Electrical help 3phs

Al Baker(pumpman) · Sep 30, 2021

I have 220v 3 phase in my shop. I bought a 5 hp 3 phase pedestal grinder years ago at auction. I would love to hook this monster up, but the tag doesn't give a step down chart and reads 440volts. Is there a transformer that will step up voltage for this grinder? I see step down ones listed for sale. IS this even possible. Thanks ,, Al

wore out · Sep 30, 2021

(quoted from post at 06:12:40 09/30/21) I have 220v 3 phase in my shop. I bought a 5 hp 3 phase pedestal grinder years ago at auction. I would love to hook this monster up, but the tag doesn't give a step down chart and reads 440volts. Is there a transformer that will step up voltage for this grinder? I see step down ones listed for sale. IS this even possible. Thanks ,, Al

Connect the "step down" transformer the opposite way, feed it 220 Volts and you will get 440 from the "input"/now" output".

Steve@Advance · Sep 30, 2021

Yes, you can back feed a 240/480 3 phase transformer and get your 480v.

But unless you can find a deal on a used one, it would not be financially practical.

Have you looked inside the motor enclosure? How many wires? If there is only 3, then the motor could be opened up and reconfigured for 240v. A motor shop could do that for you.

If there are multiple leads it can be changed over right there in the box. Typically there will be 9 leads.
Motor Leads

gene bender · Sep 30, 2021

Just take it to an electric shop and they will have the wires all connected into the three you need to hook up to your place

Billy Shafer · Sep 30, 2021

I think you should have someone look at you system. 440 is now 480. Most of the time no problem. But there are some of the old units where 440 means 440.Yes you can get stepup units.

John T · Sep 30, 2021

A transformer that can STEP UP and double voltage can also STEP DOWN and cut voltage in half. There's a chance the motor may have already windings so it can be used on 240 or 480, check that out. If you need to reverse direction, just swap any two leads. Overload protection as well as a disconnect method is required (typically in sight and within 50 feet) and a Combination Starter can provide both. I suggest consulting with a Motor Shop or an Electrician.

John T Century Electric Motor Company was my very first EE job out of school but Ive long since forgot most all of that grrrrrrrrrr

Mike Groom · Sep 30, 2021

In many cases if you take the cover off where the lead connections are it will list how to connect the leads to make it 440 or 220 volts on the motor.

Electrical help 3phs

Al Baker(pumpman)

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wore out

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Steve@Advance

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gene bender

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Billy Shafer

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John T

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Mike Groom

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