38 Roll Threader hook up

[deetz]

We just bought 38 Roll Threaders that are basically 42 FLA each. They came from overseas and have a 380v/220v label. We have 480v at our facility. What would be the best and most economical solution to power these all up? I am trying to find out if the motors are rated for 480v and just had the labels changed. The motor labels are in English. Otherwise I could get a transformer big enough to power a buss bar and connect off of that. How big of a transformer would I need though is another question. I could just get a transformer for each also, which if they decide to move any of them to one of our other facilities, would just go with it then.

 

[waross]

Check out this FAQ Motors: Changing between a 50 and 60Hz supply. faq237-1224
Quickly: The Volts per Hertz ratio should be maintained.
380 Volts / 50 Hertz = 7.6 V/Hz
7.6 V/Hz x 60 Hz = 456 V0lts Close enough to 460 Volts.
Standard motors for use on nominal 480 Volt systems are rated for 460 Volts.
The torque will be the same.
The rated and safe full load current will be the same.
The speed will increase in the ratio of 6/5 or 20%.
The useability depends on the speed/torque characteristics of the load. If there is enough torque available to drive the load 20% faster you are good to go.
If the torque demands at 120% of rated speed exceeds the capacity of your motors you have a problem.
If you have a belt or chain drive you may change the drive ratio.
It may be well to ask jraef about the feasibility of running 38 motors on one or more VFDs.
Comments Jeff?

Bill
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