The difference between frequency conversion motor and ordinary motor maintenance method

2021-11-04 09:23:27 jact_elec

The difference between frequency conversion motor and ordinary motor maintenance method

The frequency conversion motor and the frequency inverter are two independent electrical components, so the frequency conversion motor itself does not contain the frequency converter. The frequency conversion motor needs to select the appropriate frequency converter according to the motor parameters to realize the adjustment of the motor speed.

Variable frequency motor refers to a motor that runs continuously within the range of 10% to 100% rated speed at 100% rated load under standard environmental conditions, and the temperature rise will not exceed the motor's calibrated allowable value. Is there any difference between the maintenance method of the frequency conversion motor and the ordinary motor? Due to the particularity of the variable frequency power supply, the winding insulation of the variable frequency motor is stricter than that of the ordinary motor. Jact will introduce the details through the next article:

1. Choose electromagnetic wire with good corona resistance to meet the requirements of motor resistance to high frequency pulse and partial discharge. Generally use polyesterimide/polyamideimide composite layer enameled wire, corona-resistant and anti-corona electromagnetic wire.

2. Construction technology of winding and embedding. Inverter motors must be strictly managed in the winding, embedding, and binding processes, especially in the process of winding and embedding to prevent damage to the wires. The embedding process should ensure that the slot insulation, phase insulation, and interlayer insulation are placed in place. The phase insulation should be made of materials that are easily penetrated by the insulating paint, and the coil ends should be bound and fixed to ensure that the ends become a whole. Reinforce the insulation at the bottom of the motor slot, between phases, between layers and the first and last turns of the coil, which can improve the electrical strength of the motor.

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3. The main insulation must be non-air gap insulation. The air gap in the insulation structure of the frequency conversion motor is the main cause of corona. In order to ensure that there is no air gap in the overall insulation structure of the motor, according to the national standard GB/TZ1707-2008 "Specification for Insulation of Three-phase Asynchronous Motors for Variable Frequency Speed Regulation", the impregnating varnish for three-phase asynchronous motors for variable frequency speed regulation must be no It is lower than F grade solvent-free paint, and has a volatile content of less than 10%, and adopts VPI process. The process also improves the overall mechanical strength of the insulating structure.

Fourth, do a good job in matching the inverter, cable and motor, and limit the length of the cable between the motor and the power supply. Due to the mismatch of the power line impedance, as the length of the cable between the inverter and the motor increases, the amplitude of the overvoltage at the motor end increases, which is likely to cause partial discharge. For this reason, the length of the connecting cable should be shortened as much as possible according to the characteristics of the specific variable frequency power supply and actual needs, so as to reduce the overvoltage amplitude and partial discharge at the motor end and extend the life of the motor. The frequency conversion motor power cord generally uses professional cables, also called symmetrical conductor frequency conversion cables, which are 3P+3N/E series, that is, 1 of the original 3+1 is divided into three.

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