# Changing Part winding to Delta connected motor



## Handasee (Dec 18, 2009)

I have to connect a used 100HP 575 Volt 1780 rpm dust collector motor. This motor has been rewound from the original specifications. No connection diagram for the new windings. This is a 12 lead motor. The leads have been grouped together (but not connected) as follows, leads,1&6....2&4....3&5....7&12....8&10....9&11.
This tells me that the motor was set up for Part winding starting with two delta windings in parallel. 
The new setup will use a CH soft start.
If this was a part winding starting motor then I believe the run connections would be L1 to 1&6&7&12,...L2 to 2&4&8&10,....L3 to 3&5&9&11.
My motor shop suggests that I connect the motor as a standard 12 lead delta motor with the following connections, L1 to 1&12,...L2 to 2&12, L3 to 3&11, and 4&7.....5&8....6&9.
Does anyone have experience with this changeover?
Which connection is best?


----------



## don_resqcapt19 (Jul 18, 2010)

How do those connections indicate a part winding start? To me they indicate a dual voltage motor connected for low voltage. The connections from the motor shop suggest a connection for the higher voltage.


----------



## Handasee (Dec 18, 2009)

don_resqcapt19 said:


> How do those connections indicate a part winding start? To me they indicate a dual voltage motor connected for low voltage. The connections from the motor shop suggest a connection for the higher voltage.


The motor is rated for 575 Volts. I was able to talk to the person that pulled the dust collector from the old plant and he confirmed it was 575 volts. 
The grouping of the leads that I originally posted was done by a rewind shop.
The tape used was not the type an electrician would have readily available. 
I see what you are implying. My problem is to confirm one or the other.


----------



## micromind (Aug 11, 2007)

Since the motor was rewound for 575, and it'd 12 lead, there are only two ways it was done. 

All 12 lead motors are dual voltage. The rewind could have been for 288/575 or 575/1150. Of course, neither 288 or 1150 exist, so the question is whether 575 is the low voltage connection or the high. 

All 12 lead motors can be part-winding started on low voltage only. Therefore, there would be no useful reason to wind it 288/575. I strongly suspect it is wound 575/1150. 

One way to know for sure would be to connect it for high voltage, blast it with some 575 and see what happens. If it is indeed wound 575/1150, it will produce about 1/3 of its normal HP. Since it is driving a blower, it won't come up to full speed, but as long as it isn't run for more than a few minutes it won't be damaged. The current when starting will be around 200-300 amps, maybe less.

If the above test proves true, re-connect it for low voltage. It should start up more like normal, and the starting current will be 500-600 amps. Running current will be around 95 or a bit less. 

Rob

P.S. The part-winding connection is....L1=1&6, L2=2&4, L3=3&5 for starting, L1=1,6,7,12; L2=2,4,8,10; L3=3,5,9,11 for run.


----------



## don_resqcapt19 (Jul 18, 2010)

Not sure if there is a common system that would supply 287 volts, so with 12 leads this may be intended for wye start, delta run. I guess you would have to go with what the rewinding shop says.


----------



## Motorwinder (Dec 30, 2010)

Your connection is right. This is a 12 lead, single voltage motor. They are normally delta run motors. 
The reason manufactures make 12 lead, single voltage motors, are so you can use part winding start, or wye-delta start. So if you're running a soft starter, your connection is right.

The easiest way to tell is, if it has only one voltage rating on the name plate.

Edit: Your connection, not the motor shops.
1,6,7,12 / 2,4,8,10 / 3,5,9,11

this post is old, so you probably already know this..


----------

