What are the differences between VFD motors and ordinary motors?

I have a good friend Linda especially do not like summer.

One reason is that Linda's sweat glands are special, hot days basically will not sweat, and therefore feel particularly uncomfortable; reason two is Linda's mosquito edge is particularly good, sometimes because of a mosquito cause a bad night's sleep.

Someone gave linda a "bad" idea: summer sleep with the air conditioner covered with quilts. Interestingly, this "bad" idea still works, Linda travel to use this method to avoid the heat, deal with mosquitoes; today we talk about VFD motor from the inverter air conditioner.

1. Variable frequency and fixed frequency air conditioners

Inverter air conditioners can control and adjust the speed of the compressor through the inverter, so that it is always in the best speed state.

That is, the compressor can be moderate temperature regulation in the case of long-term open operation: such as when the room does not need a lot of cooling or heating, the air conditioner will run in a low-frequency state, intelligent constant temperature control.

Fixed-frequency air conditioning to constantly start off the compressor, thus achieving constant temperature control, temperature fluctuations.

2 Frequency conversion motor characteristics

The above electric motor for inverter air conditioner is a typical application of inverter speed control motor.

General purpose inverter speed control motors have the following characteristics compared to ordinary motors: inverter motors

● Adopt inverter power supply.

●Change the conventional motor fan to an independent fan.

●The insulation requirement of motor winding is higher than that of ordinary motor.

● Because of the special characteristics of the frequency use of the motor, the frequency control motor is prone to resonance due to the electric motor during startup.

Full consideration should be given to the rigidity of the motor components and the whole to prevent vibration and noise problems of the motor.

● Insulation grade is generally chosen to be F or higher to strengthen the strength of ground insulation and inter-turn insulation to improve the electric motor insulation resistance to shock voltage.

● Special electromagnetic wire for inverter motors is used.

Especially for high-power motors, the requirements in this area are more strict because of the different application places.

●Forced ventilation cooling requirement.

Compared with ordinary motors, the motor speed is not unique, and if the motor is cooled by its own fan, the effect of ventilation and heat dissipation will be greatly reduced;

for this reason, an independent ventilation and heat dissipation scheme should be adopted.

In general, the use of axial flow to fan strong near ventilation; to pay special attention to the fan can not be a common power supply with the motor, the fan should be started before the motor starts, while in the shutdown should first shut down the motor power.

●Shaft current problem.

Bearing insulation measures should be adopted for motors with capacity over 160KW. Insulated bearings, insulated bearing chambers, increased current drainage carbon brushes and other measures can be adopted.

●Grease.

For constant power inverter motor, when the speed reaches 2P motor speed, special grease with high temperature resistance should be used to prevent the loss of bearing grease due to temperature rise, which will then cause bearing damage and winding burning.

● Manufacturing process control.

The vacuum pressure dipping paint manufacturing process and special insulation structure are used to ensure the insulation voltage and mechanical strength of the electrical winding.

● Rotor dynamic balance control to improve the precision of parts processing, and selection of bearings with high performance requirements, which can operate at high speed.

3 Inverter motor test

Generally need to use inverter power supply.

Because the inverter output frequency has a wide range of variation, and the output PWM wave contains rich harmonics.

The traditional transformer and power meter can no longer meet the measurement needs of the test, and the general Hall voltage, current sensor does not directly affect the power accuracy measurement of the angular difference index control and nominal.

It should use a clear ratio difference and angular difference index of the inverter power analyzer and inverter power sensor, etc. As the main power measurement instrument.

Find a professional electric motor manufacturer for VFD motor and normal IEC motor , please check from Dongchun motor China.

Dongchun motor is a professional manufacturer of electric motors in China.