Pneumatic actuator Pneumatic actuator A pneumatic control valve actuator converts energy (typically in the form of compressed air) into mechanical motion. The motion can be rotary or linear, depending on the type of actuator. A Pneumatic actuator mainly consists of a piston or a diaphragm which develops the motive power. It keeps the air in the upper portion of the cylinder, allowing air pressure to force the diaphragm or piston to move the valve stem or rotate the valve control element. Valves require little pressure to operate and usually double or "triple" the input force. The larger the size of the piston,
Traction motor A traction motor geared for freight use with a low gear ratio will safely produce higher torque at the wheels for a longer period at the same current level because the lower gears give the motor more mechanical advantage. In diesel-electric and gas turbine-electric locomotives, the horsepower rating of the traction motors is usually around 81% that of the prime mover. This assumes that the electrical generator converts 90% of the engine's output into electrical energy and the traction motors convert 90% of this electrical energy back into mechanical energy. Calculation: 0.9 × 0.9 = 0.81 Individual traction motor ratings