3-wire 440V motor to 220V possible?

8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• Apr 21, 2018

• #1

I just picked up a 15hp TEFC motor from Brook Ltd back in the 1950s in england.

The guy that sold it to me told me it was a 9 wire motor, turns out he lied, it is 3 wire.
The swap was in a parking lot and it was rainy. I didn't look and took his word for it,
and now i have it in the shop, it's got a data plate that had 220V on it, and it's striked out
and 440 is below it. Am i screwed? I thought i would pull the end bell off it, and see if i could
identify the connections to pull them out and reconnect for 220V.

I've got a sneaky suspicion i just bought a 150 dollar paperweight. I haven't gotten far into taking the
end off yet.

Any ideas?

 

L

Larry Dickman

Titanium

Joined

Jan 30, 2014

Location

Temecula, Ca

• Apr 21, 2018

• #2

I had a motor a while back that was wound for 440 only. I took it to a motor shop and they converted it to 220v, for about $150.

 

J

johansen

Stainless

Joined

Aug 16, 2014

Location

silverdale wa

• Apr 21, 2018

• #3

if it was rewound and 3 wire only, at a minimum you can connect it in delta for 277 and run it from 240vac, you can load it to about 10hp before the temperature rise might be a problem. if its wound in delta already then you can't do that, but you can cut the coil groups at the midpoint and wire it for 240.


there are ways to wind motors such that you cannot find the midpoint of the coils and connect them for half the voltage though.. so its not always possible.

 

8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• Apr 21, 2018

• #4

What are the chances it was actually rewound with a smaller diameter wire? Pretty high right? I need it to be 15hp.

 

8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• Apr 21, 2018

• #5

Got the end bell off. The three wires go back into the coils and disappear into the varnish mess. Should I just start clipping the ties so I can see what I have? What are the chances I can change this to 220?

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8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• Apr 21, 2018

• #6

Heres what it looks like.

There's a lot of wires tied up around the outside of the bundle.

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rons

Diamond

Joined

Mar 5, 2009

Location

California, USA

• Apr 21, 2018

• #7

Larry Dickman said:

I had a motor a while back that was wound for 440 only. I took it to a motor shop and they converted it to 220v, for about $150.

Click to expand...

They repositioned the splice points.

 

J

johansen

Stainless

Joined

Aug 16, 2014

Location

silverdale wa

• Apr 21, 2018

• #8

it will take some work but it is almost certainly possible to rewire that motor for 220v.

 

8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• Apr 21, 2018

• #9

johansen said:

it will take some work but it is almost certainly possible to rewire that motor for 220v.

Click to expand...

I count 36slots. So 1800 rpm. 4 pole. 12 coils per pole. I have no idea what the arrangement is though. I have not touched any of the connections. Looks like a tough job to me.

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J

johansen

Stainless

Joined

Aug 16, 2014

Location

silverdale wa

• Apr 22, 2018

• #10

you may be able to find the midpoint of each phase (assuming the motor is connected Y) by applying something like 12 or 24 volts between the neutral point and the phase. then look for the connection that has exactly half the voltage on it.

 

8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• Apr 22, 2018

• #11

To do that I will need to pull all the connections out which means I am committed. Still deciding on that one.

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rons

Diamond

Joined

Mar 5, 2009

Location

California, USA

• Apr 22, 2018

• #12

Suggest you get a copy of "Electric Motor Repair" by Robert Rosenberg. You can search for a free pdf copy.

Study the layout of the windings and the connection splice points. You don't have to cut up any wires to do that.

 

8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• Apr 22, 2018

• #13

rons said:

Suggest you get a copy of "Electric Motor Repair" by Robert Rosenberg. You can search for a free pdf copy.

Click to expand...

I have that book.

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L

Larry Dickman

Titanium

Joined

Jan 30, 2014

Location

Temecula, Ca

• Apr 22, 2018

• #14

86turbodsl said:

To do that I will need to pull all the connections out which means I am committed. Still deciding on that one.

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Click to expand...

If you screw with this motor long enough, you just may be committed.

 

8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• Apr 22, 2018

• #15

Well I'm trying to decide if its worth my time. I saw a 15hp motor go at auction for under 50 a couple weeks ago. I can tell this is a good motor but whether its worth screwing with is another story.

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8

86turbodsl

Cast Iron

Joined

Aug 12, 2004

Location

MI, USA

• May 2, 2018

• #16

Closure: I took the motor back to seller and got a refund. He lied about it being 9 wire so he gave my money back.

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