Frequency Sensing Relay
This relay is a frequency monitoring relay with four stages of adjustable frequency pick up & drop out points. Each frequency set point can be set for under or over frequency operation & has an independent time delay driving an output relay. An undervoltage lockout is used to disable the four frequency outputs when the voltage falls below a preset level. Each of the four setting stages has a rate of change of frequency (ROCOF) element with an independent time delay.