Anybody knowledgeable about OLD AC motors?

ghazzer

Senior Member
And I do mean OLD. I think this one dates to the first quarter of the last century.
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It is a Kendrick & Davis, "The Special". 110 VAC, 0.35Amps, 3500 rpm, 2 pole. The insulation on the wires is black cloth, and it is crumbling. I have covered all the exposed wiring & insulation with heat shrink tubing, but have NOT opened the housing. It seems to run OK, but I have not powered it on for more than a couple of short spurts.

I can access the bushings but cannot get them to come out.
 
Is there a specific question? Might want to check inside for more of that brittle insulated wire.. Otherwise, if it runs, try to lube it, motors this vintage often have a little place to put oil every so often.
 
Yes, the title is asking for anyone with knowledge of this type/style of motor. I will not be cracking the shell just to see what the inside looks like. If you can offer me some specific information I will grateful to learn more.
 
Is there a specific question?

Perhaps you are correct. My thoughts were to close to my problem and I failed to consider that others cannot read minds.

Specifically: Is there anyone on AK who has opened one of these (or similar) and worked on the wiring, brushes, or other internal parts, and is willing to share their knowledge?

Thanks - - -
 
honestly I'd crack it open to lube the bearings and replace the wiring. Is that a brush motor or an induction motor? Brush type I'd expect holders accessible from outside, which makes assembly really easy. There is really not very much inside a motor, but they must have oil. Its probably an oillite type bushing, basically pourous bronze with a felt packing around it. The felt may have fallen apart which makes the oil reserve non-existant. Old oil does get gummy and foul too.
 
First thought was a sewing machine motor, but the three step pulley suggests it might be the motor for a jeweler's lathe. The nice thing about motors is they work pretty much exactly the same as they did 100 years ago. Looks like it has oil holes. Use a thin oil with no solid additives like Teflon and such. Superlube low viscosity oil without PTFE is a good choice.

Ha! Looked 'em up and sure enough, they were in the watch business. Here's a small lathe I recently picked up.
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Saw the title, and said to myself " Sure, I've been working on AC motors manufactured from the 60s to now..."
But Wow is she an oldie... I love it.
Gadget and Conrad seem to have it under control... but I would reiterate to not be afraid of cracking 'er open and lubing and cleaning, and taking a look at the bushings... and replacing the cord with a modern one. Unless you are going to sell it, then I'd leave the old cord on it. What are you going to do with it? Are they sleeve bushings?
 
Looks like an induction motor to me (3500RPM),,, seems brush holders would be outside the case (but they could be inside also),, as they are on my Foredom, and jewelers lathe... However, they are DC motors, which are usually plugged in to a foot operated rheostat to control speed,,,
Open it and check for brushes, oil it. and run it another 50 years!!
 
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Yes, it is a brush motor for a watchmaker's lathe. I have ordered a sewing machine motor as a possible replacement, and will not crack this one open until I have the replacement up& running. I've seen way too many times that someone has jumped in and then found the walls crashing in around them.

I sprayed the bearings with CRC 2-26 and then turned the motor with a slow drill motor and a rubber band over the pulleys. It may be quieter, but definitely not silent.

There is a rational probability that I could open it, find everything in reasonable order, clean it up, replace the wiring, find brushes to fit & replace them, check the bearings, then get it all back together AOK. However, it only takes one or two of those things to go north and I could be left holding a bag of sh*t. Not having to depend on a working motor after the repairs will somewhat increase my probability of success.

Meanwhile I am hoping that a helpful member with experience shows up.
 
It's a beautiful little motor. Looks like it is the perfect fit for Conrad's lathe.... :)

Conrad, that lathe is just gorgeous. I want it.
 
The motor will go with this lathe if I can get it cleaned up and running smoothly.

This is what the wiring looked like when I got into it. ALL the wires have black cloth insulation and I was using heat shrink tubing to ID them. This "splice" was wrapped with friction tape.

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I've worked on motors a fair bit as an electrician, but time being money, most often the old stuff would simply be replaced, particularly when windings were shot (I never got the chance to actually rewind a motor, that was for the generation of electricians that came before me). However I like that you are interested enough to want to preserve and keep it running, but not opening her up is probably not the best idea. I wouldn't be afraid to, they are pretty simple machines, but they do require maintenance, particularly the senior citizens like this specimen.
 
I have ordered a sewing machine motor that should be able to fill in for this one, assuming that I can get the K&D pulley stack off and moved to the new motor. Then I will clean off my work bench and crack open the K&D. I checked it today and it is only drawing ~280mA when running and is rated at 350mA, so I feel good about that.

The bearings need to be checked out and I am hoping that I can get the brushes out, identify them, and find some replacements.

I suspect that most people who have survived very long in SE Alaska have learned how to do whatever it takes. We really enjoyed our cruise thru there last Fall.
 
I don't think it will have enough power to do any actual work on the lathe.

It will probably spin it just for show, however.
 
You're not going to be making big chips with that lathe. It's a jewelers/clock makers lathe. The motor will be fine for small work.

The .9A motor "should" have more power than the .35A one.

What kind of noise is the motor making?

As far as oil, non-detergent type. 3in1 blue bottle or True Value has 20w and 30w non-detergent compressor oil.
 
The motor was making a little "gravely" noise at low rpm, kinda like there was a little grit in there. It was reduced after a short squirt of CRC 2-26 and a minute or so of un-powered turning with a drill motor and a rubber band.

Ohighway gave me a small vial of turbine oil and some good instructions.

Yesterday I was able to get the drawbar out of the head stock of the lathe, but it will need a little more oil & TLC.
 
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