The Rishabh Reverse Power Protector provides continuous surveillance for a.c. generators operating in parallel or for boosting mains supplies. On site adjustment of the trip point and time delay ensures accurate protection against ‘motoring’ in the event of engine failure and prevents tripping from surges during synchronising.
Principle of operation :
The generator voltage provides the power supply for the relay energising circuit and phase reference for the phase sensitive detector. Current reference to the detector is taken from the generator load current. The output from the detector is compared with a reference which is set by the trip set point potentiometer. When the set point value is exceeded an electronic trip operates to energise the relay circuit through an adjustable time delay.
Setting up Instructions :
The ”% set” potentiometer trimmer on the front label is calibrated as a percentage of the input current rating e.g. Of 5A, and not of the forward kW. Adjust the “% set” trimmer to the required tripping value, 7.5% to 10% is normal. Setting accuracy can be checked by reversing the current lead connections and, with forward power, measuring the trip point value on a suitable ammeter (reconnect leads on completion). Units with built-in test switch simplify this operation. Adjust the ‘Delay’ to the required time delay. 10 seconds is normally adequate.
