Search FAQs

If I power a motor with an over-sized drive, will it dissipate less heat?

Issue:
Does a higher horsepower drive dissipate less heat when powering a lower than Drive rated horsepower motor?

Product Line:
Altivar Machines

Environment:
All models and serial numbers

Cause:
Customer needs a method to cool the drive more efficiently to prevent overheating faults.

Resolution:
No. Powering the motor with a higher horsepower rated drive in a sealed enclosure will not produce less heat, the "dissipated power" as stated in the catalog or installation manual remains the same.

Each drive requires a certain amount of power to operate. Larger drives require more power. The load on the motor will dictate how much power is required to operate the motor. With nothing changing other than the size of the drive, the motor will still require the same power to operate. However, the larger drive will require more power to operate its internal circuitry. The net power used will be more due to the larger drive requiring more power to operate. The end result will me more heat generated, not less,

To reduce the heat in a sealed enclosure it will be necessary to provide additional active or passive external cooling to the enclosure. Decreasing the switching frequency of the drive can also help. Note that when the switching frequency of the drive is lowered, the sound the drive makes while running will change. This can sometimes be loud. It will not interfere with the operation of the drive but in quieter environments it can become annoying.