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Lathe switch help

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  • Lathe switch help

    Guys, can you please help me identifying this lathe switch. I tried to search the internet but can't find anything. The previous owner changed the wiring and I am on the 'last stage' after refurbishing the lathe in total. It looks like he only used the lathe in the 'forward' position because all wires to the 'one side' of the switch were removed.
    The single-phase motor is on a Fragram LHB108 and the same as David 400/Select 816B or Lin Huan lathes.
    There is a loose 'white' wire at the motor and the question arises where it should be connected to. Is there any diagram for wiring this kind of switch and the 'Taiwanese'-made motor? I can't find a 'Drum switch' in South Africa and the wholesaler said it will only be imported next year???

    You may only view thumbnails in this gallery. This gallery has 4 photos.

  • #2
    It appears to me since you are running on 240 volts and the white wire would normally be a neutral wire on 120 volts it is not used in your application. To keep it out of the way.
    Larry - west coast of Canada


    • #3
      Was there a cover plate on the motor connection box? If so, did it have any connection diagram in it?

      I assume you do not have any manual or wiring diagram.
      Paul A.
      SE Texas

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


      • #4
        I can not read any labels on the switches. Is there a reverse button? I have to wonder if the switch is even an OEM part or perhaps it was added by a previous owner - whatever happened to be laying around the shop at the time.

        And, is that motor even reversible? It says it is a single phase, induction motor which may mean it is not. Even the motor may not be OEM. Have you tried swapping any of the wires around? It looks like there may be two windings that are brought out to the connection box: perhaps red and black? Have you disconnected them and checked them out with a multimeter. If they are two windings, you could try reversing one of them and see if the motor reverses.
        Paul A.
        SE Texas

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


        • #5
          I'm thinking that the motor might well not be reversible. The two red and two black leads along the top of the connection block are your motor leads. If the black leads are not just to the run capacitor then you might be able to reverse the motor by swapping the black leads but leave the red the way they are. And if that doesn't do it then put the black wires back and reverse the two red wires. If the motor starts the same way all the time then the starting direction is hard wired or it uses the

          As shown even if the motor is reversible you can't do it with the wires as shown. To make the motor reverse you will need to feed all four of the wires out of the connection box and into the switch box. And if it didn't reverse at all it may be a shaded pole motor that is made to only go one way. It just depends on if it has a starter winding and cut out switch or a starting winding with a starter capacitor.

          The long switch you have there has two black buttons and one red. And there's a good number of connections so I'm going to assume you can wire it to run in forward and back. But I don't see any information on what is what. Or does the center bar with the three contacts in two groups of three move when you hit the buttons on the front? If so the connections are visible with the contact bars dropping onto them or lifting off and we can help you out if you tell us which set moves with each black button. And if it's all three on each block that respond to each button.
          Chilliwack BC, Canada


          • #6
            That wiring is atrocious...

            The switch can do forward and reverse, question is: can the motor?
            Disconnect the red and black wires (noting which way round), and look for continuity on the two reds then the two black - if you have continuity on the pairs (or one pair gives a "kick" on the meter ohms range) it should be reversible.
            To run in both directions you need to power the two windings separately so you can reverse live and neutral on one, the minimum you need is a three-pole switch, which you have! You don't have all the necessary terminal screws though, you'll have to get those somewhere, and you need a connector block with 4 separate terminals in the motor (they can be swapped) , and some 4 + earth to go from switch to motor.. And particularly some clamping cable glands where the cable enters and exits the various boxes

            First though, take a meter to the motor wires!

            Dave H. (the other one)
            Rules are for the obedience of fools, and the guidance of wise men.

            Holbrook Model C Number 13 lathe, Testa 2U universal mill, bikes and tools


            • #7
              Guys, thanks for the replies and I realized that the motor needs to be stripped today to check and test.
              Paul Alciatore, you will remember it is the same lathe referred to in my first 'Musical post'. Nearly done and only 'firing up' now.

              I discovered a very strange switch at the back/fan side of the motor with two 'contact pins' that clicks the moment I connect the motor and releases when you switch off. I am attaching some photos of those components, but I need to explain something first. When I run the motor yesterday it turned only in one directing every time even after swapping the wires. Today, after stripping the one side I found a kind of 'Bakelite/Isolation' square panel with the two contact pins. BUT this panel had one bolt missing and the other one was loose, and I believe it had something to do with the rotation. The contactors are pushed to 'close position' by a 'centrifugal? switch the moment you switch on. Never seen this.
              Cuttings, Larry I agree the white wire should be left out.
              Paul Alciatore, there was no cover plate just the leftovers of a plastic milk jug and wire, no diagram and I am still begging for a manual. The three-button switch got fainted printed letters: The left one REV, centre one STOP and right one FOR. I have seen pictures of Select, David 400 and Lin Huan lathes on the internet with the same type of switch. I checked the wires and the red ones going into the windings are clean and I am adding a layout of the Black wires actually feeding the Capacitor through the rear contactors.

              BCRider I don't know about what effect the rear switch will have on the direction and it bothers me that the switch is a kind of 'Booster' for the capacitor. The operating 3-button switch has two sections with three contact points each. Forward and Reverse, the centre button only 'neutralize' all the small links to an Off position. I believe each set of contactors underneath each Black button must be supplied with a Live and Neutral wire from the wall socket but only swopped on one of the black buttons. Then it must be linked to the motor but furthermore, I don't know how it must be.

              Hopefuldave, Dave, I believe it is still the same motor I used, the lathe is made in Taiwan and the same with the motor. When opening the switch, I found some broken springs and contactor damage. Could it be that they decided to use only Forward and then connected the black and red together? The red wires are good, but the black ones only have continuity if you manually press the ‘two rear contactors’ together. That rear switch is troubling me.

              Thanks for all your advice I really appreciate it.

              PS. I can't upload the Word document with the wiring diagram - can you advise me how to do it, because it is kind of important to see how the Black wires are linked.

              Click image for larger version

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              • #8
                So your last post shows the motor does have a start winding with the capacitor in series with the winding and the switch.
                Once the motor speed exceeds an RPM the switch opens and the start winding is disconnected. These motors will
                almost always reverse by reversing the start windings which are probably the black ones. This means you will have to
                verify that and run the start winding wires out to the switch whose function you will have to determine with a continuity
                checker to see which switch connection does what when the rectangular switch buttons are pushed.

                Your suspicion about abandoning reverse is likely true.


                • #9
                  Yep, what sch said. Almost certain from the pics showing the starting switch and flyweights that open the starting switch that you can reverse this motor. In fact reversing either the black or red leads should do the trick. The point of the reversal is to put the main and starting windings out of phase. And in this case since the running winding only has two leads flipping either should cause the out of phase to switch from leading to lagging and cause the direction to reverse.

                  I'm getting a feeling that the latching function of the buttons is in the top of the box with the buttons themselves. And there is a rocking beam or fingers that push on the center bars of the switches and hold them down until the red button is pushed and the pressure is let off the actual switch bars. That being the case you should be able to get reverse out of this machine.

                  But before you do this I'd try switching around the red or black leads and confirm that the motor starts in reverse. Once we know it CAN be reversed I'm sure someone can give you a wiring diagram if you can't figure it out for yourself.

                  The run winding will switch straight through while the starting winding leads need to "X" over each other from one switch to the other.
                  Chilliwack BC, Canada


                  • #10
                    BCRider, sch, I believe you are correct and thanks for the direction. But first the sad news: While being visited by my ex mechanical engineer neighbor (third time that day) and a bit frustration I cleaned up that flyweight switch and secure the Bakelite contact plate and reassemble it. Then I connected the black wires to the motor connecting block and removed the two red wires out of the circuit. With the neutral wire from the supply connected to the one black wire on the motor, I dangerously just touched or tapped the incoming live wire to the other side of the black wire on the motor – This means I am only ‘powering-up’ the black circuit in the motor through the capacitor.
                    1. The moment I hit the red incoming live to the motor black it made a humming sound and slowly turned Forward and I supported the motor by turning the pully by hand and it ran slowly.
                    2. Then in swapped the incoming red and black wires, the same humming sound, and the motor turned in Reverse!!!
                    3. The motor turned slow to such an extent that the flyweight switch did not engage??
                    4. BUT THEN: Stupid as a human can be, I swapped the wires back again and I asked my neighbor friend to turn the pully in Reverse and the motor turned nicely for 5 seconds and then the capacitor exploded.
                    What did I learn?
                    1. Never to be such a fool in pushing your luck with electricity.
                    2. The black wires must have a winding (starter winding?) through the capacitor.
                    3. The red wires in the motor are connected to the main winding.
                    4. To set the motor in Reverse and Forward the two black wires should be changed.
                    What I don’t know yet:
                    What is the function of the flyweight switch?

                    I checked all windings afterwards and it seems that they are still intact and just need to get a 200 micro Farad capacitor on Monday and be careful this time.

                    What is your take on this tragedy?


                    • #11
                      The starting winding with the capacitor is not intended to run the motor or to be powered for more than a couple of seconds. That's why it runs through that flyweight operated switch. The starting windings on such motors are only intended to kick the motor. If you run it with just the red windings it'll start in either direction or just sit and hum until you kick the pulley one way or the other. Then it should spin up to full speed. The starting winding acts like that flick on the pulley to get it to go the desired direction. But the starting winding isn't intended to actually run the motor like you tried to do. And the electrical "load" that produced is likely what blew up the capacitor.

                      This is why all our posts to check things involved keeping both windings connected but just flipping the wires on the one winding only.

                      The good news is that motor capacitors are not that hard to get. Any decent industrial electrical supplier should have them. But they do come in different values of capacitance. You'll want to find the printed or stamped values on the casing and take that along to show the guy what you want.
                      Chilliwack BC, Canada


                      • #12
                        BCRider, you are correct and I believe I am a 'slow learner'. Worked with these things more than 18 years ago! Just before I changed the wires that blew the capacitor I heard a 'voice' saying "don't do it!" but you know how it goes in life.
                        Will get the capacitor on Monday, reconnect 'slowleyyyyy' and let you know.



                        • #13
                          We all have those "brain fart" moments. You're in fine company....

                          In the meantime we can help you out with that switch unit. But before we can suggest a wiring diagram we'll need to confirm or debunk what I think is the case. Namely that there's a latching system in the upper portion of the box with the buttons. When you push on the FWD button a finger latches down and pushes down on one of the center bars for the contact units. And when you hit the red STOP button that lets the finger snap away. And same for the REV button that latches down a second finger to push on the other center bar of the other contact unit. Is that the case here? If it is I'm pretty sure we can fix you up to get the motor running with a FWD and REV function.
                          Chilliwack BC, Canada


                          • #14
                            BCRider, You are correct and I am attaching pictures of the switch as been reassembled and I thought ‘ready to go’.

                            The top side of the switch is the buttons cover with a ‘latch system’ Off, Left or Right. When Left or Right is pressed it pushes downwards onto the contactors side and engages the contactors and ‘click/hook’ onto a small notch one a small plate until released by the centre Red pin.

                            The bottom side of the switch consists of two independent spring-loaded contactor sets (Bakelite) and each set allows 3 loads/wires/phases to be used where the ‘incoming’ currents can be sent through to the other side of the corresponding contactors when a left or right button has been pushed. The Red centre button has nothing to do with the bottom switch.

                            The centre Reb button pushes the Forward and Reverse latches (spring-loaded) to all OFF positions. The switch may then be pushed For or Rev. Seems the Red button causes the electrical circuit in the motor to be zero. Safety?

                            Am I correct to say that each set of contactors should have a Red live and Black neutral wire, but the black wires should be ‘changed’ or should the ‘change’ happen or the box at the motor?

                            You may only view thumbnails in this gallery. This gallery has 5 photos.


                            • #15
                              Something like this should work, Brown live and blue neutral incoming on the left, red and black windings on the right, two contact sets:
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                              And PLEASE fit nice safe cable glands where they enter the switch box, and make good earth connections at both the box and the motor!

                              Be aware, if you're on US 220v (two hot wires, no neutral used) the motor WILL have 110v on it permanently, but no return path to spin it in the "off" position...Isolate supply before working on it!

                              Dave H. (the other one)
                              Rules are for the obedience of fools, and the guidance of wise men.

                              Holbrook Model C Number 13 lathe, Testa 2U universal mill, bikes and tools