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Thread: 3 phase motor question

  1. #1
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    3 phase motor question

    My new bandsaw has a motor that is switched to run at two speeds. The pigtail off the motor with a four prong plug has 5 wires in it 1x 1g 2y 1w. I do not know if the motor is delta or y 3 phase. I am running it off a rotary phase converter that only has x,y,g. My question is what do I do with the w?

  2. #2
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    I'm not sure on this one. Normal 3 phase consists of 4 wires - 3 power and a ground. Seems like anything to do with switching speeds would happen up stream from the plug. So it's possible someone bought the wrong wire and only had 4 hooked up.... yeah don't ask me how I know that happens

    Is this a new, new machine, or new to you? If new I'd think a call to the manufacturer is in order. If used look to see if only 4 of the wires were stripped for the plug. Alternatively check the wiring to see whats connected at the other end of the plug. If none of this helps, hopefully someone will come along with better advice.

    good luck,
    JeffD

  3. #3
    Quote Originally Posted by Michael Todrin View Post
    My new bandsaw has a motor that is switched to run at two speeds. The pigtail off the motor with a four prong plug has 5 wires in it 1x 1g 2y 1w. I do not know if the motor is delta or y 3 phase. I am running it off a rotary phase converter that only has x,y,g. My question is what do I do with the w?
    Does the machine have a light or something that would work on single phase? You may have three hot wires, one neutral and one ground. It would need the neutral if there is something single phase on the machine.

  4. #4
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    Quote Originally Posted by Michael Todrin View Post
    My new bandsaw has a motor that is switched to run at two speeds. The pigtail off the motor with a four prong plug has 5 wires in it 1x 1g 2y 1w. I do not know if the motor is delta or y 3 phase. I am running it off a rotary phase converter that only has x,y,g. My question is what do I do with the w?
    Most 3 phase motors have a plate on the motor that diagrams how to run the wiring. You might want to look for it to see if the extra wires are related to the different speeds.

  5. #5
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    Quote Originally Posted by Michael Todrin View Post
    My new bandsaw has a motor that is switched to run at two speeds. The pigtail off the motor with a four prong plug has 5 wires in it 1x 1g 2y 1w. I do not know if the motor is delta or y 3 phase. I am running it off a rotary phase converter that only has x,y,g. My question is what do I do with the w?
    What does the motor pigtail plug into?

    regards, Rod.

  6. #6
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    Thanks for all your replies.

    Jeff, it is a new to me machine. I have contacted the company in Germany and am waiting on a reply from them.

    Edward, There is no light or single phase supply.

    Scott, I will check the motor plate and see what I can see.

    Rod, The pigtail is plugged into a rotary phase converter from American Rotary.
    Last edited by Michael Todrin; 10-16-2019 at 2:32 PM. Reason: I was not correct

  7. #7
    You really need to trace that wire all the way from that plug through the inputs, switch, control circuit etc.

    Its probably needed, but I would have used a jumper in the terminal block to pick it up, vs. two shoved under that terminal in the plug.

  8. #8
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    So I traced the wire and found that it runs to an unused switch for a dust collector. One question answered. In looking at the motor plate it shows the motor as delta for low speed and wye for high speed setting. The low speed runs but the high speed does not, the motor just hums. Any ideas as to why?

    Thanks

    Michael

  9. #9
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    Quote Originally Posted by Michael Todrin View Post
    ..looking at the motor plate...
    If you post a picture of it others could see it too. That can help with the accuracy of the responses.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  10. #10
    Quote Originally Posted by Michael Todrin View Post
    So I traced the wire and found that it runs to an unused switch for a dust collector. One question answered. In looking at the motor plate it shows the motor as delta for low speed and wye for high speed setting. The low speed runs but the high speed does not, the motor just hums. Any ideas as to why?

    Thanks

    Michael
    It's only got 2 out of the three legs then, a meter should answer which ones.

  11. #11
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    Got it up and running! Thanks everyone for the help. I ended up taking apart all the connections, cleaning and tightening and it all works. Something must have shook loose in transport.

  12. #12
    Just browsing Google, I found this about 2 speed 3ph motors. Dahlander pole changing motor.

    If you google Dahlander 2 speed motor you'll find plenty.

    Mike
    Last edited by Mike Henderson; 10-17-2019 at 2:54 PM.
    Go into the world and do well. But more importantly, go into the world and do good.

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