Haier Washing Machine Maintenance Case: Leaking Electricity in Letida XQG50-WN55X Washing Machine
Fault Phenomenon: The motor casing is electrified, causing electric shock to people.
Detection and Judgment: This situation is caused by the motor winding grounding. The reasons for this fault are as follows:
(1) The wires of the motor winding loosen and touch or scrape the metal parts;
(2) Severe moisture in the motor causes aging of the insulation layer;
(3) Poor quality of the motor itself.
Using a 500V megohmmeter to measure the insulation resistance of the winding to ground, it was found that the reading fluctuates, indicating that the insulation of the motor has been basically destroyed. A small light bulb powered by a low-voltage power supply can be used to find the grounding point. Two batteries (1.5V each) and a small light bulb can be connected in series, with one end on the motor casing and the other end connected to the lead wire of the main winding or auxiliary winding (note to disconnect the main and auxiliary windings). If the bulb lights up, it indicates that the winding has grounded. At this point, tapping the end of the winding indirectly with a wooden hammer, if the bulb also flickers, it indicates that this is the grounding point. After checking with the above method, it was found that the grounding point of the motor is on the outside of the winding.
Repair Method: Use insulating paper to separate the wires from the core, locally immerse in insulating varnish, and after the varnish dries, install and use it. The fault is eliminated.
Repair Experience: If the internal damage of the motor winding causes grounding, then according to the detected position, immerse it in insulating varnish, let the varnish dry, and then immerse it again. Then use a 500V megohmmeter to measure its insulation resistance. If the measured insulation is above 50MΩ, it indicates that the grounding fault has been eliminated.
Source of Article: http://blog.sina.com.cn/haierxyj114