The Electronic Speed Monitor relays JMNC is used in connection with a pulse sensor to monitor the rotational speed and standstill of drives. Pulse sensors according to NAMUR-EN 50227 as well as npn pulse transducers (Kiepe model EOG) can be connected to the speed monitor relay.
The pulse output is fed to the speed monitor relay where the pulse frequency is compared with the frequency set by the control of the relay. When the input frequency passes the set frequency the internal output relay is switched.
Warning or control equipment can be connected to this output relay and operate when the speed either increases or decreases from the set point. The output relay contacts of JMNC are gold plated to improve true contact even in case of low voltage circuit operations.
The operation of the relay can be inhibited during start-up of the monitored drive by adjusting the start-up potentiometer to the time taken for the drive to reach operating speed.