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Electrical wiring ??

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  • Electrical wiring ??

    Hi all, OK, I'll admit that I'm somewhat electrically inept. That said, I have a Powermatic 14" band saw that had a 3-phase motor in it. I don't have 3-phase at home so I ordered a new 1-phase motor for it. After installing the new motor the machine will pop a 30 amp breaker. The motor will run for a few seconds then it pops the breaker. What am I doing wrong here? I've got 200 amp service do the shop and it's no where close to being maxed out. It's got 10/4 wire to the plug and a 50 amp plug. I think I think I've got it wired correctly (white/white, red/red, black/black, green/bare). The motor is wired L1/white, L2/ red, L3/ black. The switch on the machine has 3-phase manual motor starter printed on the front of it. Anybody have an idea what is wrong with this damn thing?? Thanks, Tim

  • #2
    Toss the machine in the back of you pick-up and take it to the motor guy and have him fix it. Then the problem is fixed.

    There's some crafty electrical types on here and they'll try their best to help you but as I read your post you have a real electrical tangle.

    You can use the three phase starter on single phase but right now you have the white on L3. You never break the white (neutral) conductor. That do you have wired to it?

    The Red/Black should go through the starter contact to the motor leads.

    If you have a light on the machine and maybe a convenience outlet, use the white/neutral to provide the 115 V from the red or black. Provide the 115 volt circuit with separate 20 amp fuse or molded case circuit breaker in a box on the machine.


    • #3
      How many HP is the motor? Are you using the starter that is set up for the three phase motor? Too big a motor will trip a breaker and the motor will not run properly if set through the phase starter. Good luck.


      • #4
        Voltage connections?

        Mechanical problem? A 1/2 hp motor will draw amps of a ten horse when it is locked down.

        Do you have a electrician friend locally?

        If not, take pictures of motor taps and post them. Hooking a motor up wrong can burn it out. Even for a instant.

        Normally 220 wiring home type, black L1, White L2 (220 second leg) bare or green is saftey ground that carries no current.

        Normally 120 wiring, black L1, white neutral or ground return for motor, green or bare is saftey wire that carries no current.

        Normal 3phase wiring, black 120 + red 120 = 240 + blue 120 = 240 3 phase.. you have 240 between each two legs. AND then you have the HIGH leg type system reading to ground or neutral, 120 120 180 or so volts.. leg to leg 240, 240, 240.. Yes strange and it burns up a lot of lights and other things. Since most electricians don't take time to notice the voltage, all they see is a open space in the panel on the high leg.

        Lesson #1 complete, please mail a check to:

        HA HA.. see ya, wish ya the best

        David.. gotta run, something shiny...

        NOTE: inside single phase motors are internal taps that do not hook up outside the motor. Red wire unless you have 220 tapped is a internal wire. Refer to motor plate for connections, post pictures of each box and "We" will try to help.. Lots more smarter people here than me..4

        [This message has been edited by ibewgypsie (edited 06-06-2004).]


        • #5
          Called an electrician buddy of mine last nite. He came over an checked it out for me and guess what! I hooked up the motor wrong and it's smoked!! Another slightly expensive lesson learned. So now I know how to hook it up correctly (after my pal got done laughing at me). I am a moron!!!! Thanks for all your help guys. Tim


          • #6
            Not knowing something does not make you a moron.

            Not trying makes you lazy.

            Spending money like that is expensive form of education.

            You're lucky, lots of people burn down houses fooling with electricity and "not knowing what they are doing" You just lost a minor thing, not everything you own.