1 to 3 phase static converter motor volt setting

JF in MI

Well-known Member
I picked up a used milling machine which is 440v 3 phase. The motor can be configured to run 220v or 440v. I plan to use a static converter to run it on 220v single phase. My question is; Am I correct in assuming the motor should be configured to the 220 3 phase setting first?
 
Yes, there should be a place on motor that tells which wires to connect together for 220/3phase.

It's been too many moon for me to remember which wires. Also there are 2 types of 3p motors, delta and Y. I don't think a static converter will work on delta motors.

There are smarter people who can better advice.
 
Sure, you would wire the milling machine motor for 220 if you intend to power it with that voltage. I take it you mean your converter has 240 single phase input and can power that 240 three phase milling machine???

John T
 
Yes, it is a '9 wire' motor and there was a very specific "voltage choice" wiring diagram on the back side of the wire junction box attached to the motor.
 
It's been over 40 years since I've worked on converters and 3 phase motors, so what I may remember may not be correct. The wiring diagram will have the wires numbered 1-9. The other ends of wires 1,2 and 3 are connected together making what looks like a Y. The numbers should be in a clockwise direction too. The next set of windings are above the first three. Again, I THINK, they go clockwise, 4,5,and 6. If 1 and 4 are connected, 2 and 4, and 3 and 6. Then 440v would be connected to 7,8 and9, because the windings are connected in series. Now things are foggy. I can't remember how to wire the winding in parallel for 220v.

GOOD LUCK, george
 
I have a lathe with a phase-a-matic ,not sure that is the right brand without looking, and it works fine. I also have a mill with a homemade rotary phase converter. The rotary basically has the same starter as my lathe. If I did it again, I would get a vfd. You get soft start, variable speed, three phase full Power and more. Someone can correct me if I am wrong.
 
Yes, you are correct. My wires are U,V,W, etc. and the diagram is very clear. That is not the issue. My question is; to run on 220 1 ph does the motor need to be changed to 220 (3 ph) or can it be left as is (440 v)? I ask this because I have a neighbor with a Bridgeport that has had a static starter on it for 25 years that has been running fine and he says the motor was and still is wired for 440. I'm wondering if it will still work but maybe with only 1/3rd power or something like that. Other friends who have also run 3 phase motors with a static starter never checked what voltage the motor originally was. They just run it "as is".
 
I understand, but my question is; what voltage are you using and what were (or are now) your machines set up for when you got them 220 or 440? (forget about the phases).
 
I would check pricing on a VFD versus a phase converter. You get the advantage of variable speed and higher efficiency.
 
I actually have looked at a VFD but for the money its the same to just buy a reversible 2HP 220 1 phase motor and swap pulleys. That way all I need to do is plug it into the wall and hit the switch plus I would have a 3 ph mill motor left over to sell on Ebay. The only thing stopping me (besides price difference) is that the pulley is a press fit and I don't want to risk damaging it during removal.
 
I've tested 220v single phase motors using 110v. They ran slower.

I would definately wire the 3 phase motor for 220v when using a static converter. The static converter is, at best, about 70% efficient. So if you need the HP, get the wiring changed.
 
(quoted from post at 21:01:46 10/30/14) There you go.
s it true that out of static(Phase-A-Matic, VFD and rotary phase converters, that only the rotary can handle the instant reverse (plugging) of a lathe?
 
For the money in energy and the noise and hassle of a roto-phase, get a new pulley if you have to!!!
 

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