No Start Compressor

[ToyMeKaNeK]

I have a small 40 gal Snap On compressor. It's not used all that much, but never given any problems.
Today, I went to switch it on, and nothing. Check CB, good.

I unplugged it, pulled the cover off the switch box, plugged it in and measured voltage to the switch. 243V
Then I notice when the switch is turned on, there are dual contacts that throw together.
One of them was stuck and wouldn't return when switched off. I unstuck it, and all's back to normal.

What caused this, and how can I prevent it from happening again?

 

[ibedayank]

I would replace the switch ..

 

[84scrambler]

Its just normal wear and tear for switch contacts. Your electric motor is switched on and off by those contacts. If you look at a switch in slow motion as it closes an arc will form (plasma) just before the contacts touch. This arc that forms causes localized melting and eventually failure of the contact surface. If there is enough material you may be able to clean up the contact surface (filing and polishing) but it would be easier to just replace the switch.