Any electricians on here?

[racerone3]

I've been scouring the net and can't find anything useful, so I will do what I usually do and turn to 6x6 world

Let me start off by saying that I have a real good handle on 12V negative ground, but know slightly less than enough to be dangerous when it comes to 120v or 220 wiring. (IE: nothing I've done is up to code, but I haven't burned anything to the ground... yet)

Bought a lathe last week that is 220v 3 phase. Of course I don't have a 3 phase service to my shop. Did some research and bought a static phase converter. It came in today and I hooked it up following the schematic.

first test, with the switch in forward the motor would work in reverse. with the switch in reverse, nothing.
(internet research told me to switch any two wires to change motor direction)
test two, with the switch in reverse the motor would work in reverse. switch in forward, nothing.
test three (swapped 2 different wires) switch in reverse motor runs forward, switch in forward nothing.

those tests tell me that the switch is working on both sides... Everything worked right on the Lathe last week when I tested it before buying (from a highly trusted source)

with the lathe able to run in forward, I can now do most things I need to, but if I need reverse I would have to crawl behind and switch wires... not to mention I would like it to be right!

anyone have any clue what the issue might be?

[Beeman]

Yes, switching any two phases will cause the motor switch direction.

Sounds like your switch is to blame, possibly a bad connector on the switch. Do you know what kind it is? Link? A 3 phase motor can run on 2 phases.. but not in a safe or practical way.

You can test it with a voltmeter capable of 220V, on the motor side and on the supply side check the voltage across each lead. In either the forward or reverse direction the voltage should be pretty much the same between any of the three hot wires on one side.

[racerone3]

all connections in the switch are working. traced them for continuity and they work according to the diagram inside the switch cover. all worked fine last Sunday when I picked up the lathe ( was hooked directly to a 3 phase service). I was pondering switching 2 wires inside the phase converter instead of switching them at the motor. would that do anything??

[Beeman]

Then I'd try testing the voltage as stated in my edit on my first post. Changing the wires on the converter won't do anything.. unless - are you running 4 wires + ground from the phase converter? Motor is 3 wires right?

[racerone3]

thanks for pointing me to your edit, or I might have never found it. I will check that in the morning (if I have my good meter here) I have 2 hot leads from the breaker and a ground run to the converter, then 3 hot leads and a ground down to the lathe. once the wiring goes into the lathe I have no clue where it goes. I would expect that one leg would go straight to the motor, and the other 2 to the switch capable of reversing polarity but I'm not entirely sure that is the case. I will probably unhook everything tomorrow and trace wires to see exactly what's going where.

If one of the connections at the motor worked loose in transport could it be running on 2 legs and cause the issue I'm having?

[Mike]

It sounds like you bought a bad lathe. I'm kidding. What brand and size phase converter did you get? If one of the legs was disconnected on the motor, it would basically be running off of single phase power at a higher current and you would probably notice the motor not starting smoothly or at all.

When it does start to run, does it turn smoothly? Like Beeman said, the meter will be your best bet to quickly see what's going on and eliminate the motor or the convertor quickly.

[racerone3]

converter is from Western NY Supply (Damn yankee converter). It is rated for 1 to 3 hp motors.

Motor turns smoothly, and I've been able to do some work with the lathe, so the single phase is probably ruled out. I will dive into it with a meter tomorrow and report back with my findings

[Beeman]

If one of the connections at the motor worked loose in transport could it be running on 2 legs and cause the issue I'm having?

Possibly, but I'm not sure if a motor can be reversed and forwarded on 2 phases by switching the leads - something that might make phase loss possibility less likely. You can check out this link for some interesting reading material -> SSAC Motor Protectors Technical Help 1-800-377-SSAC (7722)

[Mike]

I was hoping to look at the wiring diagram to see which legs were being passed through the converter but I didn't see one online for that model. It doesn't matter though I just wanted to point out one thing when you go to test the converter: Most static converters only apply three phase power during motor starting (typically .5 to 1.5 seconds). After that, one leg will drop out and only two of your conductors will be hot. So when you go to test it, just keep that in mind. I didn't want you to see a dead leg and think that the converter wasn't working properly.

[Model Citizen]

Whip & I are going riding this morning, so no time to go into detail, but what you needed was a rotary 3 phase converter, not a static 3 phase. You will never get the lathe to work right with the wrong converter. There's a big difference in price between a rotary & static, but like Whip always says, you get what you pay for. Just want to help you out before you burn your garage.

Bridget

[racerone3]

got it working correctly!

after reading everyone's replys, and some conversation back and forth with Thebuggyman (Thanks Jim!) about the difference between true 3 phase, and the "3 phase" you get from a converter, I was pretty sure that the right combination of wiring would fix the problem. All 3 wires inside the lathe are Red, so I labeled them 1-2-3. Then I made a chart with every possible combination. (6)
IE: 1-Green, 2-Black, 3-White. I tried each combination starting with what was already hooked up and recorded what worked and what didn't with each combination. on the 3rd try, both switch positions worked, but in the wrong direction. Of course the last combination on my chart was the one that worked.

Like everything that gets wired in the shop, I will monitor it closely and turn off the breaker when not in use till I'm convinced that things are working as they should

[Beeman]

Like everything that gets wired in the shop, I will monitor it closely and turn off the breaker when not in use till I'm convinced that things are working as they should

- I did the same when I ran the gas line to my shop and installed the heater. Even though it was done right, there's that startup feeling that you need to be around when it's running to make sure the place doesn't burn down (It passes through the test of time of course) :P

Good work!! I'm glad you got it sorted out!

[whipper-ag]

Glad you got it running. Should be fine for light duty turning. You'll probably only notice the loss of power on heavy cuts. You're going to love being able to make your own stuff at home.

Whipper

[racerone3]

From what I've read, the converter should drop the hp of the motor by 1/3. that sucks, but it sure beats not having a lathe in the shop! If I get into anything too big, I can always haul it to work and use the big lathe there.

now I need to get some tooling! I bought a cheapie tool post off ebay to get going and had to modify it to work with the cutters that I have.

[thebuggyman1]

got it working correctly!
Of course the last combination on my chart was the one that worked.

You should have started at the bottom of the list.