Maintenance of motor faults in commonly used compressors

1. Winding wire breakage inspection

Spread out the power cord inside the motor junction box and connect it in series with a megohmmeter, multimeter, or calibration lamp between the terminal and neutral of the running winding (or starting winding) for inspection. If the meter is not connected, the resistance is high, or the light is not on, it indicates that there is a broken circuit in the winding.

2. Winding short circuit inspection

A megohmmeter or multimeter can be used to check the insulation between any two phase windings. If the insulation resistance is very low, it indicates a short circuit between the windings. Motor winding short circuits include phase to phase short circuits, short circuits between windings, short circuits between turns of windings, etc.

3. Winding leakage inspection

The motor winding may be damaged due to moisture, insulation aging, transportation, and other factors that may cause the insulation of the enameled wire to collide with the motor winding and the casing. Due to the use of the motor in harsh environments (such as high ambient temperatures and poor heat dissipation), the overload protection of the relay fails, causing the motor winding to overheat and damage the insulation. All of the above factors may cause leakage faults.

The insulation performance of the motor decreases due to moisture, and it should be dried. If it is a sealed motor, the whole machine can be placed in a box and baked at 110 ℃ for 6 to 8 hours. For motor windings with insulation damage or leakage faults, they can only be rewired.

4. Method of rewinding the motor winding

(1) After determining the motor fault, all windings should be removed, and the wire diameter and original number of turns of the wire should be recorded before removal.

(2) Remove the winding and scrape off the original insulation layer in the stator slot, then re insert the insulation material. Generally, 120 grams of kraft paper and plastic film are used for stator insulation.

(3) Rewind the winding according to the original number of turns and measure its resistance.

(4) Insert each winding into the original slot in the direction of the original winding to prevent wire crossing.

(5) Tie the winding tightly with cotton rope, install it into the rotor, conduct a power test, and after starting normally, put the motor into a drying oven with a temperature of 100 ℃ for drying. It can be used after 4 to 6 hours.