Source：Shengda Yu Published：2020-11-07 Clicks：10724
The main results are as follows: 1. Strengthen the mechanical strength at the whole connection of the squirrel cage bar and the end ring to avoid tilting and sweeping the chamber after the rotor squirrel cage bar is broken. The mechanical strength of the rotor end squirrel cage strip and end ring can be increased by making appropriate size steel ring or weft-free epoxy glass ribbon and steel wire binding. For the rotor with a small diameter, it can not tie steel wire or weft-free glass ribbon, but use a steel ring, wrapped with insulation, placed at the end, fastened with glass ribbon, and then dipped in paint to dry.
2. For the rotor where the mouse cage bar is loose in the iron core slot, the copper bar which is slightly larger than the original copper bar must be made into the slot hole, and the slot and copper bar clamp is not loose or warped.
3. Avoid motor overload, open frequently and for a short time, improve the operating condition of the motor, formulate a suitable operation mode, and ensure the safe operation of the motor. Technical modification of bar breaking of squirrel cage rotor of high voltage motor for maintenance.
1 replace the broken rotor copper bar. If the copper bar is broken or the crack is in the groove, the welding part in the corresponding hole in the end ring is first milled with a milling machine, the broken guide bar is ejected with a steel rod matched with the groove, and the core groove is carefully cleaned to check that there are no sundries in the groove. Then insert the recustomized copper bar into the rotor slot.
(2) the cage bar is welded with the end ring, the welding position is thoroughly cleaned before brazing, and the 45 °slope is coated with solvent for welding. In order to reduce the internal stress and ensure the strength, braze at low temperature and heat evenly. When the temperature reaches 800 ℃, use 45% silver solder rod to reduce contact resistance; touch the joint, let the solder dissolve and gradually fill the gap. After welding 5 joints, turn 180 °and then weld the other side of the joint, cross welding, in order to reduce the residual stress after welding. After brazing, when the end ring is cooled to 180 ℃, rinse with 10% citric acid aqueous solution and blow dry.
(3) the protective ring adopts magnetic steel ring, the process should be standard, and the hot sleeve method should be used. The thickness is 2mm, and the thickness shall not exceed the outer circle of the core.
(4) weft-free glass ribbon binding. Tie with a thickness of 0.17 mm and a width of 25 mm or 15 mm with weft-free epoxy glass ribbon. The rotor is placed on the binding machine, the weft-free glass ribbon is pulled to the rotor by the tension device, the appropriate pulling force and speed are adjusted, and then winding and binding is carried out, and the binding thickness shall not exceed the outer circle of the rotor core. After theweft-free glass ribbon is impregnated and dried and cured, it can be struck with a smallhammer to produce a crisp metal sound as qualified. File the hoop ring with a file.