# wiring 1/2hp single phase from 220 to 110



## archer292 (Jan 13, 2015)

I have a 1976 south bend 10k I purchased from a school and it is wired for 220. It also has an electric control box on the rear containing ( what looks like)  two  switches and a push button fwd/rev/stop on the front of the cabinet. I would like to run the leeson 1/2 hp single phase motor 110v and still be able to use the push button switch.  The motor has 6 leads, T1,T2,T3,T4,T5,and T8. I was hoping it would be a quick wiring rearrangement but I'm not so sure. The front push button switch wires are marked with the T1,T2, etc designation also. I will include a pic of the box and motor. Any help would be appreciated and will gladly supply any other info needed.


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## Terrywerm (Jan 13, 2015)

Not my area of expertise, but there are other members that will probably be able to answer your questions once they see this thread.  Be patient and the answer should come.


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## Ulma Doctor (Jan 13, 2015)

I'm not seeing a step down transformer to provide control voltage.
 it's very likely that the contactor coils require 220 volts for operation.
you would either need to replace the contactor coils or the contactors themselves in order to facilitate 110 volt operation, if i am correct.

ebay has tons of 110v contactors, you will need 2 , one for forward operation, one for reverse.
that is unless you are lucky enough to find a deal on a reversing contactor
(which incidentally is just 2 contactors wired together. the second contactor that has 2 input leads reversed which reverses motor direction, just like you presently have)

the change over should be pretty straightforward .
you'll be using the motor wiring diagram on the left side of the name plate for low voltage operation.
you will need to make provision for reversing motor leads T5 and T8 to facilitate opposite rotation of the motor.
you can retain the push button switches if you desire.

or
another way of wiring the 110v motor would be by the use of a 15 or 20 amp- 2 pole reversing switch which are also abundant on ebay.

should you have problems finding either item,
i could get you some from my shop stock for a nominal cost+ shipping.
i'm not looking to make any money just parts costs.
send me a message if you are interested

mike)


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## Ulma Doctor (Jan 14, 2015)

Here's a childlike(on my part) drawing scan.
the drawing is oversimplified, the control circuit has been omitted for ease of  viewing the current path
i whipped it up(hastily) to better explain how the motor will be wired up as it is in operation for each direction.

maybe it may shed some light as to what happens in regards to motor wiring as you change direction.
you'll be accomplishing the very same thing with the use of electrical contactors and control circuit.
a look at the crude sketch for the interested....





i did make a mistake in the scan, CW and CCW should be reversed, i have them mislabeled.


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## cathead (Jan 14, 2015)

*Look at the control box for clues....*

It says polyphase on the controls if you look carefully at it.  Consequently, the
controls may be for a 3 phase motor.  If this is so, then you will have to replace
all the controls with a double pole double throw drum switch or similar to have
forward and reverse on the Leeson.  Is that the motor for that lathe?

Also the 3 wires on the bottom right of the control box look clipped off and would
be indicative of a 3 phase setup.   Also notice the terminals say T1, T2, &T3 which
leads me to believe it is a 3 phase setup.


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## Ulma Doctor (Jan 14, 2015)

*Re: Look at the control box for clues....*



cathead said:


> It says polyphase on the controls if you look carefully at it.  Consequently, the
> controls may be for a 3 phase motor.  If this is so, then you will have to replace
> all the controls with a double pole double throw drum switch or similar to have
> forward and reverse on the Leeson.  Is that the motor for that lathe?
> ...




Hi Cathead,
sorry, i disagree as far as control replacement- there are a million ways to skin a cat (no pun intended)

the existing contactors are 3 phase contactors- on that i do agree

I can't say it never existed- but, I haven't ever seen a 3 phase dual voltage motor that will operate on single phase 110v.

this Leeson is a single phase- dual voltage motor

the only difference between 3 phase contactors and single phase contactors is the addition of a 3rd pole for the 3 phase contactor. 
there is no other difference!!!!

If you look at the incoming power wiring, there are 2 conductors and a ground- indicative of single phase supply.

there is no magic, dependent on how the contactor is wired,  will switch one pole or all 3 at the same time.
a 3 phase contactor can be safely used on single phase circuits, provided it's rated for the intended work.
conversely, in most instances single phase contactors shouldn't be used in 3 phase circuits because it will only break 2 poles.
no other difference.

for 110 volt operation, i use 110volt/20amp rated components whenever possible, for longevity.

there is a few ways the lathe could be wired up. 

it will not be necessary to ditch the existent control system, quite the contrary...
all of the components, less the contactors or contactor coils, can be utilized to provide directional control.

were not really dealing with rocket science, just a low voltage single phase change over.
surprisingly, it will wire up just like it's wired for single phase 220v with the exception of the motor tap wiring.
if the contactor coils are replaced or replace the contactors themselves, this will be a slam dunk!!!


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## archer292 (Jan 14, 2015)

Although I did not see the lathe run, it was totally together when I picked it up. Nothing looked as though it had been separated for sometime. I clipped those wires to remove the motor and under drive as one unit. The motor has the wires attached as they were. I left the pig tails on those leads so I would know what went where. I am trying to get a grasp so bear with me please. My original thought was that I would  change the  wires on the motor to 110v then wire them to the leads in the box and then get a standard 110v plug and wire, and wire that to the box for incoming power.  What I think I am understanding now is that part of what's in the box will not work with 110v power, the contactors or contactor coils.


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## jim18655 (Jan 14, 2015)

The motor needs at least 4 wires between the contactor and the motor to change direction. The start winding phase relationship to the run winding determines direction. It looks like the 4th wire was the white wire on the 'C' phase on the top of the right hand contactor. Is there a reason not to keep it on 220v? As someone said the coils will probably need to be changed. Leave it 220v and you'll have the built-in overload protection.


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## Ulma Doctor (Jan 14, 2015)

archer292 said:


> What I think I am understanding now is that part of what's in the box will not work with 110v power, the contactors or contactor coils.



Hi Archer,
you are correct,
unless there is a stepdown transformer somewhere, it is most likely that the old system has 220v coils in the contactors.
you can't get proper operation from 110v.

you can wire it up with a simple reversing 20 amp 2 pole(DPDT 20A -on/off/on) toggle switch too rather than using contactors, if you want.
it's pretty cheap and for 1/2 hp it would be simple to wire in and easy to troubleshoot if you should ever have a fault.


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## LEEQ (Jan 14, 2015)

If the breaker box is anywhere nearby, pulling a 220v wire and adding a breaker seems simple. You would also have your machine on it's own circuit. It is very interesting to learn the crazy things you can do with power and components, and I study all the threads remotely like this, but at the end of the day I do like a solution elegant in it's simplicity. I also have little electrical background beyond household single phase. UlmaDoctor has been kind enough to help me decipher motors and such. You are in good hands, good luck


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## archer292 (Jan 14, 2015)

I have no free breakers in my box to run a 220 line. The lathe is not 10ft from the box.


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## LEEQ (Jan 15, 2015)

I ran into the same thing. I ran a small sub panel. I am mindful of how much I'm pulling and don't try to run everything at once. I think I could, but no sense pushing it. I have never found anything to be warm or tripped breakers or anything, so I'm very happy with the set up. If you are lacking just space, not more service amps, it might be an option for you also. Hopefully somebody can clarify what I'm driving at.


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## Wireaddict (Jan 23, 2015)

I've added quite a few sub panels to permit more circuits also.  I believe I'd stay with the reversing starter you have in the panel but I'd look for a Westinghouse/Wesco distributor to get 120VAC coils for it & [3] overload heaters for 8.8A & also make sure that the contacts for that starter will handle 1.25% more than that or 11A.  A good thing about reversing starters is that they have both electrical & mechanical interlocking to prevent forward & reverse contactor armatures from picking up at the same time.  Since you'll be using 120VAC the neutral wiring to motor leads T2 & T4 won't need to be switched so connect these leads to L3 on the top of the starter [the white wire].  Connect motor leads T1 & T3 to starter terminal T1; motor lead T5 to starter terminal T2 & T8 to starter terminal T3.  This will reversing the phasing of the motor start winding current in relation to the run winding current & minimize extra winding.  And if the motor runs backwards in relation to "forward" & "reverse", simply switch motor leads T5 & T8.


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## Eddyde (Jan 23, 2015)

I would go the drum switch route, simpler to hook up and easier to use.


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## cathead (Jan 24, 2015)

Me too.


QUOTE=Eddyde;268068]I would go the drum switch route, simpler to hook up and easier to use.[/QUOTE]


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