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Old 08-30-14, 11:13 PM   #8
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Originally Posted by sunspot View Post
I'm looking for examples of windmills (hawt or vawt) coupled to hydraulic pumps. If anyone has stumbled on something like this I'd appreciate a link. A direct driven air compressor pump would also be of interest.

What you're describing is a pneumatic machine. Industrial size compressors can get over 90% motor efficiency, but the kW power at shaft of pneumatic tools over kW work going into compressor is something like 10%.

I wouldn't unless you have a need for compressed air or you want to drive refrigeration cycle directly. you could put the condenser coil downstream like shown.

Another way would be hydrostatic drive. You drive a piston or gear pump with the windmill.

Many farm equipment uses this. The tractor engine drives the hydraulic pump and the lever is used to change the displacement of hydraulic motor or the pump.

You definitely need some sort of relief valve, because this is a close equivalent of chain drive and the momentum of the moving parts will smash through the drive-train and literally blow apart the weakest link if the load gets jammed. A big advantage is that you can slowly brake the hydraulic motor or throttle the valve, then valve off the hydraulic line to get a positive braking of the wind turbine when needed and leave all the heavy mechanical equipment at the bottom.

If you you need to overcome the static friction to start it, you could back-drive the hydraulic motor with a starter motor or something to get it going.

On the output end, do as you will with any PTO shaft. With the control lever, you have a CVT at your disposal.

A doubly fed induction machine makes a good power generation source while avoiding the use of failure prone full-conversion power electronics.

It would be a good idea to use some type of biodegradable hydraulic fluid, because if you have a spill, it reduces environmental liability.
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Last edited by ICanHas; 08-30-14 at 11:22 PM..
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