9" Atlas Lathe Motor Wiring

[J Tiers]

The cover is what I mean...... the one with the nutty binding posts on it.

Yes, the capacitor COULD be a donut shaped device in an end bell.

There are all kinds of motors that have been made. I had a Milwaukee die filer with an ancient motor on it. It had a rectangular case on it, so I thought " capacitor case"....

When I opened it up, I found a very large ceramic resistor.... it was a resistance-start motor. Like a split-phase, but with an external resistor to add the resistance required to shift phase. Obsolete for 70 years or so.

So that could be nearly anything. I am not familiar with the type CAH, and google wasn't helpful, need to mess with the search terms....

A really simple solution is a $5 garage sale motor......... so long as it looks newish and it spins free it is almost certainly good.....

[Paul_NJ]

How about that plate which is visible in the photo of the end housing? The plate which covers the lower half. Two screws hold it on. That's where the brushes would be if it was something goofy like an induction-repulsion motor. But if it was the nameplate would most likely say so.

Here is a photo of a Westinghouse Type CAH (not mine).



It shows the wires hooked up in what looks like an ordinary way for a split-phase or capacitor start motor. Even though no capacitor is visible it may still be a capacitor start motor. The capacitor on the oldies was sometimes inside the end housing. More modern capacitor start motors have an obvious lump on the side so we can usually identify them at a glance. A split phase motor has no capacitor at all. It relies on winding resistance for the phase shift - an inductive/resistive time constant rather than a capacitive/resistive or capacitive/inductive one.

When wiring it up you don't care if it's capacitor start or split phase. You have to get current to the main winding, and current to the start winding. You swap the start wires around to reverse it.

When facing a real mystery motor I just make my best guess as to what's what with the ohmmeter, then connect it momentarily. If it doesn't start right away (like, half a second or less) I disconnect it and try something else. With 4 wires there aren't too many ways you can go wrong. If you take it to somebody else to do it, you won't learn anything about motors.

Terrific! Thanks for finding and posting the photo of another CAH motor . . . Now I see what the unused terminal posts are for. Also suggests a convenient solution to the frayed wire issue . . . I can just cut the old wires, wrap the terminals, and use new wire from there.

[Dawai]

I use the sniffer approach to buying a motor.

I found a guy at a flea market, he had a table of milwaukee drills.. I went through them sniffing for burned windings.. found one that stunk the least. Bought it. I got a near new drill for $5. Some of the others, you could see purple discoloration on the windings.

[Paul_NJ]

Hello Again!

Success! Here's an update. Four wires leaving motor. Let's label them as follows:

A B
C D

Checked continuity as suggested above: A+D, B+C have continuity

Facing shaft:

Motor Runs CW: A+C, B+D
Motor Runs CCW: A+B, C+D

Runs fine; current draw OK, slight grinding sound on last couple revolutions when stopping.

Thanks for all of your help.

Paul

[Dawai]

Flip the lil caps and add oil...

If the noise is rust inside the motor and is not cleaned out, it may grind insulation off..

I had a problem recently with some large steppers in my shop. They had been stored in the non-climate controlled shelf. Rust on the inside. Not good.

gotta love oiled babbit bearings.. it will run a long time. I recently looked in on a 2 stroke motor with pressed babbit and brass bearings.. the crankshaft had dropped 1/8" and the points no longer would adjust enough to compensate.

[J Tiers]

Runs fine; current draw OK, slight grinding sound on last couple revolutions when stopping.

Thanks for all of your help.

Paul

Probably the centrifugal switch bearing..... the switch is stationary, the speed sensor rotates.... so when it slows down and closes the switch, the rotating part rubs on the stationary part..... You probably hear a "click" right before that.

No problem on the help....... get some, give some..... all works out.

[slowtwitch]

I worked in a Westinghouse Motor Repair shop (in Philadephia) many years ago. They use to give us 5.14 hrs to rewind one those. You brought back some good memories

pete

[Paul_NJ]

I worked in a Westinghouse Motor Repair shop (in Philadephia) many years ago. They use to give us 5.14 hrs to rewind one those. You brought back some good memories

pete

5.14 hrs? . . . . sounds like they had a stopwatch going . . . talk about pressure! That doesn't sound like a fun time.

[slowtwitch]

Paul,

believe it or not, we use to wind them by hand. Actually count each turn in a coil and did it with time to spare The older motors were easier to wind than the newer ones. Now, rewinding one of the generators at the Hover dam took a bit longer

pete

[fuzzy]

Atlas lathe motor reverse

My Atlas 10" lathe motor (also Atlas) has three terminals (1,2,3) I found that to reverse it you change the internal wire from 3 to1. I am going to try and find a toggle switch to reverse the motor.