No announcement yet.

Milling machine rotary cam switch

  • Filter
  • Time
  • Show
Clear All
new posts

  • Milling machine rotary cam switch

    Newbie stumped by wiring rotary cam switch for Enco mill/drill. The machine was wired incorrectly, I assume, when I purchased it used. It would run in forward but not in reverse. I have dismantled the switch and labeled what was previously wired. Attached are pictures of the (6) wire motor with jumpers that were installed. Also included is a new rotary switch that I bought just in case the original was fried. The motor schematic is included showing the (6) wires with the only changed being the brown wire instead of orange as indicated on the schematic. Also included is a switch wiring schematic that I found on the internet with similar set-up but is different that how the original was wired. It has a six pole set-up as the original. I would like to stay with the same switch as it is framed into the machine. Thank you for any guidance.

  • #2
    Grin .. even though we were sloppy seconds as far as your choice of forums goes, you finally ended up in the right
    place. I am sure you will get a good answer here.

    I noticed how they slammed the door in your face over on the other forum.

    You are welcome here.
    John Titor, when are you.


    • #3
      I saw that too..


      • #4
        Welcome to the right forum. You will find things a lot more friendly to home shop people and their problems here.

        OK, for your problem. First, I would not assume that the machine was wired improperly. Granted, it may be, but we should eliminate other things first.

        You have a replacement switch. Is it an exact replacement: same make and model? If so, I would install it and see what happens. This is the easiest thing to do from where you presently are.

        If that does not fix things, then we need to go further.
        Paul A.

        Make it fit.
        You can't win and there is a penalty for trying!


        • #5
          Are you saying that the switches you have (either the one on the machine OR the new one) are NOT like the schematic?

          because what we need to know is how the one you will actually be using operates. You can make a table for which ever you will use by checking with an ohmmeter.

          The schematic is correct for a reversing switch. The main windings are connected the same way in either fwd OR reverse. The difference is the start winding, which is connected one way in fwd, and the other in reverse.

          Single phase motors run either way, the way you reverse them is by letting them stop and then starting in the other direction. You can even do it with a rope start.

          The start winding determines which way the motor goes. When you reverse the wires, the start torque reverses direction.

          As for PM, "da rulz is da rulz".... you might have been fine if you had NOT mentioned the brand, AND you had posted it in the motors and transformers area....
          Last edited by J Tiers; 01-05-2016, 09:14 PM.

          Keep eye on ball.
          Hashim Khan


          • #6
            Thanks for accepting me into the circle of friends. I guess us lowly civil engineers didn't nearly match up to those mechanicals...LOL. Here are the facts:

            The new switch is the same as old, (6) pole
            The wiring for motor phase is correct, 120V, for the junction box
            The motor will be used in F and R.
            I understand the motor schematic as far as capacitors and windings but not the wiring going into the switch which was obviously incorrect when I bought the machine (if it goes forward it should go backward correct?).
            The color coded wires are the same except for the orange (schematic) and brown (machine).
            I understand testing for continuity but do not know where wires go on switch to simply make it go forward and reverse.
            Do not want to risk loss of life due to "I can figure out anything" syndrome.

            I have searched high and wide on the web but all has been futile. I even thought the guys over at a large commercial electric motor company in my area could solve it but...a lot of head scratching. Maybe liability issues. I did come up with that switch schematic but it make no sense. Thanks again for any direction.


            • #7
              I think Paul had a good suggestion. It only takes a couple mins to hook the new switch up exactly like the old switch
              and see what happens. The original switch may have developed a fault (burnt contact etc.) which is preventing the
              reverse function from working .

              This is a really good first troubleshooting step.
              John Titor, when are you.


              • #8
                Hey, we need you civil guys.
                Mechanicals make the bombs,
                civils make the targets.
                To correct, I am only semi-friendly
                until you get to know me.
                As to your name,
                Do you have a micrometer collection?



                • #9
                  Ok, first time poster here, so please be kind I'm definitely an amateur when it comes to machining, but know enough electricity to be dangerous. (Didn't use a barrel switch, but my lathe does reverse even though it did not originally. Reverse is nearly useless with a threaded spindle though )

                  I'm not seeing the red wire from the motor. Are you sure that diagram actually matches your motor?

                  If the diagrams are correct, you'd connect the black and white line in wires to switch terminals 1 & 3. Blue and Orange from the motor go to terminal 2; white and yellow to terminal 4.
                  Assuming CCW is "forward", red goes to terminal 8, brown (or orange) goes to terminal 12. If the motor doesn't run the way you expected, reverse these two connections.

                  Jumpers connect terminals 1, 5 and 9 together; also 3, 7 and 11. Single jumper between 6 and 8; another between 10 and 12.

                  Assuming your power has a suitable fuse or circuit breaker installed, you probably won't damage anything too much even if you power it up wired wrong. Just be prepared to yank the plug out of the wall if anything weird happens (like it buzzes with the switch off). But most likely, a mistake will just harmlessly blow the breaker (or fuse), perhaps after a few seconds of loud buzzing.

                  PS, I'm not sure what would happen with that run capacitor if you quickly flipped the switch from forward to reverse while the motor was still spinning. Might burn the cap up; but I'm pretty sure the motor will not reverse under those conditions (as noted above). My old Atlas lathe motor only has a start capacitor, and will happily keep running either direction if I don't stop it before selecting the other direction.
                  Last edited by TR3driver; 01-06-2016, 12:17 AM.


                  • #10
                    it takes even LESS time to check if the connections the switch makes match the printed table of positions and connections. If so, good. If not, then make a table for the switch in question, and then see how it has to connect, using the printed table and schematic as a guide.

                    Even if the numbers are different, if the function is the same, then you can see how to substitute numbers to get the same operation.

                    Keep eye on ball.
                    Hashim Khan


                    • #11
                      Thanks for the help guys that was lickidy split. Let me try these angles and I will get back to you...if everything goes okay.


                      • #12
                        Originally posted by palmers8 View Post
                        ...similar set-up but is different that how the original was wired.
                        So how was the original wired ?

                        The second picture (showing 'the jumpers that were installed') only has 5 jumpers - I don't think there's a way of wiring the switch to use only 5, so had one been removed already ?




                        • #13
                          I have all of the wires labeled from the old switch. Completely different than the wiring on the switch schematic above. I tried wiring both ways, the original wiring AND the wiring recommended above and NOTHING. No fish frying noises, breaker clicks...nothing. Yes, I do have 120V at the supply going into the switch. I think you may be correct about the jumpers. Did I possibly lose a jumper in the confusion??? Will not even go in the forward direction as originally wired. Is the switch possibly different? It is numbered exactly the same as the original switch and screws into the frame exactly the same. Everything is dimensionally the same for both switches.

                          I tested the continuity of the switch and here is what I found:
                          Forward = 3-4, 7-8 and 11-12
                          Reverse = 1-2 and 5-6

                          Also,if we look at the above picture at the connections in the junction box you will see that the brown, blue and yellow wires are not even connected to the motor in the cable from the junction box to the switch. I would assume that these do not even need to be connected, correct?

                          Thanks for your continued support.


                          • #14
                            So.... it appears the switch may be unsuitable for the application.

                            But, wait...... what about 9-10? I think you left them out. Maybe that connection does not work?

                            Keep eye on ball.
                            Hashim Khan


                            • #15
                              It got to, it is the same exact switch. Also, brown, blue and yellow aren't even hooked up in the junction box. I think someone hooked them up just to hook them up. There are wire nuts on them in the box.