I have microswitches on my blast gate doors that turn the DC on through a relay. Occasionally one will stop working, sometimes won't turn the system off and sometimes won't turn it on. I have found that if I wiggle the wires or at worst take it off and flick it on and off and wiggle the wires/connectors, it goes back to work. I have spares, but have never actually installed one.
Any idea what's going on? I'm guessing sawdust in the contacts.
Could be dust but as a rule most of them are sealed pretty well. Maybe they are just a bit flakey. Since it also affects the turning off, it sounds like the actuating mechanism inside isn't moving the contacts properly - unlikely they are get welded shut since your control is likely low power.
Yes, sounds like sawdust is your problem. These type of switches are generally very inexpensive. Replace it. Then, if you're like me, drill out the rivets on the bad switch, clean it out and reassemble using machine screws to replace the rivets. Then, you will have a spare.
The switch on my Performax got glitchy, so I replaced it. Then I took the old one apart and found it was completely stuffed with sawdust. I tried to put it back together, but I did not have enough fingers and toes. You got to ask yourself, Self, who designs a switch for a sanding machine that is not sealed and then mounts it looking straight up? Wonder why they did not just put a funnel right over it?
I've repaired many switches over the years instead of buying new. The worst offender is fine dust, wood or otherwise. Moisture is next. I disassemble, clean, clean and if needed polish the contacts and coat with a tiny amount of dielectric grease, reassemble and seal the switch by some means from future dust intrusion.
I built my blast gates and used magnetic activated "reed switches" to trigger the relay to turn on and off my cyclone. Reed switched are completely encapsulated switch mechanisms that are used in home security systems - they're the switches that are installed in window and door casings that trigger the alarum when the window or door is opened while the system is armed. They are weather-proof and completely sealed against dust and moisture. I used small rare earth magnets in my blast gates to activate them. Here his a photo:
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The reed switch in the photo is the little round white spot on the blast gate frame (below). A complete copy is laid on top. The switch is a pressed friction fit into a pre-drilled hole in the plywood rotor. The little round circle in the rotor of the blast gate (above) is the magnet. It lines up with the reed switch and activates it when I rotate the rotor to the open position. They've been in place for 5 years or more, used heavily. I've never had a failure. There's not much about them to fail. I can find the brand I used if you're interested, but they're common so you can Google reed switch and find lots of examples. The best part is that they're inexpensive compared to microswitches.
In case my photo doesn't make sense, here's another of the blast gate installed:
Reed switches are great! (no way dust will get into these) I still have a bunch of tiny ones from 30 years ago. The ones I have are tiny glass capsules with a 1/4" solid wire extending out each end. With a strong magnifier you can watch the contacts inside move in a magnetic field. A friend and I embedded these in a variety of things for sensing position.
Thanks for the suggestion and the design. My blast gates are store bought, Long Ranger I believe. I would have used your design if I had known of it. Mine have been in use for about ten years and worked well about 99% of the time and "fixing" them usually takes a minute or two and is more of a distraction than a problem. I fiddle with them and they go back to work usually for months. I have spares and all I have to do is threaten to replace one and it goes back to work.
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