Originally Posted by Jim Lane

It is a little more involved than simply spinning an alternator with your truck engine.

Both frequency and voltage are directly propionate to the RPM the rotor is turning, smaller units usually turn at either 1800 or 3600 RPM while larger units can be 1200. (determined by how many poles.)

You need to have a governor connected to the throttle to keep the rpm's constant, if not when the voltage droops so does the frequency, the governor should keep it between 57 to 63 Hz any higher and the voltage will creep up around 140 volts and things will start burning out on you.

Induction motors (blower motors, sump pumps, well pumps) that rely on the 60hz line frequency to synchronize will now try to turn faster and overheat if the RPM's are not correct.

I have and work on Onan CCK gensets used in RV's as well as I used to own a Mep-003a Military Genset powered by a 4-cylinder air cooled diesel engine, producing 10kw both single AND 3-phase power, weighing almost 1300 pounds.

There are 2 ways I can think of to approach this problem.
With the generator head directly connected to the transmission through the PTO shaft, choose the final drive to be close to the needed output RPM, install a Woodward Governor on the front of the engine connected using a belt, have a quick connect ball and socket connecting the governor arm to the VE throttle shaft.

In generator mode you would need to connect the governor to the VE, when you start the engine the governor would keep the engine at 1800 RPM rock solid, you would need to disconnect the governor to drive the truck.

Originally Posted by j_martin

If it were me, I'd get one of those PTO driven things, find a PTO and maybe a gear box or multi V belt drive to spin it at the right speed. I'd probably figure an engine speed around 1200 rpm. No need to wind it out for 30 hp or so. I'd molest the cruise control, either spoofing speed data to the PCU, or driving the vacuum control solenoids with a custom speed regulator circuit. I'd switch the wiring between them with a miniature multi pole relay called a cradle relay. Very reliable for small currents.

Originally Posted by taterfarm

I think pickup and tractor governors are different so a hand throttle wouldnt keep it steady if the load changes. I have heard that there are problems when someone swaps a truck pump onto a tractor for that same reason. Although the load is so small compared to engine power that it probably wouldnt make much difference if the generator can account for it.

I do agree that 1200 rpms would be a good place to be and should be quite steady with the torque ratings we have.


Jim, I like those hydraulic units, never heard of that before. Any idea on rough cost?

Originally Posted by JD730

Jim,
Why would you need to connect another governor to the VE? The VE's in our trucks have their own internal variable speed governor, if a tractor running a PTO generator can handle it I would think one of our truck engines should be able to handle that. A simple hand throttle is all that would be needed, then simply run the rpm's up till the Hz and voltage are right.


I would avoid using the cruise control at all costs. A simple hand throttle would work best, the VE has its own variable speed governor and should be more than capable of maintaining RPM like a tractor running a PTO generator would.

Originally Posted by kiszka6911

On a Military CCUV M1031 K30 pickup they drove a bed mounted 12KW generator from a PTO monted shaft. Google M1031 PTO generator, you will find lots of pictures. A muncie PTO was used.

Originally Posted by Jim Lane

The internal governor in out VE controls the maximum speed of the engine by defueling, the governor used on generators detects engine speed either mechanically or electronically through a pickup in the flywheel housing, a lever connected to the throttle keeps the engine at the set speed.