Thread: 12 wire motor wiring problem

Hi guys. Starting a new thread on this topic as old thread has come to a standstill I think. Old thread here:

Graz sag 180 motor wiring problem

for the original questions I asked but now we think this may be a 2 speed motor although I don't think it is. I want 1 speed and want to run off a vfd, sweet and simple. Well I thought it was. Hoping someone with some 2 speed experience can sort this out for me or confirm if it is a 2 speed motor and show me how to wire it up. Thanks

Most machine tool two-speed motors are six-wire "consequent pole", which are single-voltage.

These are operated in parallel Y for high speed and series Delta for low speed.

If a third speed is needed, it will usually be Y and the Delta will have seven wires so it can be opened whenever the Y is being used.

If a fourth speed is needed, it will usually be two seven-wire "consequent pole" windings.

The big problem is the most efficient use of "slot space" without also having to use a horrifically large motor frame size.

So are you saying this is not a 2 spd motor? I'm thinking it isn't also. Would you be able to tell me how to wire it for 220v 3phase? If needed i could let you know which pairs of wires have continuity if that would help. Thanks.

By reading your last thread, there were only two groups of leads that had a circuit. If that is correct, you have a bad motor. As there always has to be a beginning and a end of a coil.

I only checked # 6 and 9 as I Didn't know which one was 6 or 9. I'll check for pairs later today.

Ok i got the pairs all sorted out and also ohm readings.
1 and 2 1.5 ohms
3 and 4 1.3 ohms
5 and 6 1.4 ohms
7 and 8 1.4 ohms
9 and 10 1.4 ohms
11 and 12 1.4 ohms

Hope this helps to figure this out further.

That helps prove it's not a conventionally numbered motor.
Pairs should be:
1 & 4
2 & 5
3 & 6
7 & 10
8 & 11
9 & 12

With all leads disconnected every other combination should read open circuit on a normally numbered 12 wire motor.

What do i do then? Scrap it? Worked on 440 so should work on 220. Hope someone can figure this out as it would be a pain finding another C flange motor to fit.

So since it is a European multi voltage motor, The wire numbering system is not the same as the North American system. And is different yet from the other European dual voltage motors I have worked on.



Now that you have the windings figured out, can you fill in the correct orig. wiring? It looks like a high voltage delta connection, and you need a low voltage delta connection

What I have so far is:

L1 #1 the other end is 2 tied to 3 the other end is 4 going to L3 the other wire to L3 is #? the other end is ?

L1 the other wire is #8 the other end is 7, tied to ?..... There is too many loose ends here!!!! I could Guess alot, but....

The GUESS is:

L1 tied to 1,3,6,8
L2 tied to 5,7,10,12
L3 tied to 2,4,9,11

I would tie a 100-200 Watt/motor HP (all 3 the same) standard light bulb (Not CF, LED etc) in series with each leg from the VFD and the motor, start with creep speed and see what happens..
Worst case you burn out light bulbs! If the lights glow the same, turn up the speed pot, till the motor runs. If one light is a LOT brighter than the others, there is a problem.

Keep us posted,

Bill

Thanks for your help.
Forgot to check original wiring. I'm thinking it was
6+7
2+3
10+11
1+8+L1
5+12+L2
4+9+L3

I haven't bought the vfd yet and am afraid to hook it up and damage the vfd. I guess the light bulbs would work as fuses? I have a 2 hp vfd I could hook up. What do you think? safe?

Most European motors would have there leads make with letter/number combinations like U1, V1...ect. By the number combinations you gave, I would agree that it is a delta connection. But the numbering combinations that you gave, I have never seen before. As you stated, it does work on high voltage, so the winding is good. At this point your better off to take the motor to a electric motor repair shop, and have them ring out the windings.

"I have a 2 hp vfd I could hook up. What do you think? safe?"

We have no idea of the motor size, 5 HP or 15 HP?

Bill

I'm thinking it is around 5 to 6 hp as it draws 16.8@220

macplus has the answer, I'm ashamed I didn't think of it a week ago: the motor works, take it to a motor shop and have them renumber the wires to N.A. standard and you're done, delta, wye your choice at that point.

I think I can get another motor cheaper. There has to be a way to figure this out?

figure this out

It can be figured out, that is what the motor shop is for. When winding a motor there are X amount of coils, and those coils form X amount of groups. Now there is a beginning and a end of a group, lets just say that lead 1 is the beginning of one group and lead 4 is the end of that group. The next group is lead 2 beginning and lead 5 end of group....and so on. In your motor, I have know idea if the beginning are numbered correctly. The other problem is the grouping order, lets say that the first group is 1 and 4, the next group should be 2 and 5, I have know way of knowing that your group wiring is in correct order.
Now..the motor repair shop, should be able to bring up the internal wiring connections on your motor, and trace out the beginning and end of each group and number them correctly in the grouping order as the motor was wound.

Originally Posted by 2rods

There has to be a way to figure this out?

There is. We had to do it at Cat genset school many moons ago, I've never had to do it since and have forgotten the details. It seems we only needed a lantern battery and a meter and about 30 min. of testing,
point is a motor shop could do it in under an hour, shouldn't cost much.

I think it may have been Ugly's or a similar handbook which detailed the technique for identifying ALL the leads assuming that NONE are labeled.

The technique starts out with continuity checks which can, at least, identify pairs of wires.

Then, the technique applies a low-voltage ac signal to pairs of leads and observes the effect, if any, on other pairs of leads. This technique essentially uses the induction motor as a transformer, which it actually is, except that when motoring it is a rotating transformer. So, this part of the testing is using the motor as a static transformer.

There are additional steps, of course, in the general case.

The motor shops don't have a "magic bullet" which solves this issue ... they simply repeat this basic process until everything has been identified.

THEN, they may attach identifying labels and return the motor to you with a substantial bill.

I think we can work this out based on the information available.
to quote
Forgot to check original wiring. I'm thinking it was
6+7
2+3
10+11
1+8+L1
5+12+L2
4+9+L3

to quote

1 and 2 1.5 ohms
3 and 4 1.3 ohms
5 and 6 1.4 ohms
7 and 8 1.4 ohms
9 and 10 1.4 ohms
11 and 12 1.4 ohms


Ok if we assume the motor is delta wound, and was set up 440V, just start walking through the connections that are known
Draw out the basic high voltage delta circut and then go around the triangle, and label the windings as we go

L1 -1-2-3-4-L3-9-10-11-12-L2-5-6-7-8-L1

Ok, thats all six windings in series for high voltage.
The low voltage configuration is to put them in paralell.
So draw out the low voltage circut and see how it works out.

I get

L1 ties to 1, 3, 6, 8
L2 ties to 5, 7, 10, 12
L3 ties to 2, 4, 9, 11

Does that look right to the rest of you?

Thanks ahall. Thats the same pattern another member said. I think I'll try my vfd this way. If something wrong it should fault out hopefully. I'll ramp in slow so there is a smaller draw.