I have two pieces of equipment in my shop with magnetic switches and they have both gone bad. I opened up the case for the band saw switch, and after some fiddling, discovered that the contacts between two of the parts had gone bad. I cleaned them and it ran fine for about a year and now it is bad again. Upon doing the same for my Jet table saw, I went further and opened the case (big mistake). These switches are made up of many tiny levers and springs that I have no idea how to get back together even if my fingers could control such tiny objects.
My question is, is this common? Does anyone have any idea why they would go bad? They are not 100% sealed, but they do not seem too dusty inside either. I am really confused and i do not want to have to replace them, but I am wondering if there are things I should be doing to protect them or what
Thanks
Joby
Replies
Let's put it this way. It's not un-common. Switches can go bad for a number of reasons. The most common is wear. Even if a switch box is sealed the contacts wear against each other. I would replace them rather than try to fix them. Grizzly has a good selection of magnetic switches.
Len
"You cannot antagonize and influence at the same time. " J. S. Knox
I agree with Len. I had one go bad and looked around locally. It was going to be $80 to $100 for a replacement. Called Grizzly and $20 later I had a new switch. It works fine.
Bob T.
It is common. More common with el cheapo type switches that are often found on "home use " machines, especially single phase stuff.
Every time you fire up there is chemical and mechanical erosion on the contacts because of arcing, especially if the switch is near capacity and heavily loaded. Dust is an aggravating factor as well.
You can prolong the life of these things by regular dust removal and ensuring that that all terminal connections are tight. You can use aerosol switch cleaner fluids and intelligent compressed air. Some contacts are not meant to be "cleaned" by use of abrasive papers, so if in doubt don't use- just scrape with a sliver of wood or cloth and use switch cleaner.
If you pull them apart it is best done on a good day on a suitable work surface. Springs and small screws always run and hide.
High humidity is also a possible cause for them to go prematurely bad.
David Ring
http://www.touchwood.co.il/?id=1&lang=e
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