380V/50Hz motor running at 480V/50Hz

[rockodilered]

What would the effect be of running a 10hp 380V/50Hz motor at 480V/50Hz if the load would not change. Since the V/Hz ratio increases this would increase the back EMF which would draw more current, but the higher voltage would mean that the motor would not need to draw as much current to run the same load at the same frequency. Do these two effects cancel each other out allowing me to use the same motor? Or should I get a larger motor and derate it?

 

[davidbeach]

You'd saturate the iron of the motor on the greatly increased V/Hz and probably fry the motor.

 

[dpc]

Other than that, there should be no problems

 

[edison123]

dpc - lol.

Why you would another 380 V motor with a higher hp ? Buy a 480 V, same hp.

 

[waross]

Using a larger motor on over voltage would result in a larger motor burning up.
I would use a pair of dry type 120:480 transformers in open delta autotransformer boost configuration.
The individual transformers are wired as 480:600 volt autotransformers.
When 480 volts is fed to the 600 volt connection the output is 384 volts. The transformers are sized so that the 120volt winding is capable of supplying the motor full load current.
I have used this connection many times to convert both ways between 480V and 600V for 460V and 550V motors.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[EEBubba]

I would agree with Davidbeach, the magnetic fluxes would rise in the motor and you might be working the core steel into saturation.

Best advice, contact the manufacturer and they can tell you if it is acceptable and predict the performance to a fairly good accuracy. This should be a very quick review for them.