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motor speed control

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  • motor speed control

    I have a 60-odd-year-old Gorton vertical mill, 9x32 table. It's about 4/5 the size of a Bridgeport, and came with micrometer downfeed for the quill and a second motor and change gears in the knee to move the table. It'd be a pretty little thing, if some previous owner hadn't painted it with lumpy greenish-pink paint that looks like used kitty litter mixed with barf.

    When I got it in 1993 I ran into the "three phase at home" problem. I replaced the three phase motor with a 2hp single phase, which has worked, but I'd like for the table motor to work now. And now that I have a big rotary convertor, there's no reason not to make it work... except the big (2x3 feet?) box full of contactors and relays has slunk away after all these years.

    I still have the original three-phase spindle motor. Oh, there's a third three-phase motor, for the coolant pump setup.

    Ssoooo... my options are:

    a) convert the table and coolant pump to single phase

    b) buy a carload of contactors and rewire it all back to three phase

    c) get fancy and go for variable speed motors

    How could I go about getting variable speed out of the three phase motors? Or would it be better to go to single phase, or even DC?

  • #2
    Simple, use a VFD for each of the 3ph motors that you want speed control on.
    Master Floor Sweeper


    • #3
      Easy, use a VFD. (for each of the 3ph motors that you want speed control on.)
      Free software for calculating bolt circles and similar: Click Here


      • #4
        Looks like a concensus!


        • #5
          I suggest a VFD too. Does that make ir "consensuser"?

          Can't beat them VFD's for making a real controllable motor out of a plain vanilla single speed boring tedious three phase motor.