Questions about gas engine air compressors

[Mandres]

So I recently came into posession of a good 5hp Briggs motor and I was thinking about piecing together a portable compressor. I have a line on a tank and pumps are easy enough to find. I'm wondering how the pressure switch works on non-electic compressors. How does the switch trigger the motor to rev up? When the tank is fully pressurized does the motor just idle? How is the idleing motor unlinked from the pump (some kind of centrifugal clutch?)

Thanks

 

[Charles (in GA)]

General rule of thumb, for whatever horsepower it takes to run a pump with an electric motor.......... double that for a gas engine.

Basically you cannot make much of a compressor with a 5hp engine.

Charles

 

[Morrisman]

So I recently came into posession of a good 5hp Briggs motor and I was thinking about piecing together a portable compressor. I have a line on a tank and pumps are easy enough to find. I'm wondering how the pressure switch works on non-electic compressors. How does the switch trigger the motor to rev up? When the tank is fully pressurized does the motor just idle? How is the idleing motor unlinked from the pump (some kind of centrifugal clutch?)

Thanks

I have a vague recollection that a bleed valve unloads at the correct pressure setting, letting the air escape 'overboard' until the pressure drops sufficiently, then it shuts the unloader (overboard valve) and puts the air directly into the reservoir. The engine runs continually, and drops to idle when it is 'unloaded' but it will rev as it loaded up the compressor again. I believe there is some sort of governor that senses engine load and opens/closes the throttle to maintain speed at whatever load is required.

This all stuff I remember from years ago, so it is probably done with 'puters nowadays.