Several Methods for Motor Maintenance in Tianjin?
In electrical motor maintenance, various situations can arise, such as selecting effective repair methods to prevent getting lost in the process and achieving twice the results with half the effort. We have compiled several motor repair methods based on our experience and insights from routine maintenance work, which are crucial for reducing motor insulation resistance. Issues such as ground connections within the stator winding slots, short circuits between winding turns, broken bars in squirrel-cage motor rotors, and "setting off fireworks" between motors, as well as the disassembly and reinstallation of old windings, and the handling and repair methods for damaged motor rotors, shafts, end covers, and roller bearings are provided for reference only.
After installing the end cover, the motor's insulation resistance has decreased.
Prior to installing the side covers during the repair of a cage motor, the insulation resistance is reduced after installation. This situation can distinguish issues on both sides of the winding. The cause of the reduced insulation resistance may be partial scratches on the enamel coating of the wire or deviations in the winding mold, leading to an excessively long extension at the top of the winding. Due to the proximity or contact of the inner wall of the end cover to the problem point, the winding's insulation resistance decreases.
To address this issue, the first step is to identify which end of the motor is problematic. The method of distinction is as follows: first, install one end cover, and use a 500V insulation resistance meter to measure the insulation resistance of the winding. If it's low, it indicates there is an issue with the winding. Next, remove the end cover and install the other end cover, then measure the insulation resistance of the winding again. If it's still low, it suggests that there is also an issue with the other end. Throughout the entire process of removing and installing end covers, the motor rotor should remain stationary.
After identifying the problematic area, typically a slight trimming is performed on the top of the winding, followed by the application of some three-in-one protective varnish. If it's not too difficult to handle, it's easy to pad a layer of plastic film over the contact area between the winding's top and the inside of the end cover. Generally, the issue can be resolved.
2. Stator winding slot connections within the stator winding slot
Grounding devices within the stator winding slots usually occur at the slot mouth. This is due to the slot insulation paper being damaged, either because it is improperly placed or because it has been dislodged. If the marking is not careful, placing the insulated wire below the slot insulation paper, or breaking the slot insulation paper when inserting the slot wedge, can lead to issues with the grounding device.
To address this issue, first determine if the motor winding is damp. If it is damp, the motor should be dried, as this would render the results ineffective.
