Cost is clearly a huge factor in any component selection, but initial price and expected existence are simply one part of this. You must also understand the motor’s efficiency rating, as this will element in whether it operates cost-effectively or not. Furthermore, a component that’s easy to 
restoration and maintain or is easily transformed out with other brands will reduce overall system costs in the end. Finally, consider the motor’s size and weight, as this will effect the size and weight of the machine or machine with which it is being used.
Hydraulic motors may use various kinds of fluids, so you must know the system’s requirements-does it need a bio-based, environmentally-friendly liquid or fire resistant one, for example. In addition, contamination could be a problem, so knowing its resistance levels is important.
You must know the utmost operating pressure, speed, and torque the motor will need to accommodate. Understanding its displacement and movement requirements within a system is equally important.
At the medium-pressure and cost range, vane motors include a housing with an eccentric bore. Vanes rotor slide in and out, operate by the eccentric bore. The movement of the pressurized fluid causes an unbalanced drive, which forces the rotor to turn in one direction.
Piston-type motors are available in a variety of different designs, including radial-, axial-, and other less common designs. Radial-piston motors feature pistons organized perpendicularly to the crankshaft’s axis. As the crankshaft rotates, the pistons are shifted linearly by the liquid pressure. Axial-piston designs feature a amount of pistons arranged in a circular pattern in the housing (cylinder block, rotor, or barrel). This housing rotates about its axis by a shaft that is aligned with the pumping pistons. Two designs of axial piston motors exist-swashplate and bent axis types. Swashplate styles feature the pistons and drive shaft in a parallel set up. In the bent axis version, the pistons are organized at an position to the main drive shaft.
Of the lesser used two designs, roller superstar motors offer lower friction, higher mechanical efficiency and higher start-up torque than gerotor designs. Furthermore, they provide smooth, low-speed operation and offer longer life with less use on the rollers. Gerotors provide continuous fluid-restricted sealing throughout their simple operation.
Specifying hydraulic motors
There are several important things to consider when choosing a hydraulic motor.