A Zero - Speed Pulse Tachometer

This paper describes a new pulse tachometer system which combines the environmental virtues of the reluctance pickup with an independence from speed generally associated with more complex and fragile types. The mechanical properties of the sensing head permit considerable freedom in the manner of its installation; in the application described it is mounted in the end-bell of a self-ventilated traction motor. Electrically, the system can produce pulse rates from zero to at least seven kilo-hertz with a purely digital (square wave) output, can tolerate fairly long cable connections between the remote sensing head and the electronics, and is compatible with digital control schemes.