View Single Post
Old 01-20-2011, 05:16 AM   #3
BB_TX
Montana Master
 
Join Date: Oct 2006
Location: McKinney
Posts: 7,172
M.O.C. #6433
Quote:
quote:Originally posted by illapah

I wonder if a capacitor in parallel would be of any help???
Not for this problem.
With AC current, the current flow actually stops for an instant 120 times every second (each half cycle) as it reverses flow. So AC current across a contact will stop much easier without arcing so much.
But DC current is continuous. When the contact opens, the current will continue to flow across the gap (arcing) until the distance is too great for it to continue. That arcing burns the contact a little each time. And each burn increases resistance across the contact causing a little more heating the next time.
For high voltage (125 VDC) and high current applications at my old job, we used special relays with magnetic blowout to suppress the arcing problem. A bit expensive for this simple application.
__________________
Bill & Patricia
Riley, our Golden
2007 3075RL (recently sold, currently without)
BB_TX is offline   Reply With Quote