# need help with a 12 lead motor



## micromind (Aug 11, 2007)

I'm not completely sure of this, but I'd be willing to bet that this is a part-winding start set-up. One of the contactors pulls in first, then the other one. Usually the second contactor closes in less than 2 seconds after the first one. 

When the first contactor pulls in, the shaft may or may not turn. The main purpose of the part-winding start system is to reduce the magnetizing current, not the locked rotor current. The magnetizing current is a dead short for the first 1/60th of a second. 

Again, I'm going mostly by basic knowledge of motors here, but my guess is that the motor is a delta connection on low voltage and a wye on high. A lot of foreign motors are this way. 

If so, the high voltage connection would be;

Contactor #1 - L1 = U1; L2 = V1; L3 = W1; U2, V2, W2, are spliced.

Contactor #2 - L1 = X1; L2 = Y1; L3 = Z1; X2, Y2, Z2, are spliced. 

This can be verified by a simple continuity check of the windings. With all motor leads disconnected, there should be continuity between U1 and V2; V1 and W2; W1 and U2. Also, X1 and Y2; Y1 and Z2; Z1 and X2. 

Are both contactors fed from the lines? If so, then it is certainly part-winding start. If not, then ignore the above connections; they would be wrong.

Again, the above is not absolute truth, but when I made a drawing of the windings and labeled them, it made sense.

Rob


----------



## Jlarson (Jun 28, 2009)

Edit, never mind I screwed up.


----------



## ArcRedoubt (Jun 14, 2011)

yes they are fed right from a junction block

That is making a lot more sense to me, i saw this setup for a moment and was called away on an emergency at another jobsite. I need to have some idea of what to look for, believe you've provided it. The Chinese diagram has several typos ( Low volts and "Hing" volts connection headings) and is partially destroyed. The control cabinet has a couple of funky looking timers in it too. And now i'm having epiphany as I type because am seeing a parallel with some of the other motors there that were smaller 6 post motors with bridge shunts.

Thanx Micro, sometimes it just takes a little push to get me going in the right direction, and then i'm off to the races


----------



## RIVETER (Sep 26, 2009)

ArcRedoubt said:


> I am currently changing 3 phase part winding motors in some used woodworking machinery from low volt to high volt. no big deal until I got to this "SEING" brand 30hp/22kw that was hooked up weird and has bizarre labeling on the leads.
> 
> It is a 12 lead motor that has leads labeled UVW and XYZ , each letter has two leads, for example U1 and U2, V1 and V2, etc. This motor uses 2 starters across the line to run, I am assuming one cuts out as the other cuts in, externally switched star start, delta run arrangement.
> 
> ...


We all have to be honest with each other here. You knew the answer before you presented it to the forum...right? If you did not you should not have taken the job...right?


----------



## ArcRedoubt (Jun 14, 2011)

to be strictly honest, knowing and remembering stuff I rarely use is more of a problem than it used to be............ ; )

I am after all, only new to this forum.

and besides all that, being ignorant never slowed me down too much as long as I knew who to ask for help!


----------



## MDShunk (Jan 7, 2007)

ArcRedoubt said:


> and besides all that, being ignorant never slowed me down too much as long as I knew who to ask for help!


Right on :thumbsup:


----------



## nitro71 (Sep 17, 2009)

Without a wiring diagram on the motor most of us would have some problems. I'd be on the phone with made in China motors trying to get an answer. Then I'd post on here after doing some web research.


----------



## ArcRedoubt (Jun 14, 2011)

nitro71 said:


> Without a wiring diagram on the motor most of us would have some problems. I'd be on the phone with made in China motors trying to get an answer. Then I'd post on here after doing some web research.


Yup, 'cept my Chinese is a little rusty. Called local motor shop wizard, he's doing a drive-by this morning on his way to another service call, he's got a source reference that he wants to give me. That is what I really would like to have, can't have too many books.

There isn't anything that can't be resolved, minimizing the time involved is the REAL trick.


----------



## retiredsparktech (Mar 8, 2011)

I don't know if citing a competitive web site is wrong, but if you look at ECN a member known as Scott35 has a lot of informative diagrams listed there. you might be able to determine the relationship between NEMA and ISO.


----------



## Motorwinder (Dec 30, 2010)

Sorry if I'm late for a reply.

motor leads marking as follows. A phase X1=1, X2=4, U1=7, U2=10/ B phase Y1=2, Y2=5, V1=8, V2=11 / C Phase Z1=3, Z2=6, W1=9, W2=12

Hope this helps.


----------

