Maintenance method of variable frequency motor and general motor is basically the same, but due to the particularity of inverter motor winding than ordinary strict frequency motor insulation, should take the following measures to improve the insulation condition:

First, choose the corona resistant electromagnetic wire to meet the requirements of high frequency pulse and partial discharge of the motor. Generally use polyester imide / polyamide imide composite layer enameled wire, corona resistance, corona resistant electromagnetic wire.

Two 、 winding and embedding line construction technology.

Variable frequency motor must be strict management in winding and inlay and binding process, especially to prevent damage to the wire in the winding and inlay process, embedding process should ensure slot insulation, insulation, insulation in place. Phase insulation shall be made of materials which are easily soaked by insulating paint, and the ends of the coils shall be reinforced and secured so as to ensure that the ends become a whole.

Insulation is strengthened at the bottom, interphase, interlayer and coil head, end, turn of the motor, which can improve the electric strength of the motor.

Three. The main insulation shall be insulated without air gap.

The air gap in the insulation structure of frequency conversion motor is the main factor of corona generation. In order to ensure the whole motor insulation structure without air gap, according to the national standard GB/TZ1707 2008 "special frequency control three-phase asynchronous motor insulation standards", impregnating the VVVF three-phase asynchronous motor for special must be not less than F solventless paint, and volatile parts of less than 10%, and the use of VPI technology. The process also improves the overall mechanical strength of the insulation structure.

Four, do a good job of frequency converter, cable and motor matching, limiting the length of the cable between the motor and the power supply.

Due to the mismatch of the impedance of the power line, as the cable length increases between the converter and the motor, the amplitude of the overvoltage at the motor end increases, which makes it easy to cause partial discharge. Therefore, the length of the coupling cable should be shortened as much as possible according to the specific characteristics of the inverter and the actual needs, so as to reduce the over-voltage amplitude and partial discharge of the motor and prolong the service life of the motor.

Frequency conversion motor power line generally use professional electricity, also known as symmetrical conductor frequency conversion cable, is 3P+3N/E series, that is, the original 3+1 in 1, divided into 3.