The frequency of the variable-frequency motor is low
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This post was last edited by zhaohh3211 on 2010-7-19 09:29. Our factory has a variable-frequency pump, and I would like to ask everyone: what are the negative effects on the inverter if the frequency variation is too low (in terms of percentage, like 2%)? Is it acceptable to operate the pump in such conditions under normal circumstances?
It is not allowed. In the chemical industry, if the frequency of the motor is below 10 Hz, that is, 20%, the pump driven by the motor will not produce any flow at all. When the frequency is below 5 Hz, the motor basically stops working, and it also heats up when its speed is low.
This post was last edited by zhaohh3211 on 2010-7-19 09:26. Such a situation is not acceptable; a frequency conversion level of 2% is too low for pump motors. Moreover, there is little need for such a setting. For pump motors, if the frequency conversion level is too low, insufficient power can be output, and in that case all of that power is wasted as heat generated by the motor. If this condition persists for too long, it will cause the motor to generate excessive heat, thereby damaging it!
This post was last edited by zhaohh3211 on 2010-7-19 09:27. Reply 1# *aodouzi: If the parameters are not set correctly, it may damage the motor. Well, if start-up, overheat, and overload protection are set up, I don’t think there’s anything wrong with that; it’s just a waste of resources. When taking the technician exam, there was a question about the parameter setting of frequency converters, but the instructor didn’t mention this topic either; during the training...
Generally speaking, it has no negative effects on the inverter itself; on the contrary, it only has advantages. However, it affects the motor, results in insufficient utilization, and also increases the motor’s heat generation. But this also often happens during production; for example, in the reactors used in installations, when the reactors are in operation (such as during startup or shutdown), the speed of the motor is very low, around 20% of its normal speed, and there are no issues with operation at this time.