On Sun, 29 Nov 2009 02:05:53 -0500, "Existential Angst"
wrote:

"Karl Townsend" wrote in message
tanews.com...
I need a second portable air compressor to haul out into the orchard. So I
bought a 13 hp yanmar diesel. I have a nice Quincy 2 stage air compressor
made to run on an electric motor a sittin' on the shelf.

Do they make/sell change parts to run an air pump on a small engine? it
must be simple but I'm not sure what is needed.

How bout having the diesel turn a generator head, to drive the compressor
motor ?
If the diesel itself is electric start, you could rig it up so that when the
pressure switch calls for air, it starts the diesel, so the diesel doesn't
have to run all the time.

Far too much conversion loss, and way too RUbe Goldberg. (NOT That
there's necessarily anything wrong with that...) You turn gasoline or
diesel fuel into rotational energy at a loss (thermal mostly), then
convert the rotational energy into electricity at a loss, then the
electricty BACK into rotational energy at a loss, just to turn the
compresor head.

If you have the engine running, you turn the compressor head direct
to the engine and cut out all the other conversion losses - the only
reason to be running an electric compressor is when you don't want to
run the prime mover yourself, you buy the energy off the grid.

The smart way is to get the Constant Run Unloader assembly from
Quincy, which will involve a special head with pistons to hold the
intake valves open to eliminate pumping losses. And a second air
cylinder that drops the engine back to idle when the head is unloaded.

And if there is ever a call for electricity out in the field, say to
run a Sawzall for pruning, or flood lights for that 2 AM repair work,
you get a small belt-drive alternator head (1 KW to 5 KW) and belt it
in parallel with the compressor. (And delete or bypass the idle
control when you want power and air at the same time.)

They sell these commercially, search for "air and power" combo.

-- Bruce --