To control the speed of a prime mover, speed controls compare actual speed to desired, or set, speed. The speed sensor most often used to detect prime mover speed is the magnetic pickup (MPU). When a magnetic material (usually a gear tooth driven by the prime mover) passes through the magnetic field at the end of the magnetic pickup, a voltage is developed. The frequency of this voltage is translated by the speed control into a signal which accurately depicts the speed of the prime mover.
1. Produces electrical frequency
2. Easily installed on engine
3. Requires no energizing circuit from control
4. Used with all electronic controls
5. Available for hazardous location installation
