Thread: Rotary phase a matic and Bridgeport questions. Mill is stopping. Help a newb

Hi guys. I am decent when it comes to wiring. I recently got this mill used and it is a 1.5 hp vertical Bridgeport w/ vari drive head. When I bought the mill it was wired and I checked it over as far as fwd, rev, all through high and low gear. The rotary phase converter is a phase a matic 2hp.

Now it's being used in my home shop for some small jobs and I am noticing some things.

While I was machining a decent cut of aluminum the mill basically slowed down and Spindle stopped in place with the cutter getting stuck in the material.

The mill operates as normal. Switch forward and it rotates as planned, same goes for reverse.

I ran the L1, L2, L3 and Ground up to the milling machine switch housing. I connected them as I think they should have benn connected but now I'm thinking that maybe I didn't wire it up right at the switch terminals.

I know when looking at the motors winding in diagrams that you can see the connections at 120 degrees apart and in sequence. What would happen if one of the L#'s is put in place of the other.

For example let's say L1 was wired to switch terminal L1, and L2 wire was put on switch L3 terminal and L3 was put on L2 switch terminal.....what would happen? Would the motor act like horsepower lost but still function correctly in fwd/rev?

It depends on the wires from the motor. 3 or 9 wires at the motor?
Pix will help here.

Agree with hitandmiss... Pictures necessary.
Your rotary may be kicking out 3ph 277 but the mill may be wired and hungry for 3ph 480. I just went through this exact problem with my Wells-Index 747. God knows how long the thing had been wired wrong. I only got suspicious when I was monkeying around with higher RPM's in back gear. I've got a 15hp Phase-a-matic, so there's no shortage of juice, but the mill seemed to be struggling with the torque. Made no sense. So so so much better now. The mill is haaaaaaaaaaaapppy.

Here's the pics...see if you guys can figure it out. The phase converter outputs can be seen coming in the bottom of the switch housing. The wires going out to the motor are leaving out of the top of the swtich housing.

Now tonight when I was taking the pics I noticed when I looked at top of the switch, the white wire was 1st, red 2nd and black 3rd. I looked down at my connections and noticed that the white and black were opposite of above. So I moved them according to the colors above but now my controls are reversed. When in high Range FWD , it goes REV. The photos are of how it look at it current connected state.

I am pretty much thinking that I have my L1, L2, L3's in the wrong order...or I have my colors off before it gets to the converter which is effecting the order at the mill. I will get out there tomorrow and pop off my panel and see if i used Black as L1, Red as L2 and then white out of the Phase Converter as L3.

The color of the wires means nothing for the problem you have, switching the leads around only changes the phase rotation.

First, take the cover off the junction box on the motor, and count splices. You should have 4 splices with 3 wires each. Not 6 splices with 2 wires each.

If you have 4 splices, take a picture of the back side if the drum switch (where the switch contacts are).

If the mill is running in reverse with the switch is in forward, try cutting with the switch in reverse, do you still lack power?
If you now have power, the contacts for forward in the switch are probably burned, (they still can be fixed), need pix to help us "see" what you are looking at.

Here's some more pics.

What I am looking at is 9 black wires coming out of the motor. The switch outputs are connected to three of them. So the Red switch output is connected to one Black going into the motor, the White switch output is connected to one Black going into the motor and the White switch output is connected to one Black going into the motor. What is left after those 3 connections are made is 6 Black wires coming out of the motor. The 6 wires left are split up into 3 pairs (1 Black tied to another Black).

Since you have 6 splices of 2 wires each, the motor is connected for 460 Volts. Look at the motor nameplate in post #4.
The black wires comming out of the motor have wire numbers taped to the wires that are 1-9
When you reconnect, be careful that you don't switch 6 and 9, they normally have a line, or dots under the number.

The switch has some wear, but very usable as it is.

Reconnecting for the lower voltage and swapping phases if it turns the wrong way is all that is needed.

Bill

They have metal tags with numbers. Right now it does look like they had it wired for 460v.
4 is wired to 7
5 is wired to 8
6 is wired to 9
3 is wired to black switch output
2 is wired to red switch output
1 is wired to white switch output

I have removed the wire nuts and separated the wires.
Here's the new connections. Before I turn the power on check them out to see if you agree.......
4-5-6 are wired together with one wire nut
3-9 are wired to L1 switch output (black)
2-8 are wired to L2 switch output (red)
1-7 are wired to L3 switch output (white)

Sound Correct?

"I have removed the wire nuts and separated the wires.
Here's the new connections. Before I turn the power on check them out to see if you agree.......
4-5-6 are wired together with one wire nut
3-9 are wired to L1 switch output (black)
2-8 are wired to L2 switch output (red)
1-7 are wired to L3 switch output (white)

Sound Correct?"


Lookin good. If it don't run smooth, check for a 6 and 9 swap.

Bill

Okay...I tried it out when I got home. The motor came up running in fwd and rev but it needed to swap L1 and L2 because it was bass ackwards.

Now all is good. I will try to do some milling this weekend as I have some plates to machine.

Thank you Bill (hitandmiss) for your help. You learn something new everyday. I was starting to think my mill motor was weak or something was wrong with the drive. I hope this is not the case and that the motor was only getting half the voltage it should have had.