Anybody knowledgeable about OLD AC motors?

Discussion in 'Non-audio related DIY' started by ghazzer, Nov 17, 2017.

  1. soundmotor

    soundmotor super modified Subscriber

    Turning 0.125" stock would be huge on a jeweler/watchmaker lathe.
     

     

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  2. soundmotor

    soundmotor super modified Subscriber

    Does it actually say VAC on it? Many motors (especially that old) are universal and run on either AC or DC.
     
  3. BigElCat

    BigElCat AK Subscriber Subscriber

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    Duly noted.

    It appears to be an actual lathe motor.
     
  4. Te-Te

    Te-Te Learning never exhausts the mind. Subscriber

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    The Motor made me think of my Shopsmith with the 3 step pulley. Curious what the one you have would've been used for.


    . IMG_2368.JPG IMG_2369.JPG IMG_2370.JPG
     
  5. ghazzer

    ghazzer Sansui addict Subscriber

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    soundmotor: The label on the motor is shown in post #1, which lists the volts as 110 and the amperage as 0.35. I made the assumption that it was not 110vdc. There is a bakelite switch in the base that swaps the field leads to reverse the rotation of the motor. It worked OK plugged into the 115vac outlet in my house, but I don't think I'll try it with 110vdc.

    The motor came with this lathe.
    P1060186A.jpg

    I have cleaned up the original wiring, spliced in new wires and run those to the switches in the photo.

    Right now I have opened the housing and am working on the inside. The internal wiring is not "pretty", but it ain't broke and I'm making no attempt to fix it. I finally got the brushes out (0.146" X 0.146" X0.625") and will probably have to size new ones with emery paper to fit & slide freely. I have cleaned up the commutator and may need to smooth it a little. Today I bought a can of CRC Lectra Clean and will use that to clean out as much of the carbon dust and grime as practical.

    I have learned of other things that could be done as part of a motor refurb, but they are beyond my capabilities.
     
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  6. soundmotor

    soundmotor super modified Subscriber

    Almost certainly it's a universal motor, AC or DC.

    Not uncommon, electric fans & plug-in power tools quite often still have them. They are easy to manufacture and don't use magnets.
     

     

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  7. Pio1980

    Pio1980 AK Member Subscriber

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    Sewing machine motor and controller. Alternatively, a dental lab bemch engine and controller.
     
  8. ghazzer

    ghazzer Sansui addict Subscriber

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    Pio: I mentioned before that I ordered a sewing machine motor as a backup in case the refurb of the vintage motor doesn't work out. The sewing machine motor turns at 6,000rpm and the vintage motor turns at 3,500. Assuming that the lathe mfg (Wolf, Jahn in Germany) knew what they were doing, I am taking steps to reduce the 6,000 to ~3,000 with a 2:1 pulley reduction.

    I turned these two pulleys today at the wood shop. I think I can put them together on a shaft with bearings in a jig and link it between the sewing machine motor and the lathe.
    P1060218.jpg

    Hopefully I can find replacement brushes and get the vintage motor running AOK.
     
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  9. soundmotor

    soundmotor super modified Subscriber

    Or use a DC motor & controller w/ speed variability from ~100-7500RPM.
     
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  10. gadget73

    gadget73 junk junkie Subscriber

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    How are you going to do the speed steps? One solution would be to pull the step pulley off the stock motor and mount it with your smaller wood pulley on an intermediate bearing. Drive the small pulley off the big pulley attached to the motor. You'd need to build an appropriate countershaft bracket with supports and bearings to get that done of course.

    DC motor would probably be a cleaner and smoother solution. Lots of torque at slow speed, and DC runs very smooth.

    personally I'd just knock the original motor apart and lube it up. Motors aren't rocket surgery. The most complex thing about this one is the brushes, and if they can be removed you're golden. Holding the brushes back to assemble the motor is the hardest part.
     
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  11. ghazzer

    ghazzer Sansui addict Subscriber

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    I'd prefer to be able to set the speed and leave it. Control of my foot may have been rock solid at 32, but that was 40 years ago.

    The motor is apart now. I plan to clean the carbon dust up with CRC's Lectra Clean, but it has been snowing all day.
    P1060203.jpg

    The commutator cleaned up nicely but may still need some burnishing.
    P1060214.jpg

    The brushes (3:00 & 9:00) are spring loaded behind a cap screw and should be no problem. Shadows at 12:00 & 6:00 are from two lamps on the sides.
    P1060209.jpg

    I haven't searched for brushes yet, but do have high hopes of getting this motor refurbed enough for my purposes.
     
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  12. soundmotor

    soundmotor super modified Subscriber

    When turning different materials (metal vs. plastic) you don't have to change pulleys to change speed.
     
  13. ghazzer

    ghazzer Sansui addict Subscriber

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    I guess I am missing something here, besides being a flat dumb novice wrt lathes. How else would you change speeds if you did not want to change the voltage to the motor?

    Hell, I don't even know the reasons to change speed if not because of the type/density of the material.
     
  14. Pio1980

    Pio1980 AK Member Subscriber

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    It's done on the multi ratio pulley set from a fixed motor speed.
     
  15. ghazzer

    ghazzer Sansui addict Subscriber

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    OK, I've learned one tiny thing more. I mistakenly read that "change pulleys to change speed" meant moving the drive belt to a different groove on the multi ratio pulley. One of these years I will remember to read through comments more than once, until I am convinced I understand the wording.

    I have accumulated several articles and books about the use, care and maintenance of lathes, and even read some of them. Much of it will have to be re-read after I get the lathe running and I can better understand some of the references and instructions.
     
  16. N8Nagel

    N8Nagel AK Subscriber Subscriber

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    reading through this thread for the first time... nice job bringing that thing back.

    I am, however, having flashbacks to doing very similar work on old wiper motors, heater blower motors, etc... been a few years since I did anything like that, and yours looks a little more involved...
     
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  17. ghazzer

    ghazzer Sansui addict Subscriber

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    I'm hoping that it will be less involved as soon as I take the time to clean out the carbon dust. Wheew - nasty stuff.

    Brushes should arrive before Christmas and then I can try my hand at resizing them to fit the channels in this vintage beauty.
     
  18. ghazzer

    ghazzer Sansui addict Subscriber

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    One set of brushed arrived and I quickly realized that I didn't think things through well enough. The brushes I need are 5/32" (0.156") square and longer than 5/8". I couldn't find that on fleabay so I settled for ordering 4ea of 6mm (0.236") square and 20mm (0.787") long and figured out a good way to "sand" the sides to size & square with emery paper.

    As soon as they were out of the bag I saw the problem: The O.D. of the compression spring is also 6mm, and I cannot sand them down.
    P1060219.jpg

    The originals have a "turned head" at one end for the spring to fit over - difficult to reproduce. This is important because it is the path for the electricity to get to the brushes. The second set is probably on a slow boat from China, MUCH cheaper, and at 4mmX4mmX18mm should not require any sanding more than a touchup for fit.
     
  19. gadget73

    gadget73 junk junkie Subscriber

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    If yours are the smaller ones pictured, those don't look worn enough to worry about honestly. Unless the bump where the spring goes is broken on the one?

    Looks to be a series wound motor, so if you need speed control finer than the pulley steps, a variac or a sewing machine pedal would do the trick. Clean the bearing wells out and add some oil, you should be good to go. Little motors are simple and easy, provided someone hasn't powered them without the rotor spinning.
     
  20. ghazzer

    ghazzer Sansui addict Subscriber

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    Maybe I am being overly cautious, but I want to do what I can to overhaul and preserve this motor before I start using it with the lathe. The foot pedal controller with the original motor is toast. The backup sewing machine motor came with a controller and I can adapt that to the original motor if need be.

    The 2:1 pulley reduction is being planned so that the Sewing machine motor can be run at the upper range of voltages w/o delivering the higher rpms to the lathe.

    If you use a controller to throttle the speed from 6,000rpm down to say 2,000rpm, what does that do to the torque? Is it linear, or 1/3 of full torque, or is there a curve?
     

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