• Navago Electronics and Electricals

Earth leakage relay

Navago manufactures earth leakage relay in ELR and ELR-2 types. This relay is used on AC systems and is a sensitive electronic protection device. Its operation on earth fault is independent of the system voltage imbalance. It can detect earth fault currents as low as 1 A, which is 0.25% in a 400 A feeder system. This can be used on a single-phase or on a three-phase network. It operates on the core balance principle. The relay is housed in a robust insulated enclosure. The electronic circuit has a voltage developer, a level detector and a static switch, which drives an electro mechanical, an electro mechanical relay. The terminals of this are connected to switchgear. The relay is provided with a TEST push button for checking its operation and a RESET push button to reset the relay on operation. This built-in test feature enables the quick check of the proper functioning of earth leakage relay. The relay is also offered in flush mounting design of standard 96 or 144 mm square type (ELR-2).Specifications: leakage current setting - from 15 mA onwards as desired; core balance CT - Toroidal core, bar primary; auxiliary supply - 230 V AC or 110 AC, 50 Hz, 1 phase; built-in relay contact - 5 amps (resistive), 415 V AC or 220 V DC; and number of contacts - one N/O and one N/C. Type ELR relay can be used to detect earth leakage currents up to a maximum of three feeders simultaneously. The relay contacts can be connected to an alarm to give signals or otherwise can be made to initiate tripping of all the terminals during leakage. One set of N/O and N/C change over contacts is given in the auxiliary relay. If required two changeover contacts can be provided.