# Changing rotation on a single phase



## eutecticalloy

Wires 7 & 6 of course.... 

Here is the diagram, so not 7 & 6.


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## stuiec

What is the make and model of the operator?


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## wendon

subelect said:


> I have a question regarding the internal wiring on a single phase motor.
> The job required replacing a very large air-craft hangar style garage door opener motor. 240 volt, single phase, 1 hp, 1755 rpm.
> The starter had both UP/DOWN contactors and a single O/L sensor. The motor was fed with 12/4 SO cord installed by the factory reps.
> Original motor started blowing fuses. The replacement motor arrived and I installed it this afternoon.
> The 12/4 used green for Ground, black and red for constant L1 & L2, white was switched between L1 and L2 to swap rotation.
> The Baldor motor diagram indicated the shaft brake assembly was wired internally from the motor windings.
> Motor wire #1 is direct to L1.
> Motor wire #4 & 5 should be connected to L2.
> Wires #2,3 and 8 are connected together.
> To change direction of rotation, swap 5 & 8.
> I wired the 12/4 so that black fed #1; red fed #4 and white (switched wire) fed #5. Just like the original motor. The new motor works just fine.
> 
> My question if the Run winding is between motor wires 1 and 4, the Start winding must be between 5 & 8, which then has one side connected to 2 & 3.
> If I am only switching motor wire #5 between L1 and L2 to change rotation, what are the other ends of #2 & 3 connected to???? How can this work? I would have thought that I had to switch both #5 & 8, not just one side of the Start winding.
> Obviously, it works just fine, but I can't get the concept in my head correctly.
> Any advice would be appreciated,
> Rick


Don't know how to explain it without drawing it out. It sounds like the motor is a dual voltage motor. The 2&3 connection is kind of like the center tap on a transformer. The start winding could be considered a 120 volt winding. So if you wire #8 to #2&#3 connection, connecting #5 to #4 or #1 will give you 120 volt to the start winding and will reverse the rotation.


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## stuiec

What Eutectic said. Here is an example of how the operator does it. The reversing contactor switches more than just one conductor.

Open:
T1,T3 - L1
T2,T4 - N
T5 - L1
T8 - N

Close:
T1,T3 - N
T2,T4 - L1
T5 - L1
T8 - N


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## wendon

stuiec said:


> What Eutectic said. Here is an example of how the operator does it. The reversing contactor switches more than just one conductor.
> 
> Open:
> T1,T3 - L1
> T2,T4 - N
> T5 - L1
> T8 - N
> 
> Close:
> T1,T3 - N
> T2,T4 - L1
> T5 - L1
> T8 - N


That's a 120 volt connection. I thought the OP said it was a 240 volt.


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## stuiec

wendon said:


> That's a 120 volt connection. I thought the OP said it was a 240 volt.


Oops. It does show 230V connection too, just have to remove a jumper.


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## stuiec

So for 230V :

Open: 

(T4,T8) - L1
T1 - L2
(T2,T3,T5)

Close:

(T1,T8) - L1
T4 - L2
(T2,T3,T5)


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## vietfix

stuiec said:


> So for 230V :
> 
> Open:
> 
> (T4,T8) - L1
> T1 - L2
> (T2,T3,T5)
> 
> Close:
> 
> (T1,T8) - L1
> T4 - L2
> (T2,T3,T5)


This is a good idea. I'll try.


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## subelect

Thanks for the info. I did not consider that there would be two Run windings. 
The opener is a Wilson door from out of Wisconsin; I have the make & model written down in the shop. 
Thanks again for setting me straight,
Rick


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## hardworkingstiff

When I was wiring boat lifts, the controller manufacturer would send their wiring diagram for different types of motors. I would wire it up to the controller schematic and not to the motor schematic. 

I remember thinking it was odd, but it worked.

So, do it the way the controller shows it is what I learned to do.


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