• Protech Engineering & Controls Private Limited

Earth Fault Relays

Protech Engineering & Controls offers Earth Fault Relays, Model N22 – ELR Series. Operation: N22-EFR Series earth fault relays monitor the current flowing through the earth circuit through the secondary of CT, which is in the earth path or all phase CTs are connected parallel and connected to relay signal input. If neutral is also available in circuit, a neutral CT is also connected parallel. When current signal goes out of the range selected on the dial, the relay status will change. The relays are provided with time delays. For earth fault protection of alternators, the CT is connected between the alternator neutral and ground. The N22 relay has two selectable setting range for tripping. Also the relay has wide auxiliary power supply range from 90 to 270 V AC/DC. Special features: most compact yet ultra flexible protection relays; micro controller based true RMS measurement; two tripping ranges in one unit; two time delay ranges in one unit; user selectable normal/fail safe modes; user selectable auto/manual reset; and wide power supply range from 90-270 V AC/DC. Technical data: supply voltage – 90-270 V AC/DC; output contacts – one change over (potential free); switching duty – 6 A resistive at 250 V AC or 24 V DC; electrical life – 10 operation at designed switching duty; relay status – normal = de-energised in normal conditions, fail safe = de-energised in fault conditions; signal – from CBCT/1 A-5 A CT; ranges – A = 10-100% (0.5-5 A for 5 A CT sec), B = 050-100% (2.5-5 A for 5 A CT sec); time delays – 0.1-1 sec/1-10 sec; reset – user selectable auto/manual reset; mounting – DIN channel; approximate weight – 100 gm; and dimensions – 22.5 (W) x 110 (D) x 73.5 mm (H). Applications: distribution panel boards, motors/pump panel boards, generators, transformers, etc.