Common faults and treatment methods of motors
Short circuit between iron chips
1: The iron core lamination is slack. When the generator is running, the iron core vibrates and damages the insulation; if the insulation of the iron chip is damaged or the core is partially overheated, the insulation is aged, and the method is processed according to the original plan.
2: There is a burr on the edge of the iron chip or mechanical damage during maintenance. Use a fine boring tool to remove the burrs, trim the damage, clean the surface, and then apply a layer of silicon steel paint.
3: If there is solder or copper short-circuited iron core, the metal welding joint should be scraped or cut off to deal with the surface.
4: The arc is short-circuited by the winding, which may also cause the core to be short-circuited. The burned part should be removed with a chisel and the surface should be treated.
The generator loses residual magnetism and cannot generate electricity when starting
1: The residual magnetism is often lost after the shutdown, because the material used for the magnetic pole of the exciter is close to the soft steel, and the residual magnetism is less. When the field winding has no current after the shutdown, the magnetic field disappears. A battery should be provided to magnetize before power generation.
2: The magnetic pole of the generator loses its magnetic force. It should be magnetized in the winding with a DC current (short time) larger than the rated current to recover enough residual magnetism.
Excitation reactor temperature of automatic excitation device is too high
1: The reactor coil is partially short-circuited and the reactor should be repaired.
2: The air gap of the magnetic circuit of the reactor is too large, and the air gap should be adjusted.
After the generator starts, the voltage does not rise.
1: The excitation circuit is disconnected, so that the voltage does not rise. Check the excitation circuit for broken wires and good contact.
2: The residual magnet disappears. If the exciter voltmeter has no instructions to indicate that the residual magnet has disappeared, the exciter should be magnetized.
3: The polarity of the field coil of the exciter is reversed, and its positive and negative connecting lines should be reversed.
4: When performing some tests in the generator overhaul, the magnetic field coil is mistakenly connected to the reverse direct current, causing the residual magnet to disappear or reverse, and the magnetization should be re-energized.