At 02:44 AM 2/6/2013, Dick Wong wrote: >With my old Scirocco, the fuel pump relay will get hot to the touch and has >actually melted the side of the plastic case. After filing and cleaning the >contact, it typically runs cooler. I also keep a spare fuel pump relay. Dick, we used to use a "point file" on ignition contact points to get rid of the "mountain" deposited on one side by the arc, but those points are made of tungsten. Relay contacts are typically silver and may or may not be a thick solid piece of same -- either way they're very soft. Rather than a file I'd suggest using 1500-grit or even finer wet-or-dry paper to do the cleanup. I'd also suggest tracking down why it's running hot. Bad contact in the socket maybe? A relay should not run hot unless something is wrong. If the contacts are pitting rapidly because it's switching an inductive load, try adding an old-style ignition condenser from the load side to ground, or put a reverse-polarized 4004 diode across the supply and load terminals. If the diode fails, use a higher voltage rating. I think a 4007 has a 1,000 V PIV (peak inverse voltage) rating, which ought to be enough. 4004 IIRC is 200 V. 4001 is 50 V, probably not enough. In general terms, a one-amp or better power diode with PIV at least 200 or 400 volts should do. Hook up with the marked end facing the supply. If the marking is an arrow pointing to a bar, hook the bar side to the supply. Yours, David |
Please note - During the past 17 years of operation, several gigabytes of
Vanagon mail messages have been archived. Searching the entire collection
will take up to five minutes to complete. Please be patient!
Return to the archives @ gerry.vanagon.com
The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.
Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.