# Replace 3ph Motor With 1ph Motor



## confederatemule (Oct 20, 2015)

I have a 1954 Bridgeport vertical milling machine. It is 3 phase 1 hp. The motor is no good. I am going to replace  the motor with a 220 volt single phase 1 hp motor.

The original motor was removed when I got the machine and I have no idea how to wire the switch to 220 nor how to connect the switch to the single phase motor. 

Can anyone help me?
Do you need more information?

Mule


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## wawoodman (Oct 20, 2015)

A picture of the innards of the switch would probably help. The motor should have the wiring diagram on it, for that connection.

Generally, a switch for 220 requires breaking both of the leads at the switch, unlike a 110 switch. And if it's reversing, that's more complicated. 

Are you hard wiring it, or using a plug?


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## confederatemule (Oct 20, 2015)

It may be Friday before I can get pictures. 

The switch is reversing, so I guess the motor has to be also. I took the original motor to the electrical place where I got the new [used] motor, so he could be sure to get an exact single phase replacement.

I plan to hard wire, although a plug would be more convenient in many ways, not to mention safer in case of an emergency.

Mule


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## wawoodman (Oct 20, 2015)

The switch might have a wiring digram, as well.

With all things electrical, if you aren't comfortable, DON'T DO IT. An electrician costs a lot less than an ER visit, or worse.


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## Ulma Doctor (Oct 21, 2015)

i would recommend the use of twist lock plugs for your situation.
i wish you luck in finding a direct replacement in single phase.
you may need to make an adapter or other modifications to make a single phase replacement work.

Here's an ebay link to another motor, it's 3 phase
http://www.ebay.com/itm/1-HP-BRIDGE...069489?hash=item3d0497e8f1:g:ZvQAAOSwFnFWCeWW

you could get a 110v single phase to 220v 3 phase VFD to power up the unit and install a 3 phase motor in the mill.
that would cost around 160 for the VFD + 400 for the motor(shipped) = 560
if the single phase motor needs extensive modifications and is more expensive than 560,
i'd consider  the ebay motor and VFD, IMHO


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## countryguy (Oct 21, 2015)

I've suggested to others about local Electrician Schools, Vocation trades programs at local colleges,  Even local shops where a friend works have helped me for free sometimes.    I have had replies back on folks that did have success w/ local trade school colleges - So I know that works.        Just a thought that came to mind.


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## kd4gij (Oct 21, 2015)

One of the biggest drawbacks going from 3 phase to single phase is you lose instant reverse. With is really nice for power taping .


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## confederatemule (Oct 25, 2015)

Took longer than I thought, but here are images. 

The old motor 



The replacement motor


The switch. The wires going out of the switch were cut just out side the switch housing.


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