Trying to find out if this wiring will work for Smith and Jones 2HP (Harbor freight Motor) Wanting to run it on 220 volts with drum switch, Single phase. I am restoring an older engine lathe and had to replace the switch and motor, I need this to be able to run forward and reverse. Rotary switch positions and wiring from inside of motor cover is on the drawing. I Would like to wire it correctly and be able to share the results on the net. I have found a few other wiring drawings that were not correct and want to be sure.

 

There is no clearly labeled diagram for the Switch Connections when it is in the "Off" position.
Are any of the Switch Terminals connected to each other when in the "Off" position ?
This must be verified with an Ohm-Meter first.

Drum-Style Switches are not guaranteed to meet any particular Standard or Terminal-Layout.

Never rely on the Color-Coding of the Motor-Wires in a generic Wiring-Diagram,
they may be different between different manufacturers, or may even be all-Black.
Do not include the actual Motor Wire Colors in your Drawing,
use the numbers/letters only,
otherwise someone may have a different Motor, and
assume that the Colors are always Standardized, and smoke something.

Motor Wire Colors are NOT guaranteed to meet any particular Standard.

There is an extra, unlabeled-Wire, in the Motor-Cover Diagram
between T-4, T-5, and L-2, in the CCW Wiring that may cause confusion.

Otherwise your diagram looks correct.

 

I will check the off position of the switch, and put that on the drawing also.
Thank you for your help. This one has been a stinker for me for some reason

 

After checking switch in the off position there are connections being made, only when in either forward and reverse. I will update drawing to show this

 

Looks like T5 and T8 are the reverse windings, the switch wiring looks correct to me,.

 

There is no clearly labeled diagram for the Switch Connections when it is in the "Off" position.
Are any of the Switch Terminals connected to each other when in the "Off" position ?
This must be verified with an Ohm-Meter first.

Drum-Style Switches are not guaranteed to meet any particular Standard or Terminal-Layout.

Never rely on the Color-Coding of the Motor-Wires in a generic Wiring-Diagram,
they may be different between different manufacturers, or may even be all-Black.
Do not include the actual Motor Wire Colors in your Drawing,
use the numbers/letters only,
otherwise someone may have a different Motor, and
assume that the Colors are always Standardized, and smoke something.

Motor Wire Colors are NOT guaranteed to meet any particular Standard.

There is an extra, unlabeled-Wire, in the Motor-Cover Diagram
between T-4, T-5, and L-2, in the CCW Wiring that may cause confusion.

Otherwise your diagram looks correct.
.
.
.

I made a new PDF version of drawing hope this is closer to being correct
Thank you again for your help

 

The P2 wire is probably for a different voltage source. Tape it up securely.

 

I'm going to disagree with what has been said so far. Never saw a drum switch used for 230/240V that didn't have both of the live wires NOT in the switch. Wiring the switch without both lives/hots controlled by the switch is just plain wrong. Doing it like that leaves one of the hots connected even when the switch is off.

While this Youtube shows the guy wiring for 120V his explanation still stands, how he explains how to interrupt the switch and it's wires in the motor, just change it for the higher voltage diagram.

 

It can work with the one side unswitched, does that drum switch have additional contacts?OR add a cam to allow another switch to oprn the P1 connection in the off position.. OR get an extension for the drum switch.

 

Disconnecting both Hot Wires in the "Off" position
could be a bit safer under certain circumstances,
but it is not required by the NEC (National-Electrical-Code) in the USA.

What IS required is either a "Plug-and-Socket" or a
dedicated, Hard-Wired, "Safety-Disconnect",
mounted within (a certain number of feet) or in-sight of, the protected device.

All Residential Air-Conditioning units switch only one Phase-Leg.

 

I added a little more info on the drawing showing all the positions of the switch, and numbered the wires with respect to the switch terminals. And I wanted to show a disconnect switch if someone wants to use one. I am just trying to make a solid and trustworthy drawing to share. Seems like a lot of people have the same question, any info to make this a better drawing is appreciated.
Thank you all for your help

 

All Residential Air-Conditioning units switch only one Phase-Leg.
.

Air conditioners also aren't reversing the direction of rotation.

Not picking on you, but mrbill doesn't understand motors, so directing my answers to you. If you look at the very weird way the wiring diagram is made for this motor compared to the usual way of just saying, "to reverse rotation switch X and Y wires." The guy in the Youtube video I posted interprets it right. Both hot wires NEED to run through the drum switch. They need to because that is the only way wire "X" and wire "Y" can be reversed to the motor and those wires are both the hot lines from the mains.

I used "X" and "Y" because I'm not going to take the time to change the PDF orientation to get the real designation from it.

 

I think this motor is a dual voltage (110 / 220 volts ) motor which may be causing some confusion. The main winding is split into two sections. (I will call them main 1 and main 2) The way it is shown is strapped for 220 volts. The two half's of the main winding are connected in series so each one has 110 volts across it. For use on 110 volts they would be connected in parallel. To simplify the design the start winding is 110 volts which is just connected in parallel with the two main winding for 110 volts. When used on 220 volts the two main winding in series act as an auto transformer so connecting the start winding in parallel with ONE of the two main winding supplies it with 110 volts.
This is how I think it is wired.
T5 and T8 connect to T3 and T4 via the reversing switch. I have shown a start capacitor and centrifugal switch in series with the start winding but these may not be used on this motor. The way the drum switch is show wired also breaks the L2 feed to the motor. (But this leaves the motor still connected to L1 in the middle off position. This is why a double pole switch should also be fitted.

Les.

 

Air conditioners also aren't reversing the direction of rotation.

Not picking on you, but mrbill doesn't understand motors, so directing my answers to you. If you look at the very weird way the wiring diagram is made for this motor compared to the usual way of just saying, "to reverse rotation switch X and Y wires." The guy in the Youtube video I posted interprets it right. Both hot wires NEED to run through the drum switch. They need to because that is the only way wire "X" and wire "Y" can be reversed to the motor and those wires are both the hot lines from the mains.

I used "X" and "Y" because I'm not going to take the time to change the PDF orientation to get the real designation from it.

I do understand motors, SB, but in every application I have done that had a motor they always were controlled by a motor starter that broke all three phases. And for the reversing applications there were two starters , interlocked in some manner, so as to prevent crossing phases.
Certainly just swappingT5 and T8 with the drum switch will work, it sems that I was not payinh adequate attention. That may happen on occasion, I am not infallible any more.

 

I must be getting dense ......
I don't understand where all the extra verbiage is coming from.
With the illustrated Motor and Switch, it's not possible to switch both Hots,
and there is very little, if anything, to be gained by doing so.
There are no exposed wires,
the Motor-Case is Grounded,
and the NEC doesn't think it's necessary,
as long as there is an approved "Means-of-Disconnect".

So it's all good as far as I can see.

If this Motor was something you could stick your fingers into,
that might be a different story.

If anyone is concerned about additional safety, just power it with a GFI Circuit-Breaker,
they are standard equipment for Pool and Spa installations.

 

While not using a drum switch I just replaced a motor like this on one of my belt grinders. From the factory it turned in the wrong direction so had to reverse it. And since the wiring diagram is so different than what I've seen before I had to study to understand it but got it reversed. But I also use a contactor on mine with a 120V coil control. You guys just keep on breaking one side of a 240V motor switch if you like, it will bite you or someone else down the road.

And I had to look, my air conditioner uses a contactor that breaks both hots on the 240V side.

 

I think this motor is a dual voltage (110 / 220 volts ) motor

Hi Les, it is a two voltage motor, cap start, cap run. The problem isn't the change of voltage, but making it reverse with a drum switch.

 

When I had to do some service on my AC compressor I was deeply offended to discover that only one side is switched. There is an actual benefit to double-break switching in that the arc length is twice as long. AND, if there is ever a lightning spike on the line, the compressor is more isolated. Since I have suffered two direct hits near the AC compressor that IS a big deal for me. Now I do need to change the contactor.

 

Yeah, but, but,
the Manufacturer saved "0.03268" Cents per Unit.
I thought it was a pretty cheezy practice too.
I think it started to become a trend back in the late '80's.
You'll find the same practice employed on the Air-Handler-Blower-Motor,
but it's not as susceptible to Lightning.

 

Hi SB, I don't see any problem with reversing the motor using the drum switch. The circuit in post #1 should work.

Les.