how to test a forward and reverse motor circuit

Bi-directional hydraulic motor at rest with pump running.įig. Maximum pressure allowed (in psi, arbitrarily decided by the engineer or designer) Fig.

How motor will be stopped (coast, braked, decelerated, other)Ĥ. Maximum speed required (usually in revolutions per minute, rpm)ģ. Maximum torque required (usually in in.- or ft-lb)Ģ.

To size a hydraulic motor system, the following information must be known:ġ. Figure 12-3 shows a variable-displacement bi-directional hydraulic motor symbol. Figures 12-2, 12-3, and 12-5 show motors designed for bi-directional operation. Variable-displacement, bi-directional hydraulic motor.įigure 12-1 and Figure 12-4 show the symbols for a uni-directional hydraulic and air motor. To stop and hold over-running loads, use a brake or other external device. Unlike cylinders with resilient seals, hydraulic motors always leak or bypass internally. They also operate safely in most environments and save space at the work site. With proper valving they produce little shock, and their efficiency is in the 80 to 95% range. Hydraulic motors, on the other hand, can produce speeds from 1 to 5000 rpm. Without a good silencer or muffler, air motors are loud. Power level and torque also vary widely with speed change. Uni-directional hydraulic motor.Īir motor speed varies with load changes. Minimizing run time by starting and stopping the motor helps offset low efficiency in many applications. Air motor efficiency is very low - only in the 15 to 30% range. A less expensive, more-compact gerotor-design air motor that operates in the lower-speed range also is available.Īir motors operate safely in most environments and save space at the work site.

Piston-type motors are larger and more expensive, but they produce high torque at low speeds. For some high-torque applications, vane motors with integral gear reducers work well. Vane-design air motors are common in low-torque/high-speed applications. Make allowance for this reduced torque if the motor must start under load. However, remember that fluid motors have approximately 50% less starting torque than electric motors of the same horsepower. To size a fluid motor, calculate torque instead of horsepower. These features - along with compact size - make fluid motors the best choice in many applications. Also, hydraulic motors commonly operate at low speed without a gear reducer. Repeated starting and stopping air or hydraulic motors does not cause damage or overheating. Changing motor speed (within the limits of its specifications) does not adversely affect torque. These fluid motors produce rotary power that can drive conveyors, operate long transfers, power fan blades, run a winch, drill and tap a hole, and handle many other applications.Ĭompared to electric motors, quick reversal of rotation or stalling does not damage a fluid motor. One way to change fluid energy into useful work is through air or hydraulic motors.

How to test a forward and reverse motor circuit