[b]combination pump motor[/b] 1

[BobM2]

Does anyone know of a hydraulic motor that can also function as a pump? Low speeds, near 0 to 100 RPM , about 3 HP. It's for a dyno I'd like to build.

 

[jraef]

There was a PD pump made from rods moving in an eccentric chamber that would work in either direction. I saw it as a demo once but I'm not sure if it ever made it to market.

This seems like it, although I saw it in Washington State and this seems to come from Russia.

http://www.lumex.ru/eng/product/pump.html

"Venditori de oleum-vipera non vigere excordis populi"

 

[EdDanzer]

Although they will not be very efficient, any low speed high torque gerotor type motor will pump oil. If you need an efficient system a gear box to speed up the pump speed and using a piston pump is the next and most expensive choice.