Wiring/Switch Question for 9A motor...little HLEP please!

So 250 views on my other thread where the title wasn't as specific, so I'll try again...
Kingston Conley single phase, 110v, 1/2 hp, 1740 rpm. It's model name is "SB" so it may be original, or a specifically designed replacement. Seems to date from the 49-50 period of the lathe.

Inside the wiring compartment for the motor, is a simple plastic terminal block with two studs for the two motor wires, and corresponding hot and neutral feeds (I have had to add a ground to the motor case as there was no provision for one).

When I got the lathe, it had a simple on-off wall switch mounted on the gear guard.

Is this all the motor is capable of? If so, no point in getting a fwd/rev drum switch, right?

Appreciate any help. I'd like to get this running.

From the picture, it appears that it MIGHT be the original motor but no guarantee. In order for you to be able to reverse that motor, you need to have at least 4 leads coming into the terminal box from inside the motor. There could be more wires if it's a 115/230 motor. There could be 4 leads from the main winding if it's 115/230 volt or just two leads if it's 115 volt only. Then there should be two more leads from the starting winding. Your task as the operator would be to provide power to the main winding and to the start winding. Depending on how you hook the start winding to the main winding terminals, it will run either clockwise or counter clockwise. To reverse the motor, you leave the main winding alone and hook up the start winding with the leads reversed.

The job of the Cutler Hammer rotary switch or Furnas Electric (typical--there are other brands) drum switch is to provide you a means of changing how the start winding is hooked up without changing the main winding. If you look at one of those switches, you will be able to see how that's accomplished.

Typically, you would have your supply cord coming to the switch and then two wires would go to the motor: One is for the main winding and the other cord is for the start winding.

If that's the motor that came with the lathe then if almost certainly would be capable of being reversed since a lathe without reverse has limited utility for a lot of operations. You could certainly use the lathe without reverse but you'd be missing half the fun. For example, cutting threads without a threading dial requires that you reverse the lathe to move the tool point back to the start of the thread.

You might as well ante up and get a reversing switch because even if that motor can't be reversed, you'll certainly want to get one that can. And if you want to go deluxe and use a 3 phase motor with a VFD controller then you can use the same reversing switch to control the direction of rotation though the VFD.

I'm confoozed....
If only two wires would go to the motor, then why would the motor have more than two (hot and neutral) inside?
IOW, if I'm understanding you correctly, and as I alluded to in my other post- if the switching between the start and run wires is done inside the drum switch- why would the motor need more wires inside to be hooked up?

So...you're saying the motor might be reversible (and if it's the original, should be)- depends on the internals- go ahead and get the drum switch and find out?

The guys that can help will want a pic of your data plate and a pic of the wiring with the cover off.

In order to reverse a single phase motor, you must flip the wires on either the run winding, or the start winding, but not both. Hence, you need 4 wires at a minimum. If you look on the back of the terminal block, you might see 4 wires connected there. You could split them from the block, and wire them separately. You can use a resistance meter to distinguish between the two windings. The run winding will be lower resistance. The start winding will start out with a very low resistance that climbs as the cap fills.

allan

Alan is correct except that I have seen single phase motors where there is no practical access to the start windings. They are wired into the main windings deep inside the motor and to gain access to them you'd have to start undoing internal connections within the winding coils. I certainly wouldn't attempt it and I have rewound motors by hand previously. In fact, I have a really nice 1 HP Century capacitor start motor which does not provide an option for rotation direction and I won't cut into the windings to fix that. I wanted to use it on my table saw but it goes the wrong way.

The reason I said to go ahead and get the switch is that you're going to need it eventually anyway so why limit yourself to a single direction lathe? If the motor you have can't be reversed, then you should get one that can.

A couple of photos would help a lot!

Pictures are very important here as is any information on the data plate. Many motors have wires coming out
of the windings that don't come out to the terminal block and can't be seen easily with just the terminal box
cover removed. The end bell may have to come off to reveal them and that's a pain 'cause of the centrifugal
switch assy for the start winding. I've not seen a newer motor that didn't have all the leads accessible but I
have seen older ones where the additional wires were inside the end bell.

Pete

If you end up wanting to replace the motor with one that is known to be reversible, a 1/4 hp will do fine on most typical 9 inch SB. The exception would be if you're gonna run the spindle much above 1000 RPM or if you're taking huge hogging cuts. My reason for sticking in my two cents is that you can usually find a decent 1/4 hp or 1/3 hp, with easy reversing, for under $20.

kitno455 said:

In order to reverse a single phase motor, you must flip the wires on either the run winding, or the start winding, but not both. Hence, you need 4 wires at a minimum. If you look on the back of the terminal block, you might see 4 wires connected there. You could split them from the block, and wire them separately. You can use a resistance meter to distinguish between the two windings. The run winding will be lower resistance. The start winding will start out with a very low resistance that climbs as the cap fills.

allan

Click to expand...

Wow- had you not said that, I never would have looked there- because of the angle coming into the back of the terminal strip, I never even noticed them!

There is one wire, on the back of each stud. I thought they were just blind studs molded into the plastic strip!



OK, so four wires (with that crappy old "insulation" that I need to be very delicate with)- now what?

I assume I need to bring the other two wires out where they're accessible, prior owner must have buried them when he went to an on-off switch (why the he** would anyone do that with a reversing motor?)

Will this Dayton switch work- and anyone know if it comes with a wiring diagram that's straightforward?

DAYTON 2X440 Switch,Drum Reversing

(I'm really not stupid or dyslexic- I was just in a hurry when I typed "HLEP" in the thread title!)

Your Dayton drum switch should work just fine. Look inside the cover of the switch for wiring diagram(s).

If you are determined to save this motor, I would take the end bell off, and inspect/replace the lead wires. Spend some time with a resistance meter and identify the coils. Once you get a switch, we can help you wire it.

allan

Thanks- motor being disassembled and cleaned. I've NEVER seen so much crap inside a motor before.
Degreasing what parts I can, going to blow everything else out with compressed air, clean out and oil bearings.

Pics to follow, showing the four wires. One of them, terminates in some sort of contactor plate at the end of the shaft, exiting the other end for power.

UPDATE:
Done.
Never took apart and cleaned out a motor before- degreased, lubed the bearings, and a coat of gray Rustoleum...and did a lot of reading last night about induction start, induction run motors

I soldered extensions onto all four leads to give me plenty of working room to test, and re-wire.
A Google search (forum search didn't turn it up!) gave me this thread, from here. Post #13 from Iron Junkie is incredible- it should be a sticky. Did the resistance checks, wired per his instructions and I've identified all the wires, motor runs great for being probably 60 or 70 years old.

http://www.practicalmachinist.com/vb/south-bend-lathes/motor-wires-unidentifiable-247790/

Going to fire her up while waiting for the drum switch.

Which begs my final question...Weren't all 9A's sold with a reversing drum switch? If so, this motor is old enough to be- but isn't- original as it took some digging and re-working of the leads.

I think you'd find that not all lathes were sold with a motor and associated electrical stuff. In your case, the lathe could very well have come with the motor and switch but "bad things happen to good lathes" so there's no way of knowing what could have happened to the switchgear over the years.