DC Fan Sensors

Three types of DC fan sensors are available: Locked Rotor Signal; Tachometer Signal; and Life Signal. The Lock Signal, which outputs the status of the fan motor, is ideal for detecting if the fan motor is rotating or is stopped. The Tachometer signal is set to produce two cycles of rectangular waveform as the fan motor makes one rotation, thus providing an ideal sensor for detecting speed. The Life signal  is ideal for detecting a reduction in fan speed at a specified RPM level.
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 Output Circuit/Alarm Signal Circuit  Lock Signal  Tachometer Signal