, the temperature is increased, and there is a large noise.
4 When the motor starts, it will splash Mars from the air passage.
