Re: I need some help

[<hofs@domain.elided>]

Help, help, help, help
Eldon, John, Steve, and anyone else of that ilk,
My son has a new service truck (Navistar diesel, of course) and instead 
of driving the V4 air compressor (that ran off the 460 Ford engine on the 
previous truck)  off the truck engine, he is mounting it so that the gas 
powered welder in back can also run the air compressor. When the 
compressor needs to run because of reduced air pressure it closes a 
relay. (Exactly the same as our home compressors)  The welders engine 
idles when it's throttle linked solenoid is closed, and runs at normal 
rpm when the solenoid is open. So, you see, the compressor needs to 
signal the engine by denying the solenoid power rather than supplying it 
with power. The answer would seem to be to put a normally closed solenoid 
between the two. The compressor is low so its relay closes, which would 
then open the new solenoid which is normally closed, and this opening of 
the new solenoid would deny power to the engine solenoid which would 
cause the engine to speed up. 

I can't find a normally closed solenoid. Help!
There may also be some other answer that neither he nor I have thought 
of. 
John

John Hofstetter  "Ol'Saline's Web Site" www.goldrush.com/~hofs
Founder of DARK  "DRIVERS AGAINST RIDICULOUS KRAP"
Life Member, National Rifle Association     California Rifle and Pistol 
Asc.
Member, Sierra Macintosh Users Group  Member, MacTwain Macintosh Users 
Group
Charter Member, FRIENDS OF DEATH VALLEY   Member, Blue Ribbon Coalition
Life Member, Association of California School Administrators
Owner of 79 Scout Terra "It's a legend"