Electronic Speed Switches
A speed switch is an electronic device that senses rotational motion and speed. The speed switch obtains a signal from a sensor device (magnetic pick-up, Mini-Gen® signal generator, alternator, or ignition coil) in the form of a frequency. This frequency is monitored electronically within the switch. When the speed or frequency reaches the desired setting or set point, the output relay tied into the control circuit is energized or switched.
Mechanical Speed Switches
A mechanical speed switch activates at an RPM specified by the user. The device is designed with a spring and weight combination to detect either underspeed or overspeed. Output is a hard contact closure specified by the user—typically SPNO (single pole normally opened), SPDT (single pole double throw) and SPNC (single pole normally closed) contacts.