"Alan the Tech" wrote in message
...

A diamond file may be ok for what you do, but when I say hi current
I'm talking 12 to 16 power modules with 2200 amps coming from each
into a common buss line. with a combined current of 26400 to 35200
amps. Start taking material off the contacts and your talking some
real fireworks if you don't weld everything together. And at that
current levels a few mills of oxidation acts like a power resistor and
it gets real hot. I had a 3 inch X 5 inch X 1/2 inch thick contact
plate with just a little corrosion get hot enough to burn my hand. (I
got first degree burns that time) That was before I started to polish
the contacts.

No argument there. I'm cleaning relay contacts - max 5 amps usually and
maybe a lot less. I installed a 400 amp 400 volt busbar system once and I
did that with a wrench and a heavy hand. Expensive stuff to have burn up on
you.

N