Missing motor lead numbers.

[electrofelon]

I've got a 20 HP motor, dual voltage but I need 230V. The common bundle is still connected (4,5,6). But I can only make out one number on the other 6. Data plate shows (L1, 1,7) (L2, 2,8) (L3, 3,9). How can I identify the missing numbers?

Thanks

 

[gadfly56]

I've got a 20 HP motor, dual voltage but I need 230V. The common bundle is still connected (4,5,6). But I can only make out one number on the other 6. Data plate shows (L1, 1,7) (L2, 2,8) (L3, 3,9). How can I identify the missing numbers?

Thanks

I'm guessing something as esoteric as the installation manual is not available?

 

[infinity]

Since you already know 4-5-6 you should be able to get a wiring diagram for a 9 lead motor and see what pairs go together on each winding. Then you can use an ohm meter to ring out the pairs. What you have is a low voltage, Wye configuration.

 

[electrofelon]

Since you already know 4-5-6 you should be able to get a wiring diagram for a 9 lead motor and see what pairs go together on each winding. Then you can use an ohm meter to ring out the pairs. What you have is a low voltage, Wye configuration.

Thanks Rob, I think I can get it now. I have the wiring diagram, but not the Y part of it you posted, which clears up how it is connected. I can ring it out now.

 

[infinity]

Thanks Rob, I think I can get it now. I have the wiring diagram, but not the Y part of it you posted, which clears up how it is connected. I can ring it out now.

 

[electrofelon]

Apparently parallel and wye at the same time was too much for my primitive electrician brain to handle.

 

[Jraef]

That diagram left out part of the picture; when connected for Low voltage, it is Y-Y, or "parallel Y". Here is a better depiction:

Sonce you already have 4, 5 and 6 connected together, yours is already set up for Low votlage

 

[electrofelon]

That diagram left out part of the picture; when connected for Low voltage, it is Y-Y, or "parallel Y". Here is a better depiction:

Sonce you already have 4, 5 and 6 connected together, yours is already set up for Low votlage

Yeah, I was able to put it together from the two diagrams, but nice diagram, thanks.

Some cringers broke in and stole the wire to the elevator motor. They didn't cut off the lead wires, but I can only see the "9"

 

[electrofelon]

Don't I need to match up the "starts" and "ends" of the parallel coils?

 

[MD Automation]

Maybe I am missing something , but I think it’s not as easy as simply ringing out windings.

If you can identify the 4,5,6 wires then finding the 1,2,3 wires should be easy. I know you said the 4,5,6 connection is still together, but not sure if you can ID 4,5,6 individually?

When you mention the “other #6", I suppose you are talking about the #9 wire?

Anyway, you should be able to use an ohmmeter to find 3 pairs of wires that have continuity only between themselves (1-4), (2-5) & (3-6).

The remaining 3 wires (7,8,9) should also have continuity between any pair of them (7-8, 8-9, 7-9).

But the trick is knowing which of those three is the 7, 8 and 9.

There are plenty of videos on the web about how to use a 6 volt battery and voltmeter to find that out.

Something like this...

You flash 6 volts across (for example) 8 and 9, which is the lower part of the inner “Y” in Jraef’s diagram. When you do that, the voltage measured on the 1-4 winding should be quite small since it is the farthest “away” vector wise. The measured voltage on the 2-5 or 3-6 windings will be higher since those windings are inline with one of the 2 lower windings across 8 and 9. So they will induct much more than 1-4 when you magnetize the 8-9 pairs.

So put a voltmeter on the 1-4 winding and then find out which pair of the 7,8,9 wires gives the smallest reading when you briefly hit that pair with 6 volts. Those 2 should be 8 and 9 – but you don’t know which is which yet. (Well, maybe you do know #9 if it’s marked).

Now repeat the same experiment except measure the 2-5 winding. When you find the pair inside 7,8,9 that you hit with the battery that gives you the smallest reading on 2-5, that pair is the 7 and 9. Now you can figure out which is the 7, the 8 and the 9.

1000 pardons if I am making it more confusing than it needs to be!

Edit:
The videos on the web like the one above are meant to help when you don't know any of the wires. In your case, you are already halfway there, and since you know the 4,5,6 connection, your polarities are also OK. The 1,2 and 3 should be easy with a ohmeter. The trick is just really figuring out which is the 7,8 and 9 wires.

 

[Hv&Lv]

4,5,6 are tied now and you can make out 9.
untie them, ring out and label 1,2,& 3.
you see 9, the other two are 7,8

50-50 chance?

 

[Bluegrass Boy]

I've got a 20 HP motor, dual voltage but I need 230V. The common bundle is still connected (4,5,6). But I can only make out one number on the other 6. Data plate shows (L1, 1,7) (L2, 2,8) (L3, 3,9). How can I identify the missing numbers?

Thanks

Take a close look at the insulation on each wire, a lot I have seen have the numbers on each wire. Some are hard to read, get a flashlight, if dirty, give them a wipe , may get lucky.

 

[Greentagger]

Take a close look at the insulation on each wire, a lot I have seen have the numbers on each wire. Some are hard to read, get a flashlight, if dirty, give them a wipe , may get lucky.

Becareful with the wipe , lest you wipe them off.

 

[electrofelon]

Maybe I am missing something , but I think it’s not as easy as simply ringing out windings.

If you can identify the 4,5,6 wires then finding the 1,2,3 wires should be easy. I know you said the 4,5,6 connection is still together, but not sure if you can ID 4,5,6 individually?

When you mention the “other #6", I suppose you are talking about the #9 wire?

Anyway, you should be able to use an ohmmeter to find 3 pairs of wires that have continuity only between themselves (1-4), (2-5) & (3-6).

The remaining 3 wires (7,8,9) should also have continuity between any pair of them (7-8, 8-9, 7-9).

But the trick is knowing which of those three is the 7, 8 and 9.

There are plenty of videos on the web about how to use a 6 volt battery and voltmeter to find that out.

Something like this...

You flash 6 volts across (for example) 8 and 9, which is the lower part of the inner “Y” in Jraef’s diagram. When you do that, the voltage measured on the 1-4 winding should be quite small since it is the farthest “away” vector wise. The measured voltage on the 2-5 or 3-6 windings will be higher since those windings are inline with one of the 2 lower windings across 8 and 9. So they will induct much more than 1-4 when you magnetize the 8-9 pairs.

So put a voltmeter on the 1-4 winding and then find out which pair of the 7,8,9 wires gives the smallest reading when you briefly hit that pair with 6 volts. Those 2 should be 8 and 9 – but you don’t know which is which yet. (Well, maybe you do know #9 if it’s marked).

Now repeat the same experiment except measure the 2-5 winding. When you find the pair inside 7,8,9 that you hit with the battery that gives you the smallest reading on 2-5, that pair is the 7 and 9. Now you can figure out which is the 7, the 8 and the 9.

1000 pardons if I am making it more confusing than it needs to be!

Edit:
The videos on the web like the one above are meant to help when you don't know any of the wires. In your case, you are already halfway there, and since you know the 4,5,6 connection, your polarities are also OK. The 1,2 and 3 should be easy with a ohmeter. The trick is just really figuring out which is the 7,8 and 9 wires.

MD, right I see what you are saying. Yes 4,5,6 are bundled AND I can see the numbers, so I an ring out 1,4 2,5 3,6. #9 is labeled. So it's just a matter of 7 and 8. I will take a closer look tomorrow. There is a belt shroud in the way I haven't taken off yet so I will be able to see a little better

 

[MD Automation]

Ethan - good luck tomorrow. Will cross my fingers for you that you can find a 7 or 8 wire marking somewhere. As Hv&Lv pointed out above, you likely can be confident in everything else with a simple ohmeter, it's just 7 and 8 to figure out.

 

[kwired]

Been a long time since I have had to do it, think I have notes somewhere but not sure where on how to do it.

I know you can find the 7,8,9 easily as those three have continuity to one another, also can find the right pairs for 1-4, 2-5 and 3-6 with continuity tests, you just don't know which polarity is correct if none are marked or if only very few are marked.

Method I am thinking of is to apply low volts to your 7,8,9 (uncoupled motor) even if you don't know which is which. It will run on just the one set of windings this way. Then the rest of the process is what I would need to find the notes for the details, but you can take measurements of the non connected leads to determine how to connect them.

If you are down to just say not knowing which is 1 and which is 4 you can connect it up for applied volts (uncoupled motor again) and if that one coil seems to be "bucking" try swapping the connection of those two leads and it likely is now in proper sequence. I would think not knowing 7 and 8 would be similar, if currents don't balance try swapping the two leads and it likely will.

 

[gadfly56]

Ethan - good luck tomorrow. Will cross my fingers for you that you can find a 7 or 8 wire marking somewhere. As Hv&Lv pointed out above, you likely can be confident in everything else with a simple ohmeter, it's just 7 and 8 to figure out.

If he's in NY state, wish him luck finding his car tomorrow (Thur). We are looking at up to 2 feet of snow.

 

[electrofelon]

If he's in NY state, wish him luck finding his car tomorrow (Thur). We are looking at up to 2 feet of snow.

Looks like they are saying 10 inches at home. I'm an hour west of Albany. But, I am in Seattle currently!

I got it figured out. After taking the motor out and the peckerhead off, I was able to make out most of the numbers. The only ones I wasn't sure of were 1and 7 but they go together anyway.

 

[kwired]

Been a long time since I have had to do it, think I have notes somewhere but not sure where on how to do it.

I know you can find the 7,8,9 easily as those three have continuity to one another, also can find the right pairs for 1-4, 2-5 and 3-6 with continuity tests, you just don't know which polarity is correct if none are marked or if only very few are marked.

Method I am thinking of is to apply low volts to your 7,8,9 (uncoupled motor) even if you don't know which is which. It will run on just the one set of windings this way. Then the rest of the process is what I would need to find the notes for the details, but you can take measurements of the non connected leads to determine how to connect them.

If you are down to just say not knowing which is 1 and which is 4 you can connect it up for applied volts (uncoupled motor again) and if that one coil seems to be "bucking" try swapping the connection of those two leads and it likely is now in proper sequence. I would think not knowing 7 and 8 would be similar, if currents don't balance try swapping the two leads and it likely will.

Note: Current unbalance possibly severe enough it fails to start or draws very heavy current, enough it likely won't be instantaneous trip of SC/GF device, but likely will trip in rather short time.

 

[kwired]

Looks like they are saying 10 inches at home. I'm an hour west of Albany. But, I am in Seattle currently!

I got it figured out. After taking the motor out and the peckerhead off, I was able to make out most of the numbers. The only ones I wasn't sure of were 1and 7 but they go together anyway.

With all leads disconnected 1 has continuity to 4 and 7 has continuity to 8 and 9.