The Electronic Speed Monitor Relays EDO/JMNC are 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
opto-electronic pulse transducers 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
setpoint. The output relay contacts of JMNC are goldplated 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.