Can a 37KW pump be used with a 30KW frequency converter?
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This post was last edited by 955559 on 2019-2-26 at 15:37. The process requires 80 m3/h and a head of 20 meters. The customer has a pump they would like to use. But it is 160 m3/h, with a head of about 40 meters and a power output of 37 KW. Since the design capacity will not exceed 100 m3/h, can a 30 KW frequency converter be used to reduce the speed in order to achieve a flow rate of 100 m3/h along with a lower head pressure? A forum member replied that they were not aware of the specific conditions on site, and advised against using a 30KW inverter. 1. If the frequency converter is added only for process requirements, it is not necessary. 2. To make use of existing equipment, the shaft power can be reduced by cutting the impeller; however, the power level after cutting might still be higher than what is required by the process. It’s not clear whether the process requirements are very strict. 3. Choose a frequency converter with a capacity of 37 KW that matches the motor, and then reduce the frequency. The question now is: with a voltage of 440V and 60Hz, can an inverter enable the pump to operate at below 30Hz for an extended period of time? Is it more energy-efficient to use variable-frequency low-speed operation in this case, or is it better to choose a new pump as designed (a 7.5KW pump plus a 7.5KW frequency converter) for better energy savings?
A forum member replied that they were not aware of the specific conditions on site, and advised against using a 30KW inverter. 1. If the frequency converter is added only for process requirements, it is not necessary. 2. To make use of existing equipment, the shaft power can be reduced by cutting the impeller; however, the power level after cutting might still be higher than what is required by the process. It’s not clear whether the process requirements are very strict. 3. Choose a frequency converter of 37 KW that matches the motor, and then reduce the frequency
Those in electrical engineering probably can’t do the calculations, but those in process engineering should be able to
The question now is: with a voltage of 440V and 60Hz, can an inverter enable the pump to operate at below 30Hz for an extended period of time? Is it more energy-efficient to use variable-frequency low-speed operation in this case, or is it better to choose a new pump as designed (a 7.5KW pump plus a 7.5KW frequency converter) for better energy savings?
Inverters definitely have this capability; that’s exactly what they are designed for. However, for a 37KW motor, it’s best to use a 37KW frequency converter; the price of a 30KW frequency converter is roughly the same as that of a 37KW one. Also, the motor fitted to this pump should be a power-frequency motor.
Right. It is a power-frequency motor. Thank you