Safety-relay modules consist of safety relays that are controlled by built-in monitoring functions and assure a reliable opening/closing for safety applications while providing a high level of fail-safe operation for critical processes and protection, according to Automation Direct, which has launched new speed/safety relays to provide overspeed, under speed and/or standstill detection for single- or three-phase motors. The relays monitor either external proximity sensors mounted on a rotating element of the motor/load, the frequency of the motor-power signal or the remanence voltage (back EMF) of the motor signal.
The Dold UH6932 speed monitor-relay modules have two PNP or NPN sensor inputs, two N.O. positively driven and two semiconductor-monitoring outputs.
The Dold UH6937 frequency monitoring-relay modules require no external sensors and provide two N.O. positively driven and two semiconductor outputs for monitoring. Click here to learn more.