# Repulsion-Induction Motor / Drum Switch Wiring Woe...



## Eddyde (Nov 25, 2017)

Hi All,

I scored a somewhat historical lathe, a couple of weeks ago. For the most part it is in great shape and only needs a little cleaning, lubrication and new belts. However, in the process of moving it, I had cut the wires to/from the motor and drum switch, I didn't id the wires as I should have (duh) since I thought it would be no biggie to figure out as the motor has a wiring schematic on the spec plate and I have wired several drum switches in the past... I also wanted to replace as much of the old wiring as possible, anyway. 
Upon rewiring I have some uncertainties: First, I have no experience with Repulsion-Induction Motors hence, the diagrams on the motor plate are a little unclear to me, as to how it should be wired. Of the 2 diagrams, initially I thought one showed forward status and the other showed reverse, but the diagrams also show different interconnections on the motor, leading me to think the one on the left is for low voltage and the one on the right is for high voltage hook up, although no voltage or amps are stamped on that side of the plate. Further confusion as there are only 4 wires exposed in the motors junction box so none of those interconnects could be readily made, anyway. So I think, the left digram is the one I should follow, but I am somewhat confused buy the "X" pole representing the drum switch. I assume the status shown is "forward" but how would it look in reverse?
So far, I have searched the net and come up with little. One photo of an old paper schematic looks like it is the correct one but is torn and missing the half the circuit (as is always my luck). 
I have determined T1 & T2 have continuity as does T3 & T4.
I have determined the switch pole configuration.
I hope someone here can assure me of the correct wiring?










Many Thanks in advance.

Eddy


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## markba633csi (Nov 25, 2017)

Hi Ed, I can help: You are correct the left and right diagrams are for low and high voltage, respectively.  This motor may be only for 110 volt if there is no other terminal board deeper inside the case.
The "X" picture is the drum switch but the two swinging contacts or poles are not shown- you have to imagine the two poles of the switch swinging left or right for forward and reverse. I can do a sketch to clarify if you need one. Does the drum switch have a center off detent? If so you would run one line wire through the bottom contact for center off.
Mark
ps that's some really vintage stuff you've got there!


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## markba633csi (Nov 25, 2017)

Important point: I don't believe the switch symbol shown on the motor directly translates to the pins on your drum switch- 
I'll sketch it up and post it here- stay tuned
Mark


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## Eddyde (Nov 25, 2017)

markba633csi said:


> Hi Ed, I can help: You are correct the left and right diagrams are for low and high voltage, respectively.  This motor may be only for 110 volt if there is no other terminal board deeper inside the case.
> The "X" picture is the drum switch but the two swinging contacts or poles are not shown- you have to imagine the two poles of the switch swinging left or right for forward and reverse. I can do a sketch to clarify if you need one. Does the drum switch have a center off detent? If so you would run one line wire through the bottom contact for center off.
> Mark
> ps that's some really vintage stuff you've got there!


Thanks Mark,
Yes the drum switch is center off. 
I did a bit more research and it seems the Repulsion-Induction Motor has two windings in the stator, a start and a run. the rotor is energized by inductance but its windings are connected to itself by brushes which disengage when it come up to speed. I had never heard of this arrangement before. Another thing I noticed, the amps are 7.2 and voltage is 110 so 792 watts, I think that is slightly over 1 hp. yet the motor is rated at only ¼ hp.? Guess either they severely underrated the motor or that design is very inefficient... 
A drawing would be great, if its not too much trouble.
Many Thanks
Eddy


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## Blackjackjacques (Nov 25, 2017)

RI motors are antique and were used before the use of capacitors.  They are wound rotor devices using brushes for startup that are shorted with a centrifugal arrangement once the motor reaches speed.  These motors have great startup torque and reach speed quickly - therefore, the brushes seem to last forever.


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## markba633csi (Nov 25, 2017)

That would be 1 HP at 100% efficiency but they never are.  
Could you post a closer pic of the drum switch- same top view but closer? Thanks
Mark


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## Eddyde (Nov 25, 2017)

markba633csi said:


> That would be 1 HP at 100% efficiency but they never are.
> Could you post a closer pic of the drum switch- same top view but closer? Thanks
> Mark


Here ya go. 


Off


Forward


Reverse



The whole thing is one casting!


Please let me know if you need any more.
Thanks
Eddy


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## markba633csi (Nov 25, 2017)

OK very good give me a few minutes-  
Mark
ps I think you could bump-start Frankenstein with that switch


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## markba633csi (Nov 25, 2017)

Here are two ways you could wire it Ed,  "A" is the simplest and does not break the neutral line when off.  "B" breaks both line wires when off.
You'll notice the Run and Start windings are interchangeable- swapping the ends of either one with respect to the other reverses the motor.
Mark S.
	

		
			
		

		
	



I suspect it was wired like "B" before you cut it.  If the motor was dual voltage you would want to use the "B" connection too for 220v.


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## benmychree (Nov 25, 2017)

I beg to differ with most who posted on this; I am familiar with repulsion induction motors, and the only  thing that can be done by connecting the motor wires is voltage, either 110 or 220 volts; to reverse these motors, the brush holders are shifted, there should be an access plate on the back end of the motor that exposes the brush holder and there would be a pointer and two marks, for CW and CCW rotation.


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## Eddyde (Nov 25, 2017)

markba633csi said:


> Here are two ways you could wire it Ed,  "A" is the simplest and does not break the neutral line when off.  "B" breaks both line wires when off.
> You'll notice the Run and Start windings are interchangeable- swapping the ends of either one with respect to the other reverses the motor.
> Mark S.
> 
> ...


Many Thanks Mark, That is very helpful. I was doing some more digging around the net and found the windings need to be in series, so your schematic makes sense. I'll try it... If I never post again, please be sure to revise it, LOL.


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## markba633csi (Nov 25, 2017)

Be careful, and don't forget to provide a good ground wire to the motor.  Remember your motor was made for 110 volts only as far as I can tell.
Mark


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## JPigg55 (Nov 25, 2017)

Am I missing something  ???
When I look at the motor label plate, it appears to me to be a 1/4 HP reversible motor, but I only see stamped data for 110 volts. The blocks for the high voltage side are blank.
I know many of these data/wiring plates are generic and just stamped for the specific model. Although admittedly , I don't know much about repulsion induction motors.


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## JPigg55 (Nov 25, 2017)

I did a quick Google search on repulsion induction motors. Rather interesting.
Hard to tell from the pictures of the motor to see if it's like the one in this video.


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## markba633csi (Nov 25, 2017)

I mentioned this earlier(post #2), unless there is another terminal block inside then the motor is dedicated for 110 as far as I/we can tell-
I've never seen a dual voltage motor that didn't say so on the nameplate somewhere, so I'm assuming this is an economy model that was factory set
for just the one voltage.  
Mark


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## Eddyde (Nov 25, 2017)

I ran all the new wires, ready for final hookup but its getting late and I'm getting fuzzy... will have to wait till tomorrow.


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## Eddyde (Nov 26, 2017)

It's Alive! 
At first, the motor ran backwards relative to the switch position but I simply switched the connections on 3 & 2 and it is now, rotationally correct.
Motor runs smooth... Next up, splice the flat belt in and start making chips!


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## markba633csi (Nov 26, 2017)

Good deal Ed- that's a super nice lathe especially with all the history attached- I'm jealous as H**L  
Mark
ps by the way if you ever take the other covers off the motor I'd be curious if there's any other terminals in there- If you could run it on 220 your vintage drum switch would last longer and the motor runs cooler too.


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## markba633csi (Nov 26, 2017)

Ed: Does the motor go instantly from forward to reverse or does it have to come to a stop first?
Mark


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## Eddyde (Nov 27, 2017)

Mark Thanks again for all your help, it is much appreciated.


markba633csi said:


> Good deal Ed- that's a super nice lathe especially with all the history attached- I'm jealous as H**L
> Mark
> ps by the way if you ever take the other covers off the motor I'd be curious if there's any other terminals in there- If you could run it on 220 your vintage drum switch would last longer and the motor runs cooler too.


I'm fine with it at 110v, I have it temporarily on a lighting circuit and they barely dim when it's switched on. However, I am curious to see the brush arrangement, it appears there are easily removed covers at the ends of the motor. I'll have a look when I have time.


markba633csi said:


> Ed: Does the motor go instantly from forward to reverse or does it have to come to a stop first?
> Mark


Yes it seems to have quick reversal, not as fast a servo but fast enough. I'll check that out more the next time I'm at my shop, in a few days.


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## Eddyde (Nov 27, 2017)

Just wanted to show the new wiring installed for anyone following...


Drum Switch with crimp terminals and markers.


The old cloth/rubber insulation on motor leads were fraying so I coated them with "liquid electrical tape".


Crimp on eyelets screwed to the lugs, as per original connections.


Even used some old school friction tape for the outer layer.



All motor, switch and line inter connections are made in the junction box.


I had to make a cover for the junction box, it was a small victory for my scrap bin as the piece of stainless was the perfect size, no cutting needed, I also remember my helper rolling his eyes when I told him to save it... Ha!


The motor leads as attached to the switch terminals.


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## markba633csi (Nov 27, 2017)

Very nice job, bravo!  It should be noted, by others reading this, that the reversing action of motors of this type differs from the more modern
capacitor-start types and could actually cause a chuck to come loose very suddenly if care is not taken.  Ciao.
Mark


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## Tim9 (Nov 30, 2017)

benmychree said:


> I beg to differ with most who posted on this; I am familiar with repulsion induction motors, and the only  thing that can be done by connecting the motor wires is voltage, either 110 or 220 volts; to reverse these motors, the brush holders are shifted, there should be an access plate on the back end of the motor that exposes the brush holder and there would be a pointer and two marks, for CW and CCW rotation.


That is what I thought also. I was reading this post and was a bit bewildered because I have run across 2 repulsion motors in the past and it was not an easy thing to reverse the rotation. It can be done and on the easier ones there is a lever which is switched. On the other I had, I had to rewire internal wiring and it was a bit of a pain.
  In any case, I'm glad you got yours working good for you.


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## markba633csi (Nov 30, 2017)

This must be an unusual type that isn't too common, fortunately for Ed
Mark


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## Tim9 (Dec 1, 2017)

markba633csi said:


> This must be an unusual type that isn't too common, fortunately for Ed
> Mark


Maybe. FWIW...This is the older article I referenced when I was playing around with my Repulsion Motors trying to figure out how to reverse them. http://www.practicalmachinist.com/v...on-induction-motor-reversing-rotation-260711/

Pretty good article with lots of pics and references. In any case, like the old saying goes....I learn something new every day. And as far as that goes...I tend to learn something new whenever I have to work on an electrical motor. An expert I am not.


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