Need Help with Hegner Polymax On/Off Switches

[Izzy Charo]

Hello,
I just acquired a 1985 Hegner Polymax 3 Scroll Saw... (Hegner saw #4242). I believe this is a high-quality saw, but it needs some work. It runs, but the On/Off switch assembly is falling apart. Advanced Machineries, the U.S. dealer for Hegner, is not sure there is a part number for the individual button switches...and I don't want to buy an entire new switch/card/box assembly just to replace the button switch. I'm hoping someone can help me figure out a replacement for these two switches, which have only two wires going to each. I'm not sure if they are "momentary" switches, or if there is anything special about them .... the motor is 3.6A, 110V, if that helps..
Thanks very much,
Izzy

[Lisa Starr]

They appear to just be panel switches which are readily available. Figure out the specifics of the switches (voltage, push, turn etc) and then take a look in McMaster Carr. They offer lots of explantion to help you sort it all out.

[Robert Hayward]

I have a Hegner just a couple years newer. Mine has a rotary knob for the variable speed and an on/off rocker switch. The control box on mine looks very different than yours though.

Is yours variable speed? If so I can take the cover off my box and give you the specs of the rheostat. You control box is labeled 1/0 though which tells me it is on/off and not variable.

[Izzy Charo]

The Polymax model is not variable speed...on/off switch and belt drive. Thanks.

[Stan Coryell]

Is there a manufacturer's name or part number on either switch? Can you check continuity to see if the switches are Normally Closed or Normally Open? They may be different. Are they momentary or maintained? Measure the hole size, in millimeters.
I'm sure you can find something to work. Do you have a skematic? That may also be helpful.
I don't have any experience with your machine, only controls.

[Stan Coryell]

McMaster-Carr Page:
https://www.mcmaster.com/Momentary-Switches/plastic-22-mm-panel-mount-push-button-switches/actuator-style~push-button/push-button-style~flush/

[Bill Dufour]

Do they switch the power or are they pilot switches that control a relay? If they are pilot the on switch is No and the stop is NC.
Bill D

[Izzy Charo]

I don't know how the switches are set-up because I just acquired the saw and the switches appear non-functional. I did find a schematic left by the previous owner (who has passed away), and it's noted that he "hot-wired" it for use with a foot switch. The schematic is shown below...afraid a bit too complex for me, but perhaps decipherable for others to determine which type of button switch they used... Thanks again for the help!

[Bill Dufour]

That is a standard contactor type switch the switches do not carry much power. they switch a relay which has heavy contact points that carry the load. In the bottom left of the diagram are the control switches.
AUS is the stop switch. It is normally closed.
EIN is the start switch. It is normally open.
These are both momentary contact switches.
Measure the diameter of the threads that mount it to the panel. That is the only critical measurement. I believe they switch 120 volts.
Bill D

I believe A1 and A2 are the coil connections.
L1 and L2 are power in
U1 and U2 are power out to the motor.
I have no idea what Z1 and Z2 are, maybe a heating coil?

[Stan Coryell]

I don't know what language it's in, but it's a magnetic contactor without thermal protection.
EIN = Start (NO)
AUS= Stop (NC)
13 & 14 = auxiliary NO

It looks like you have to put power, L1 and Neutral, back on 2 & 4. The contactor appears to be bypassed for the foot switch.

A picture of what the wiring looks like would be helpful.

Test the STOP switch for continuity. It should have continuity normally (Normally Closed), pressing it should break continuity.

Test the START switch. It should not have continuity until pressed (Normal Open)

[Stan Coryell]

Bill types faster!

U1 & U2 are motor Run winding connections
Z1 & Z2 are motor Start winding connections

[Izzy Charo]

Thanks for the detailed information! Very, very helpful! I have spent a fair amount of time on the McMaster Carr website looking at momentary button switches and I have a couple more question before ordering... By way of background, the saw is set up so that it goes on spontaneously when plugged in,,,no need to push any switches (which as I said disintegrated when I did press one when it was unplugged). It was operated by a foot pedal, which I assume the power cord was plugged into. So, knowing that, do I order TWO switches that are Normally Open (NO)...or one Normally Open and one that is Normally Closed? And do I need momentary switches that Remain On after pressing them? Here is what I've been looking at on McMaster Carr: but they do not say that switch remains open/closed... Thanks for all the help!! Izzy
https://sawmillcreek.org/webkit-fake-url://632a3c69-de53-4882-83d8-5dd67010b60f/image.tiff

[Izzy Charo]

Sorry... link to McMaster Carr did not seem to come through:

https://www.mcmaster.com/momentary-switches/actuator-style~push-button/for-panel-cutout-diameter~16-mm/

but they do not say that switch remains open/closed... Thanks for all the help!! Izzy
https://sawmillcreek.org/webkit-fake-url://632a3c69-de53-4882-83d8-5dd67010b60f/image.tiff

[Stan Coryell]

Start- Momentary, Single Pole, N.O.
Stop- Momentary, Single Pole, N.C.

ANY momentary switchs may be used, as long as you have one NO and one NC.

Your only limits are 120VAC and physical size.

Don't forget to move Black and White, L1 & N, back to where they belong on the contactor.

I'l send a McMaster link for 22mm.

Are you using their App?

[Stan Coryell]

Start Buttons, Flush Push-Button, Push Reset, 1-3/16" Diameter, SPST-NO

https://www.mcmaster.com/6749K101

This may work for Start.

[Izzy Charo]

Stan... once again, Many Thanks! I'm afraid I was confusing...I have the foot pedal and plan on using it. So, in that case I assume I wouldn't need to change the wiring? I'm using the McMaster Carr website, which I think is pretty good... the holes in the panel are 16mm, but I suppose I could drill them out to 22mm if need be. Hope this helps...

[Stan Coryell]

If you leave the wiring the way it is, you don't need the start/ stop station and can't use the contactor.

If you want start/ stop, the foot pedal needs to be wired parallel to start. To do this the wiring must be restored to the schematic you posted.

McMaster does have 16mm push buttons.

[Stan Coryell]

Apologies, I posted a photo too quickly.

To use a foot switch with the contactor, you need double pole/ double throw (DPDT). The Stop circuit has to open and the start circuit has to close for it to operate independently of the start/ stop station.

You are welcome.

[Izzy Charo]

After thinking this over a bit, I think the foot switch alone is the easiest solution. I'm not sure why I would need the Start/Stop panel switches if I can do Start/Stop with the foot switch alone... Appreciate all of the input. Thanks again!