Hydraulic motors are found in any app requiring rotational force, also called torque. A hydraulic electric motor converts hydrostatic energy into mechanical energy by pushing vanes, gears or pistons attached to a crankshaft.
Hydraulic motors are used for many applications now such as for example winches and crane drives, wheel motors for military vehicles, self-driven cranes, excavators, conveyor and feeder drives, cooling fan drives, mixer and agitator 
Hydraulic motors are rotary actuators that convert hydraulic, or fluid energy into mechanical power. They function in tandem with a hydraulic pump, which converts mechanical power into liquid, or hydraulic power. … Fixed-displacement motors drive a load at a continuous speed while a constant input circulation is provided.