# Installing Switch In Reversing AC Motor



## micromind (Mar 9, 2008)

There are 3 individual windings in this motor. Two of them are run windings and the other is the start winding. 

The two run windings are identical. This motor is dual voltage; it can be run on 115 or 230. When it's connected for 115, the two run windings are connected in parallel. If it's 230, they're in series. The start winding simply piggy-backs one of the run windings.

The direction of rotation is determined by the relationship of the start winding to the run windings. 

The start winding is 5 & 8. If it is connected 5 with 3 and 8 with 4, the shaft will turn CW when viewed from the non-drive end. If 5 is with 4, and 8 is with 3, it'll turn CCW. 

If you want a switch to reverse the rotation, you'll need a two pole double throw toggle switch that's rated for at least 10 amps. It's an easy connection.

If interested, write back and I (or one of the others around here) will provide the connections.

Rob


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## AllanJ (Nov 24, 2007)

Are you supposed to turn the motor off and wait for it to stop before flipping the reversing switch?

Seems to me that powering it in reverse while it is still going the other way will cause a tremendous power draw, enough to burn out a switch before tripping a breaker down in your panel.


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## micromind (Mar 9, 2008)

If the reversing switch is flipped while a single phase motor (like this one) is running, nothing will happen. It'll keep running in the same direction as it was. It will turn the other way only after it has been de-energized and slowed down enough to engage the start winding. 

A 3 phase motor that is reversed while running will instantly reverse. This is called plugging. Some motors (like the ones in cranes) are specifically designed for this.


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## RetiredLE (Jan 24, 2011)

AllanJ said:


> Are you supposed to turn the motor off and wait for it to stop before flipping the reversing switch?


Good point. I am not sure if that would have been an issue or not, but I did not attempt to reverse the motor until it had stopped completely. 



> If you want a switch to reverse the rotation, you'll need a two pole double throw toggle switch that's rated for at least 10 amps. It's an easy connection. If interested, write back and I (or one of the others around here) will provide the connections. Rob


Definitely interested. Perhaps a diagram/drawing would help me get the picture if you will.


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## RetiredLE (Jan 24, 2011)

Bump.


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## micromind (Mar 9, 2008)

A couple of questions; 

1) What voltage is the motor to be operated at?

2) How will the reversing switch be mounted? A toggle switch is best mounted in the cover of a handy box, but there are other ways. 

3) Is there an on-off switch ahead of the reversing switch? There are two types of switches, one is just forward and reverse, the other has a center off position. 

4) Does the power feed come to the switch box first then to the motor, or does it go to the motor and a separate cable goes to the switch box? In either case, you'll need 4 wires plus a ground from the motor to the switch box. It's easier to run the power to the switch box then to the motor. 

5) Are the motor leads identified P1, P2, T2, T3, T4, T5, and T8? I suspect they are; if not, post the numbers or colors. 

6) Are there 7 lead wires in the motor box, or is there a terminal board that they connect to? 

I don't have the computer skills to post a diagram, but given the answers to the above, I can tell you which motor lead wires go to which terminals on the switch. 

The switches I'm thinking of are Grainger part # 1XWR4 and 1XWR7. Go to www.grainger.com and type the numbers into the search box. 

One slight negative about using the switch with the center off position is it's really easy to accidentally bump it and start the motor.


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## RetiredLE (Jan 24, 2011)

> 1) What voltage is the motor to be operated at?


110



> 2) How will the reversing switch be mounted? A toggle switch is best mounted in the cover of a handy box, but there are other ways.


I am flexible in that regard. Probably next to the power switch. 




> 3) Is there an on-off switch ahead of the reversing switch? There are two types of switches, one is just forward and reverse, the other has a center off position.


Yes there is. There is a main power switch under the front of the table. The motor power cord plugs into a receptacle, which is included in that switch housing so when the switch is thrown, power is sent to the motor. 




> 4) Does the power feed come to the switch box first then to the motor, or does it go to the motor and a separate cable goes to the switch box? In either case, you'll need 4 wires plus a ground from the motor to the switch box. It's easier to run the power to the switch box then to the motor.


The power comes into the main switch first. The electrical cord from the motor plugs into that. 



> 5) Are the motor leads identified P1, P2, T2, T3, T4, T5, and T8? I suspect they are; if not, post the numbers or colors.


Yes they are. The wires are all yellow.




> 6) Are there 7 lead wires in the motor box, or is there a terminal board that they connect to?


There are 7 yellow wires that come out of the motor housing – which is covered by a small metal plate with two screws holding it on. 




> I don't have the computer skills to post a diagram, but given the answers to the above, I can tell you which motor lead wires go to which terminals on the switch.
> 
> The switches I'm thinking of are Grainger part # 1XWR4 and 1XWR7. Go to www.grainger.com and type the numbers into the search box.


Will do. The 1XWR7 switch looks like the one that was fried. 



> One slight negative about using the switch with the center off position is it's really easy to accidentally bump it and start the motor.


A solution to that would be to mount it in a spot where it wouldn’t be likely to be accidentally bumped. Or perhaps install a cover over it.


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## micromind (Mar 9, 2008)

Since there is an existing power switch, the 1XWR4 would work best. It has two positions; forward and reverse. The motor will be turned on and off with the power switch. 

As I see it, there is a cord with a plug coming from the motor to a switched receptacle. Is there another cord from the motor to the reversing switch? If so, how many wires and what color? 

There are two choices as to how to mount and wire the reversing switch. It can be mounted somewhere in line with the motor cord, and this cord will need to be cut; both ends will go into the reversing switch box, plus one more two wire cord from the motor to the reversing switch box. 

The other way is to leave the motor cord as it is, and run another 5 wire cord from the motor to the reversing switch box. The 5 wire cord can be one 3 wire plus one two wire. 

Once we pick how we'll mount the reversing switch box, wiring it will be easy.


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## RetiredLE (Jan 24, 2011)

> Since there is an existing power switch, the 1XWR4 would work best. It has two positions; forward and reverse. The motor will be turned on and off with the power switch.


Ok so far.



> As I see it, there is a cord with a plug coming from the motor to a switched receptacle. Is there another cord from the motor to the reversing switch? If so, how many wires and what color?


No cord to the reversing switch. The switch that was in there was wired to some of the yellow wires. Not sure which ones now. 




> There are two choices as to how to mount and wire the reversing switch. It can be mounted somewhere in line with the motor cord, and this cord will need to be cut; both ends will go into the reversing switch box, plus one more two wire cord from the motor to the reversing switch box.



Sounds too complicated. 




> The other way is to leave the motor cord as it is, and run another 5 wire cord from the motor to the reversing switch box. The 5 wire cord can be one 3 wire plus one two wire.


 

Lets try that. 




> Once we pick how we'll mount the reversing switch box, wiring it will be easy.


Ok Dr. what's the next step?


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## micromind (Mar 9, 2008)

The following will assume that a cord is already connected to the motor and is controlled by a switch.

You'll need 5 wires from the motor to the reversing switch. This can be a 3 wire cord plus a two wire one, or two 3 wire ones. If you use two 3 wire cords, simply tie both green wires to ground at the motor and the reversing switch box. The cords can be 16 gauge or larger. 

You'll need some sort of a box to mount the reversing switch is. A basic metal single-gang handy box will do. If you use this, you'll need a metal cover plate. Get the one with no knockout; it'll be smooth and have no stamped hole. Drill a 1/2" hole in the center of the cover plate, and mount the switch in it. Use the 1XWR4 switch or equal. It's a two-pole double throw. 

Now, for the actual wire connections.

I will omit grounds since they go to the frame of the motor and screw to the reversing switch box.

The black wire of the incoming power will go to motor lead P1. It very likely is already there. 

Now, we'll call the 3 wire cord from the motor to the reversing switch box 'cord A'. The other cord (either two or 3 wire, just depends on what you get) we'll call 'cord B'. 

The black wire of cord A goes to motor wires P2 and T3. An orange or yellow wirenut will work for the splice here. 

The white wire of cord A goes to motor wires T2 and T4. The white wire of the incoming power goes here too. You'll have 4 wires in this splice. Use a yellow wirenut, an orange one can't handle 4 wires.

The black wire of cord B goes to motor wire T5. An orange wirenut will do fine here. 

The white wire of cord B goes to motor wire T8. 

Now for the reversing switch.

The switch has 6 terminals, hold it so you're looking at two vertical rows of 3 terminals. 3 terminals on the left and 3 on the right. 

The black wire of cord A goes to the left center terminal. The white wire of cord A goes to the right center terminal. 

The black wire of cord B goes to the bottom left and the top right. The white wire of cord B goes to the bottom right and top left. 

Put the covers on and you're done.

When the motor is started with the reversing switch in one position, it'll turn one way. When it's started with the switch in the other position, it'll turn the other way. If the reversing switch is flipped while the motor is running, nothing happens. It just keeps running in the same direction. It'll simply turn the other way when it's started next time. No damage at all. 

P.S. I'll be working out of town Thursday and Friday; I'll check back sometime Saturday.


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## iaredoug (Dec 22, 2012)

Is the wiring the same for the 1xwr7?


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## micromind (Mar 9, 2008)

iaredoug said:


> Is the wiring the same for the 1xwr7?


Yes it is.


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## jaylaforte (Feb 2, 2013)

Micromind - This thread was monumental in helping me wire my Dayton motor to power my grain mill for homebrewing. Thank you very much for taking the time to write up these instructions.

I do have one question for you - My toggle switch works perfectly for forward and reverse but trips the breaker when it's in the center position. Is this normal? I know the easy answer is to not switch it to the center when powered but I'm just curious what's going on...

Thanks!


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## Camano (Oct 26, 2014)

*Reversing switch 120 AC motor*

Used a double pole double throw switch.. wired as described. works as it should when switch is in either of the two on positions. motor humms when switch is in the center position... any thoughts?
Thank you.
Camano


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## dmxtothemax (Oct 26, 2010)

The reversing switch is used to reverse the wires to the field windings only,
With the switch in the centre off position,
You probably have nothing going to the field windings !
But power could still be going to the armature !
Hense the humming.


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## micromind (Mar 9, 2008)

Camano said:


> Used a double pole double throw switch.. wired as described. works as it should when switch is in either of the two on positions. motor humms when switch is in the center position... any thoughts?
> Thank you.
> Camano


There are two windings in a motor, start and run. 

To reverse rotation, the start winding needs to be swapped and the run winding stays the same. 

The switch connection I described doesn't effect the run windings, only the start. So, with the switch in the off position, the run winding is still energized, but the start winding is not. 

Without the start winding energized, the motor doesn't know which way to turn, so it doesn't turn at all.


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## Camano (Oct 26, 2014)

*what would you do?*

Seems odd to have the motor humming when it's off...
my preference would be it is not energized when off, (switch in center position) and able to forward or reverse when switched... is there an alternative way to wire it? or different kind of switch that would be a better fit?
Thank you for your help..


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## micromind (Mar 9, 2008)

To get the motor to turn off when the switch is in the center position, you'll need a 3 pole double throw switch. Since it's now the controller, it'll need to be rated for the HP of the motor. 

Orient the switch so you're looking at the back (9 terminals), and the toggle (facing away from you) moves up and down, not side to side. 

Connect the wires to the right hand side of the 3 pole switch exactly as the right hand side of the two pole switch. Connect the wires to the left hand side of the 3 pole switch exactly as the left hand side of the two pole one. 

Connect the incoming hot to the center of the center terminal of the 3 pole switch. Connect P1 from the motor to both the upper center terminal and the lower center terminal of the switch. 

This will cause the incoming hot to be disconnected from the motor when the switch is in the center position.


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