DCCorvette

I am trying to wire up an old bridgeport M-model. It has a 1/2 HP 220/440 3 phase motor. It appears to be set up to run on 440V. I purchased a static phase converter from Grainger Supply. The phase converter will permit mill operation with single phase 220. I understand the wiring and function of the phase converter. However when I opened up the Square D start/switch box on the mill it has a motor starter and coil that I do not understand.

The coil is clearly marked 440V. and it's removeable. Do I need to replace the coil and starter with a 220V unit or will it work with 220 voltage? I also don't no how to switch the motor wiring from 440 to 220. I'm a lost ball in tall weeds. Can anyone help me?
Thanks in advance!

jeff batchelor

I have a bridgeport also. Its a little newer than yours and has a 1hp motor. I just took the wiring coming from the switch box on the mill and wired it to the static phase converter and hit the switch and it fired write up. I did not do anything else. You will lose a little hp using a static phase converter but I have had no problems with mine.

Jeff

NedP1

I have never owned a three phase device, but on other motors making a voltage change from 220 to 110 is fairly easy. There is a small box or a cavity on the motor, usually held on with a couple of screws. The inside of the lid of this has the wiring diagram under it.

I worked with 440 three phase in a plant. 110 volts could be obtained by taking one the 440 three phase wires to ground - that's the way I remember it, but you can check it with a volt meter. Work lights run on the 110 volts and they had me installing a 110 outlet on several machines. Since this has been nearly 40 years I'm a bit foggy on it, but I imagine someone with some current industrial experience will post on here soon. I was what you might call an electricians helper in a publishing plant and my uncle was the lead electrician.

GTR1999

M head, man those are old. I was a Bridgeport service tech for 5 years back in the late 70's. Those were outdated then. The 220 volt 3 ph motors on the J and 2 J heads could be wired either 220/440 volt by following the wire diagram in the motor box cap. For 208 we installed a different motor as you +/-10% rule to follow for amperage.
It sounds like you have a motor starter that will require a correct coil and should have overload protection( heaters) that should be set to the correct amp draw. Can you post a picture?

60vett

Whenever I have ever sold these (I sell used machine tools for a living), I have told the garage mechanic, farmer, whatever that if you only have single phase, take the motor to a motor shop and have it rewound. you'll thank yourself in the long run and it will be easier to resell when you get tired of looking at it. Good luck.

AZDoug

The motor starter and coil is simply a way of closing all three legs of a three phasse circuit by pushing one button.

Rather than trhowing one of those big lever switches like you saw in teh old frankenstein movies, you pusha button, which actived the soleniod coil, which operates the motor contacts. There is also most likely a control tranformer in there so that the voltage the coil and button operates off of is a more safe 110V. This type of system also allows an emergency stop button or limit switches to be wired into the circuit

You really don't need all that stuff for 1/2 HP. My 3 HP mill uses a simple three phase manual rotary switch mounted on the mill head.

Doug

DCCorvette

http://www.phase-a-matic.com/PDF/SIS-2006.pdf This link is the directions I'm trying to follow. I can't figure out which wires energize the magnet starter L1,L2, L3???

AZDoug

Method #1, sequence number 6.

Your coil is for 440 V only, and it will not work. You need either a 220 V coil, or a control tansformer and 110V coil, or buy a manual 3 phase switch and dump the magnetic starter all together, you don't need it.

Doug

juiceman03070

First thing you have to do is change your ''motor taps ''to ....LOW VOLT....
Then 2 legs to the ''addaphase..three wires back to the motor...
The extra leg added is for rotation bump..which you might have to change so forward and reverse match..

DCCorvette

Thanks for all the info. gang I feel bad about putting this kind of post on the forum, but I really need the help.

I changed out the starter coil to a 220 unit and now have the phase converter wired up. Also swapped out the heaters for 220V. Now I need to rewire the motor leads to a 220V configuration. Theres a diagram on the motor for 440 and 220. Theres a total of 9 leads all labled 1-9 and a stop forward and reverse switch with three wires. The switch wires currently go to #'s 1, 2 and 3 motor leads. When I reconfigure the leads for 220 do I put the switch wires back to the same leads or to leads 4,5,6?

Thanks to all!
D.C.

DCCorvette

Thanks to all fired up the bridgeport mill tonight. It works perfectly.