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120 To 240 Volt Issue.

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  • 120 To 240 Volt Issue.

    My daughter picked up an antique tapper (like a drill press) from the late 1890's or the early 1900's and there is a motor from the early 1930's to the 1950's, and it was running off of 110V but the motor plate says it will work with 220.

    I pulled the cover and there are 4 wires, but they are all black, and they all have a small aluminum band wrapped around and crimped to them numbered #1,#2,#3, and #4.

    The two that were wired to the 120V power cord were #1 and #4.
    The #2 and #3 were wired together under the cover.

    My MIG welder and powder coating oven both use 240V so I want to wire the "NEW" drill press for 240V as well.

    Any one know which wires go to the two (out of phase) 120V power, the neutral and ground?

    I'm used to the red and black both going to either of the two phases of 120V, the white goes to neutral and the green is the case Ground.

    The tag has this info and the underlined parts are the blank area that was stamped.

    411----Wagner Electric Corp----401
    Alternating Current Motor type RA
    Frame 203 MOD C65---M---181
    1HP 1750 RPM Phase 60 cycles
    110V 13.2amps----220V 6.6amps
    Cont. rating 40 C NO 2A
    Code G SK Protector 27E

    If I had to tear it apart, how do I tell where the two power wires go and what to do with the remaining wires?

    It looks somewhat like the one pictured here with the lube cups and all, that is if the picture works.

    Last edited by archangel; 06-21-2008, 11:49 PM.

  • #2
    Re: 120 To 240 Volt Issue.

    Now I see there is an electronics section on this forum.
    Perhaps I should have posted there?


    • #3
      Re: 120 To 240 Volt Issue.

      Is there a cover where the wires come out? If yes, clean it up and look at it carefully. There should be a wiring diagram on it. Personally, I would leave the motor as is. If you mess up and burn up an antique motor you'll really be *&^%$#@ away.

      By the way the numbers are what tell which wire is which. With motors it's common practice to number the wires rather than color code them.

      With the motor wired up as it is now, does it startup slowly and take 5 or more seconds to reach full speed? If yes, it may already be wired for 240 Volts but I wouldn't count on it. If on the other hand it starts up and reaches full speed quickly running on 120 Volts, then it is wired correctly for 120 Volts AC. Old repulsion start / induction run motors such as your's will start up and run on 120 Volts when wired for 240, but they are rather sluggish. On the other hand if wired for 120 and connected to 240 the motor would blast off with a big jump and most likely blow fuses or trip a circuit breaker fast. Please don't take any foolish chances. If it starts up well and runs good on 120, please leave it as it is and bring power over to the motor. A good electric motor repair shop should be able to figure out how to wire it up for 240 Volts if you get stuck. Normally, I would think there would be more than just 4 wires. I wish I still had my old 1-1/2 HP Wagner from the same era. I could really help you out, but sadly it was sold some time ago.
      Last edited by Woussko; 06-22-2008, 05:27 PM.


      • #4
        Re: 120 To 240 Volt Issue.

        Sound like it's already wired for 240v. There are 2 windings and they are wired either in parallel for 120v, or in series for 240v.


        • #5
          Re: 120 To 240 Volt Issue.


          That's what I've been thinking and why I wanted him/her to try starting and running the motor on 120 Volts. If it starts up slowly and runs really quiet (little groaning) then it may well be wired up for 240 now. If on the other hand it starts up fast and does growl, I wouldn't want to try it on 240 without being more sure of things.

          I wonder if he/she has access to a clamp-on AC Ammeter. If yes, a check of running current with it running under no load and on 120 Volts should tell us more.

          By the way when run on correct Voltage those old motors could easy put out about double the rated power for a few seconds every 15 minutes or so. They had huge service factors. Put another way it can grunt down for a few seconds and put out far more than rated power. Today's junky motors and especially the ones from over in China are overrated.
          Last edited by Woussko; 06-22-2008, 05:30 PM.


          • #6
            Re: 120 To 240 Volt Issue.

            He can also separate the 4 wires and check them with an ohm meter to find the 2 coil windings, and then tie them in series for 240V. But, I think that's how it's wired now.


            • #7
              Re: 120 To 240 Volt Issue.


              yeah those old motors had a high service factor for sure. I don't trust the ratings on most of the new junk. Baldor still makes a good motor, but not sure about most of the others...