• Prok Devices Private Limited

Earth Leakage Relay

Prok Devices offers earth leakage relay (ELR), a protective device which detects earth leakage currents in an electrical system. This protects electrical power system from damage, fire hazard, etc. To detect earth leakages, the sensing device used is the core balance current transformer (CBCT). Under healthy conditions the output across CBCT is zero. Under fault condition an output across CBCT develops a low level AC signal which is rectified and fed to a voltage comparator. When this signal exceeds a preset level, the comparator output changes and operates a relay through a relay driving circuitry. The miniature relay in turn alarms/energizes the trip circuit, ie, shunt trip or UV coil, thus isolating the fault by tripping the MCCB/OCB/ACB contactor. The sensitivity of the relay is use selectable by a potentiometer. A green LED glows when the system is healthy, and red one under leakage/fault condition. The relay has external test and reset facility to ensure safe unit working condition. The sensitivity of the relay ranges from 4-12 amps, 1-8 amps, 1-4 amps, 0.5-2 amps, 300-3,000 mA, and 30-300 mA. It can also be tailored to customer specification. The relay is professionally designed and calibrated for various sizes and shapes of CBCT suitable for cable entry or busbar. It is available in panel and DIN mounting type, with one pair of changeover contacts.