Use of 60 Hz m/cs on 50 Hz system

As long as the V/f is maintained constant, the motor stator laminations / core is safe.

Speed ofcourse is going to be lower as it is proportional to frequency.

Torque is proportional to square of V and hence will be lower.

Motor cooling will be lower as the shaft mounted fan is going o run at lesser speed. Hence, temperature rise of the motor will be higher and may call for derating.

That's all I can think of with my limited knowldge of motors.

This is one of the common questions asked in CR4. There is a very good general discussion on this topic in thread http://cr4.globalspec.com/thread/33399. Hope you will find the required information.

Here is the summary of this discussion:

In order to keep the flux within limits, a linear V/F ratio must be maintained. If the frequency is reduced by 10%, the voltage must also be reduced by 10%. Since the flux remains the same, the torque capacity remains same and thus the power rating of the motor also drops by same %. Provided the voltage is dropped by the same proportion as the frequency, it is OK to run a 60Hz motor on 50Hz. The speed will be reduced by the reduction in frequency and the power capacity will also reduce by the reduction in frequency.

Maintaining V/f (voltage / frequency) will maintain same magnetic flux. However due to 17% reduction in frequency (50/60)

- The motor turns 17% slower.

- The internal current goes up by 17% to maintain the same flux.

- The power (watt) goes down by 17 %

- The mechanical cooling is less, because of 17% less rotation of fan.

- The result is a higher current, than designed and the insulation of the electrical wiring deteriorate much quicker, unable to dissipate the heat, which after sometime results in a burn-out.

- MS

Most of the problems are burnt windings, due to less everything, just about 17-20 % of what you can expect from a 60 Hz net. Heat dissipation will keep you busy replacing these. A frequency converter 50 to 60 may help.

Thank you all for your responses.........the answer to my fundamental question, however, is still elusive....and that is:- is there a techno-commecrially sensible solution that will allow me to have the same Head/Flow/Throughput of the driven machines if I were to use the 60 Hz drive motors on 50 Hz system. Any specific charecteristic VVVF drive or FCMA (Flux conterolled mag amp) etc? Shall look forward to some help on these lines.

Tilak Ghoshal

No, there isn't.