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Re: Variable speed motors

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  • auto249243
    ... I have bogged down the motor at full power. From a no load rpm 500 to a loaded 300 rpm, drawing more continuous current than my power supply could handle.
    Message 1 of 31 , May 1, 2011
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      --- In taigtools@yahoogroups.com, "Dean" <deanofid@...> wrote:

      > I don't really understand why a jack shaft would be needed for this motor at all. It's VARIABLE speed already, and has more torque than the Taig lathe needs as it is.
      > With the stock Taig pulleys it will run the spindle at 60 rpm with enough power to take a hefty cut. At 200 rpm it will slip the belt before the motor stalls.
      >
      I have bogged down the motor at full power. From a no load rpm 500 to a loaded 300 rpm, drawing more continuous current than my power supply could handle. 10-15 minutes of cutting overheated and burned out 2 of the 5 transformers. I don't recall for sure, but I think I was taking 25-30 thousandths at a time. The transformers are 18V in series to get the 90v for the motor. I got them surplus, so I am not positive what the current rating on them is. They were listed as 3-3.5 amps, which in retrospect is most likely about right. Obviously, I need to back off a bit! Plucking the belt will give a dull middle C, so my belt tension is fairly tight.

      I have seen Bentley's site, and am considering buying a second motor to do the bearing replacement. He does very nice work.
    • auto249243
      ... I was cutting aluminum 1 down to 1/4 . The motor was running max rpm(90V). The sleeve bearing tends to get hot. I am considering drill a tiny hole in
      Message 31 of 31 , May 8, 2011
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        --- In taigtools@yahoogroups.com, "Dean" <deanofid@...> wrote:

        >
        > It sounds like you are feeding the motor full current all the time. Running at max RPM?
        > I use a controller with mine. You can't stop it, and it doesn't get excessively hot. I've use the same controller since buying the motor. No jackshaft needed, just the stock Taig pulleys.
        >
        > Dean
        >
        I was cutting aluminum 1" down to 1/4". The motor was running max rpm(90V). The sleeve bearing tends to get hot. I am considering drill a tiny hole in the housing so I can give it some oil.
        My guess is that I was pulling 4-5+ amps. I had a 6 amp fuse in the power supply, and it blew when the transformers shorted. I used a jack shaft because I was fixated on getting the rated horsepower out of the motor. Probably not necessary.
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