Frequency explosion-proof motor with frequency converter to adjust speed, frequency converter for frequency conversion play a protective role, explosion-proof electric motor, such as overload, short of equal reason can avoid relatively, but not with the inverter will not burning motor, if the over-current protection set is too large, brushless motor running at 100% above the current for long time, would be easy to burning motor, and frequent start-stop, current is too high, also easy burning motor. So, not with the inverter can rest easy, also need to set parameters correctly, can not blindly increasing overload coefficient, seeing much of motor, and pay attention to the load change.
mixer inverter frequency conversion motor burning is generally turn-to-turn short circuit and open circuit, the phenomenon such as short circuit, under the power frequency power supply, receiving voltage explosion-proof motor winding is three-phase sine wave voltage of 50 hz, winding induction voltage is lower, smaller surge component in a circuit. And under the inverter power supply, inverter inverter converts dc, three-phase ac voltage by controlling the switch element conduction, six bridge arm is broken, to realize the three-phase ac output voltage, the frequency is about thousands of ten thousands Hertz. Then receive the explosion-proof motor winding voltage impact is bigger, the voltage change rate increase, make the motor winding interturn voltage change rate is very high, winding voltage distribution becomes very uneven, make the turn-to-turn insulation test under great, such as motor winding short circuit, motor increasing failure rate.
the inverter output voltage waveform, under the high-speed switching effect of semiconductor switch, voltage will allow superimposed on the motor running voltage, can produce pulse on the motor terminal over-voltage, peak is about 2 times of dc voltage, pose a threat to ground insulation of brushless motor, the ground under the repeated impact of high voltage insulation can accelerate ageing.
there is also a kind of situation, make ordinary explosion-proof motor frequency conversion explosion-proof motor, due to the ordinary motor fan is with motor shaft is, when the motor running in low frequency for a long time, motor speed is low, together with the motor shaft of the fan will speed is too low, cause lack of motor cooling, serious when even burning motor.
inverter cause burning motor mainly have three:
spending the first is make ordinary motor frequency conversion motor
spending the second kind is connected directly to frequency conversion motor without debugging parameters
spending is the third kind of frequency conversion fan operation direction inconsistent with fan identification, lead to fan can not play a role of normal, cause lack of explosion-proof motor cooling, heat accumulation, serious when burning motor
do according to the above situation, we when choosing frequency converter and inverter explosion-proof motor, to choose a big manufacturer of good quality, although the comparison when looking at your point, but of good quality and long run is not easy to burning motor, it down or cheaper.
