davedj1
Veteran Member
There is an electric governor available too. I would go that route. I don't think fan speed will be that critical once it's up and running. Just like any other hydraulic run machine, pump will vary with engine rpm.
Rexroth does offer a control for their closed loop pumps that offers automatic transmission type drive where the pump will never stall the engine. It adjusts the pumps displacement based on engine RPM. I don't know if any other companies offer this type of mechanical control.
The more complicated you make this system the more stuff to go wrong.
Since this is the hydraulic forum, I will assume you are going to use a hyd motor to run your blower fan. If this is so, you can use a variable flow control to control fan speed. Set your engine rpms with a throttle stop. You can also get a throttle cable with a knob you just twist to adjust engine speed. It will push in for shut down and pull out for WOT and just twist the knob to adjust anywhere inbetween.
I guess I don't understand why you want to re-engineer something that already exists??? A snowblower mounted on a truck or tractor, powered by either the vehicle's engine or a separate dedicated engine for the blower already exists.
Is this just a fun thing to do? If so, I'm with ya! :thumbsup:
If not, I can't sit around and watch someone poke themselves in the eye with a sharp stick.
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I learned that from the current rig with an electrical control system, now THAT's a bonafide nigghtmarte!
That rexrot idea is interesting. Mine came from airplane constant-speed props, similar idea.
under that scenario i could use a controllable governor on the engine, set the engine rpm to ballpark what i need. That would pour some more coal on when tending to stall (and THAT does happen a lot). A volume control could be driven by a governor on the fan, that governor i could set for the fan speed i want. This is roughly what i'd be looking for, it's just that i've never done anything like it.
Maybe I am missing something but why bother to vary the blower speed at all? Why not vary the travel speed to match the loading? Having the blower turn fast with a light load would be much more efficient than using variable speed hydraulic pumps, motors and their controls.
For Rexroth do a search for RE92003. That is the data sheet for the Rexroth A4VG closed loop pump. The control you are looking for is called "DA" This data
sheet explains it much better than I can.
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