Hydraulic motors are found in any app requiring rotational force, also called torque. A hydraulic engine converts hydrostatic energy into mechanical energy by pressing vanes, gears or pistons attached to a crankshaft.
Hydraulic motors are used for most applications now such as winches and crane 
drives, wheel motors for military vehicles, self-driven cranes, excavators, conveyor and feeder drives, cooling fan drives, mixer and agitator drives, roll mills, drum drives for digesters, trommels and kilns, shredders, drilling rigs, trench
Hydraulic motors are rotary actuators that convert hydraulic, or liquid energy into mechanical power. They work 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 continuous input stream is provided.