How efficient is a hydraulic pump and hydraulic motor?
If the components are new, the circuit will be relatively efficient. Inefficiency will be a function of leakage in the pump and motor. The losses will go up with speed and load. The suppliers normally provide a graph that enables you to work out what the delivered power will be at a given load and speed setting. Just a quick note about the above answer, liquids are compressible but at low pressures the compression is so low it can be virtually ignored. However in applications like fuel systems, operating at around 2000 bar, diesel is compressed to be 85% of its original volume.
