Motor maintenance, high voltage motor winding earth fault analysis and processing, with high efficiency, energy saving, low noise, little vibration, light weight, reliable performance, easy installation and maintenance, etc. Since put into operation has been operating normally, but in the last December, in the operation of the motor in protection action, monitoring shows that the motor stator winding grounding signal, a preliminary shaking table measuring cables and electrical insulation, found grounding phenomenon, after we receive the notice, the motor terminal box to solve cable joint, respectively, measure of cable and motor using 2500 v megohmmeter, measured motor insulation to ground is 0.5 M Ω, cable is 3500 M Ω, it can determine for motor stator winding grounding.

A, we know that the motor winding earth fault outside notting have the following several ways:

1, motor overload for a long time, cause breakdown insulation of insulation aging metamorphism;

2, electrical, lightning overvoltage or operating over-voltage breakdown of insulation;

3 when suddenly disconnected, synchronous motor excitation coil, coil to ground insulation; high voltage breakdown,

Creepage distance was reduced by 4, due to the conductive dust, produce breakdown or flashover to ground;

5, ventilating ducts gaskets, finger tooth clamp open welding or rivet is flabby, core laminate is not tight, of fibrillation and crooked teeth clamp blow grind coil insulation, resulting in failure of winding grounding;

6, asynchronous motor excitation coil insulation aging contraction, fibrillation, often under the motor rev, braking frequently make insulation damage on breakdown;

7, caused by coil short-circuit burning insulation, to ground