Re: Help received

[<hofs@domain.elided>]

>Date: Wed, 4 Mar 98 14:56:50 -0800
>From: <hofs@domain.elided>
>Subject: Re: I need some help
>
>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. 

John L. answered this problem for me as though he had been researching it 
for a month. He gave me part numbers for Square D pressure switches that 
have a reverse operating mode. This unit will replace the pressure switch 
on the compressor. A really cool solution. Thanks John.
John

John Hofstetter  "Ol'Saline's Web Site" www.goldrush.com/~hofs
Founder of DARK  "DRIVERS AGAINST RIDICULOUS KRAP"
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Asc.
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Owner of 79 Scout Terra "It's a legend"