L_V_Circuit_Breakers - Federal Elektrik - #39

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Untitled table.main {} tr.row {} td.cell {} div.block {} div.paragraph {} .font0 { font:6.00pt "Arial", sans-serif; } .font1 { font:7.00pt "Arial", sans-serif; } .font2 { font:8.00pt "Arial", sans-serif; } .font3 { font:16.00pt "Arial", sans-serif; } .font4 { font:6.00pt "Georgia", serif; } .font5 { font:12.00pt "Georgia", serif; } .font6 { font:7.00pt "Palatino Linotype", serif; } LV. CIRCUIT BREAKERS r S t n Even smaii values (>30mA) ot ground fault currenis lo occur In elecirical circuits are quile dange/ous in letms of salety o( life and fire As normal breakeis cannol detect such srnall ground fault currents, no additional protection »s provided against ground leakages Ground fault protection System can be added to elecironic breakers wlihout an additional mechanrsm With this System, protection at (0.1-l)xlnsensilivity can be provided. Protection against ground faults in norv electronic breakers and elecironic breakers needtng protection against leakage currents lower ihan tne value mentioned above is provided with combinaûon of toroidaf transformer and leakage currenl détection retays However, in this System, in order to let the circuit breaker open in ground leakage currents. remote-release coil or low voltage coii should have already been mounted to the breaker {Figure-9). Faull current of the faull current détection retay should be adjusled according lo protection type and appropriate values to ensure selectivity among other détection relays. According to the standards, this values has been determined as 30mA for life protection and (3OO-50O)mA for fire protection Assembly: AH the phases and neutrat cable, if any, shali pass through the toroidai transformer. Ground cable should not pass through the toroidal. Secondary cables of toroidal shall be connectée! to ground leakage détection relay (Z1-17) terminais and appropriate voltage written on the reiay is supplied to energy input terminais of the relay Remote- release coil or low voltage coil must have been connected to the breaker (ri order to open the circuit breaker due to ground faull II remote-release coll has been connected to the circuit breaker. energy supplied to opentng coil should be supplied through open contact ot lhe ground leakage détection coil normally (Figure-10) If low voltage coil has been connected to the circuit breaker. energy supplied to the low voltage coil should be supplied through upper part of the energy breaker and normally closed contact of the ground leakage détection relay (Figure-11). Important considérations in assembly: - Cables should pass through center ot lhe toroidal Iransformer to the extent possible. - Toroids wrth appropnate diameters should be utilized Utilizalion of roroids with higher diameters shall <educe sensitivity Différent Connections: o If cables cannot pass tnrough a tcold with high diameter, several toroids can be connected parailei to the same ground détection relay However, this transaction reduces sensitivity of the device and increases opening threshold o tt il is not possible to place the torold around prtmary busbars, it can De placed on neutral-ground connection of lhe transformer for baianced loads Release coll or low voltage coil jL Faull -.^current f relay •.Toroidal winding Load FIq - 9 Pitifetton swiem m orcuit bteitkers ' !ault curano AC220V LOAD FI : Shunt Tnp netay Fin ■ 10 Use of : _nd faut ornent detectioc System with Bnunt release cott w\ circuit breaKer ■ -, • il- cable should nol pass 'hroujn IoiohI r ■ T x Parahei connwaon ol more than ont lOfW lo a sine?» laull entrent oaleOon coil AC 220V LOAD F2 ; Under Voltage RWeaa» (UVR| Rg-11 Use ol ground laull «eiay wilh unoervottaue lelease m oreuil breaker Cables shoulct not be anrwisted near loraiû FEDERAL 1/4