View Full Version : Wiring For Logan Lathe

06-22-2011, 01:00 PM
I just bought a Logan model #922 lathe. It is 110v but I am not sure how to wire it up (electrical is not my strong point!). There are wires (in flexible conduit) coming from both the motor and the forward/reverse switch, going into either side of a junction box that the previous owner must have had mounted to the wall. Then the wires come out of the junction box which I assume I need to connect to a 110v supply.

Wiring. There are 5 five wires that go directly from the motor to the switch linking them together these are brown, red, yellow, orange and light blue I shouldn't need to touch these. Then coming from the motor to junction box is a dark blue and a white wire which are not attached to anything at the junction box Coming from the switch to the junction box is a black wire which is not attached to anything at the junction box.

I hope I have worded this so it is understandable, I desperately need help!

J Tiers
06-22-2011, 09:50 PM
Unfortunately that is not enough information for specific instructions in your case...... And instructions for non-electrical folks over the internet is less than safe and productive.....


A 110 motor has 2 windings (three if it is 110/220). One is connected whenever the motor is running, and one goes through an internal switch, and is used for starting only. Each need 2 wires that connect to 110VAC.

The start winding is automatically switched out, and you should not need to do anything but hook it up, the motor takes care of switching it off.

If these wires are labeled 1 thru 4, with 1 and 2 being the "run" winding, and 3 and 4 being the "start" winding, then.....

if 1 and 3 are connected, and 2 and 4 are also, the motor will start and turn one direction, maybe clockwise, when power is hooked with (for instance) hot on the 1,2 group, and neutral on the 3,4 group.

if instead, 1 and 4, and 2 and 3 are connected, it will start the other direction.

The usual wiring sends power through one switch, and uses a second to reverse the start winding versus the run winding, as per above.

it can also be done with a single more complex switch (known as a "drum" switch).

If you look carefully at what you have, you may find that it is done that way in your case. probably you should find an electrically savvy person to look at what you have, in order to ensure that it is as expected, and constructed safely.

I have had to re-wire every machine I have bought, due to well-meaning but less-than-competent folks doing the wiring. There are exceptions, but it seems they are few and far between. It is impossible to comment further without seeing the setup, and being able to trace wires, etc.

Al Messer
06-22-2011, 10:04 PM
Ask Scott Logan on the Logan Lathe Users Group. He can probably send you a wiring diagram for it.


Gary Paine
06-22-2011, 10:22 PM
I understand you are in need of assistance, but without more information, it is risky business to try to help.
There are more than one possibility for what you are looking at, and the wire colors are not to be relied on, so let me explain what I hope is enough to get you going.
Your motor should have a wiring diagram on it that will help immensely. Many small motors will have two terminals to hook to incoming power. The plate will say something like “to reverse rotation, reverse leads A and B referring to two different terminals in the motor. In Mr. Tiers’ example, that would be leads 4 and 3.
To accomplish reversal of the leads on the two terminals, each terminal needs to be brought up to the switch box and the wires that hook to them need to be brought to the switch box. That will account for four of the leads. The 5th wire (light blue?) will probably be switched power to the motor and is being switched separately in the switch box.
The black single lead from the junction box to the switch will likely be the input power to the switch.
The dark blue and the white wires in the junction box that go to the motor are possibly the second power lead and the ground, but I am uncomfortable thinking that the ground would be dark blue…:confused: ?
When I do a small motor hook up, I like to use a good 16 gauge extension cord and cut off the female end. That gives me a sturdy molded in polarized plug already wired. When you look at the wires inside, there will be a black, white, and a green one. The black is the hot one and is the one that should be switched. The white should be neutral and will be connected to ground inside your main electrical service box. The green should be ground and for safety should be hooked up to the case of your motor and/or your lathe.
Open the case on your reversing switch and your motor plate and confirm your understanding of the wiring.
If you do not have an ohmmeter or a continuity tester, I suggest at least rigging one up using batteries and bulb from a flashlight. Trace the wiring to confirm you understand what is being hooked where before plugging anything in.

06-24-2011, 12:48 PM
Thanks for the replies and info. I have looked a little closer and it appears that the motor on the lathe has been replaced at some time or another. The motor on my lathe is a 3/4hp 115/230v Dayton capacitor motor. In the Logan manual there are only options for 1/2hp 115/230v plus 3phase options.

I think I am going to try to find someone locally that can wire it for me. I have a 230v outlet that I use for my welder so maybe I can use that for the lathe also. what is the advantage (if any) to using 230v?

Thanks again,

06-24-2011, 07:33 PM
I was about to send you pics of my #912 until I read your last post. My wiring will do you little good if you're not working with the original. I took the pics in case I ever wanted to go back to an A/C motor. Currently running a 3hp DC out of a treadmill, and I can't imagine ever going back to fixed speeds. Once you experience the freedom of a variable motor, it's hard to turn back.

06-24-2011, 09:21 PM
Post a Picture of the motor junction box and one of it's wiring diagram. Might want to post your location also so in case one of us are your neighbors so we can swing by and give you a hand which many of us are happy to do.

Gary Paine
06-25-2011, 10:03 AM
The dual voltage motor when properly wired will be fine on either voltage, but there is a good reason to use 220 if possible. When a 110/220 motor is run on 110 volts, the current drawn by the motor will be twice as large as the current at 220 volts (power = voltage x current). The wiring supplying the current to the machine will have a resistance that is a function of wire gage and length of the circuit. The resistance x current = voltage drop across the wire. For a given wire gage, this voltage drop (loss) would be half as much for the same length of run with 220 volts as it would be at 110 volts. Unless you have a dedicated 110 volt line for the machine, you also have to consider other lighting and equipment on the same circuit and make sure you are not exceeding the current carrying capability of the circuit. Your motor probably consumes about half of that circuit capability all by itself.
An example of the problem is trying to run a 2 horsepower air compressor on 110 volts through a typical extension cord. Probability is that it will not start, but will only hum. Because of the high current, the loss in the extension cord is sufficient to steal enough of the voltage from the motor that its efficiency is very low and it will just overheat and burn up. The extension cord will heat up too. The same unit plugged into an outlet (no extension cord) will run fine. Had that been a 220 volt extension cord, it would have probably worked fine.

07-01-2011, 02:34 PM
Thanks guys, I have been on vacation so still don't have the wiring done yet! I did take another look at the supply wires coming from the junction box that I mentioned in the original post. The dark blue wire is just conected to the motor housing so I am assuming it's the ground wire and that just leaves the black and white wires. I can see the wiring diagram on the outside of the motor but when I removed the cover on the motor I can only see wires coming from inside the motor and nothing relating to the numbered plate (wiring diagram) on the outside.

I may have just confused you all even more... sorry! I am located in Redlands SoCal so if any one is local and can help me or knows someone I can get to help I would appreciate it.