Motor switch help for old Minimax combo machine

Re: Motor switch help for old Minimax combo machin

John McGaw

That sounds very much like the switch on my Meber (Laguna LT16SEC) bandsaw. Is the round portion of your switch about 2-5/8" in diameter? If it seems worth it to you I can check out the manual and possibly tear into the saw and snap some pictures to see if it really is a match. If it is, you can possibly get a replacement from Laguna.

Re: Motor switch help for old Minimax combo machin

John K Jordan

Sounds like a capacitor start induction motor where the start coil is energized through the capacitor, but those I am familiar with have a centrifugal switch that disconnects the start coil when the motor is nearly up to speed.

Perhaps yours uses the spring switch to energize the start coil, but releases manually. If so and assuming it is the switch that is bad and not the motor coil, capacitor, or other component, that single ignition-type switch might be replaced with a simple switch plus a momentary switch. I'm certainly no motor expert but I have a friend who is - I could ask him this weekend.

If you know someone with a meter and good with circuits they could probably trace things out and draw a wiring diagram. It should be easy enough to test the switch and the motor start circuit.

I have it running, but the switch won't last

Dick Coers

I was able to get the switch working well to run, but I hold my breath each time. So, there are no electrical issues, just a mechanical issue inside of the rotary switch. I was thinking the same thing John. I got a response from the Minimax owners group, and that guy spent $400 on a switch. There are 8 connections on the back of this switch, so that greatly increases the anxiety level of patching in something else. One of wire is a jumper, so that leaves 6 wires to trace. The capacitors are right there in the box, so after this keepsake box commission is finished, the tracing begins. I would appreciate you asking your friend John, thanks.

The switch is a panel mount, about 2" square, with a paddle for twisting it. I've seen those big round switches, but no idea if they have that spring back design. This thing has a wafer design on the body. They stacked different functions together, and let the internal shaft rotate all the internals in the wafers. I can post pictures if someone can use them to help.

Re: I have it running, but the switch won't last

John K Jordan

Dick, will do. Another possible option: I have repaired several switches in the past by disassembling. Sometimes contacts are burned and beyond easy fixin' but sometimes it is just cleaning and lube. I apply dielectric grease to electrical contacts to lubricate and protect from moisture and oxidation.

The better switches are put together with screws but some have tabs to pry or rivets to drill.

If disassembling, be careful - some switches have tiny spring loaded ball bearings and other things that can fall out. Also, I mark and photograph as I go. I recently disassembled an ignition switch for my little Cub Cadet farm truck and it wasn't too hard. Toggle switches can be worse.

JKJ

Re: I have it running, but the switch won't last

John McGaw

From your 2" description I started to think that it might be the same switch as on my Robland X31 multi-machine but looking just now I see that my switch only has four connections. I take it that there are absolutely no manufacturer's markings of any kind on yours? Mine is marked with a maker and part number, etc.

Re: Motor switch help for old Minimax combo machin

Matt Robinette

I have an even older Mini Max planer jointer combo and went to the USA hand of the SCM Machine Group it is the Italian holder of Mini Max. Their machines when first imported were just re-branded SCMI machines ,they had a PDF copy of my machine manual/parts but limited parts available. http://www.scmgroupna.com/us/contacts_contactse

Hope this helps

Re: I have it running, but the switch won't last

Dick Coers

I have the manufacturer and part number. Their tech guy said they have eliminated a lot of SKUs, and that was likely a custom unit back then anyway. No help from them.

Re: Motor switch help for old Minimax combo machin

Dick Coers

The odd thing about my machine is that the machine does not match the parts manual. I bought it from Eagle Machinery. I can't remember the story exactly, but recall them telling me is was the prototype, or early production sample, for the machine they would be importing. I bought it for a greatly reduced price at the time. So, I guess it's time to pay up!

I heard back from Minimax this afternoon. $379 for the switch, and they have it in stock. I told them I would need the weekend to think about it. I'll see if I can figure out the wiring schematic before making that investment!

Re: I have it running, but the switch won't last

John McGaw

Have you tried e-bay? Lots of weird unexplained stuff shows up there. Otherwise, it might be time to break out the ohmmeter and flashlight and do some tracing to find out what all of those contacts do. Somehow 8 connections, even if two of them are used for a jumper seems excessive. It might turn out that if a pair are going bad it might be possible to swap them with another (just a wild guess there).

Motor guy

John K Jordan

Dick, I talked to my motor expert buddy and he basically confirmed what I said before, for one, he would definitely take the switch apart and see if it can be fixed - the cheapest solution. Like me, he has fixed a variety of switches like that. And he repeated to watch out for spring-loaded parts!

And based on your description, he said it does sound like a induction motor with a start winding, so before forking out $400 he too would consider replacing that single switch with a pair of switches, a momentary start and a run. We both would meter each connection and trace the wiring, PREFERABLY before the switch fails! This would verify the exact function of each terminal.

While the switch is still working, I would disconnect the wires and measure continuity and resistance between all possible combinations of terminals for each position of the switch (off, run, start.). This would allow mapping the switch function without tracing and understanding the wiring schematic. (I assume this is a 220v device which would explain having so many terminals on the switch.)

Or just buy the new switch!

JKJ

Thanks John

Dick Coers

A guy replied to my post on the Minmax owners group, saying he has a wiring diagram. So that will be a big help of course! I'm leaning towards the two switch retrofit. The value of that machine is dropping all the time, so reluctant to put that big money into the switch. It ran just fine for the last few days, and I completed the keep sake box project. So urgency factor has dropped out. Thanks for all the help guys!

Re: Motor switch help for old Minimax combo machin

GolfSteve in Calgary

The failing switch sounds like a "coordinated manual control (CMC)" switch. We use these at work and they are marvelous little things. When buying one you need an electrical engineer full time for a week to specify it. You buy the switch, then you specify the contacts, and you can bolt almost an endless number of contacts onto the bottom of the switch.

Theoretically you could coordinate the start-up of a nuclear power plant with one of these by bolting enough contacts onto the bottom of the switch.

They're not cheap - probably in the price range you got from Minimax.

Check them out: http://www.senasys.com/products/cmc.php

Re: Motor switch help for old Minimax combo machin

Dick Coers

That's it Steve. Different modules snapped together with tabs and slots. Then they have this stepped and shaped shaft that rotates the internals. Mine had this little geared piece of plastic inside, that must have been a limiter. That's what fell out when I opened it. It had gear teeth on the i.d. and o.d. Yup, complicated little rascal! On the first reassembly, the rotator in one of the the last modules was hung up. That module must be the problem. A little wiggle, and alignment fix, and I got it working. No confidence it will last though.