| LONG DESCRIPTION |
(a) Single pole air blast circuit breaker rated 400 A at aservice voltage of 25 KV similar to type DBTF 30250of M/s.Brown Boveri for electrical multiple unitsoperating on a nominal voltage 25KV , maximum 27.5 KVand minimum 17.5 KV single phase AC, 50C/S . It shallhave a rupturing capacity of 250 MVA with 7KG/sq.cm airpressure at the nominal voltage of 25KV and the trippingtime not to exceed 80 milli seconds. The breaker shallbe suitable for a maximum of 10KG /sq.cm. pressure andprovided with a minimum presure interlock which comes into action at 4.2KG/sq.cm "ON" and 3.5 KG /sq.cm. "OFF".It shall be suitable for roofmounting to worksatisfactorily under worst humid condition with anisolating mechanism with time lag device and controlresistor across the contacts, to effect perfect arcquenching. The supply shall include air drier, nonreturn valve, drain cock and pressure switch andresevoir shall be of ample capacity for a minimum ofthree, ON, OFF, operations with approx. 40 litres airconsumption at 7 KG/sq.cm. per switching operation.The overall dimensions with isolator mechanism closednot to exceed 940 X 750 X 795 mm.ORU.L. No. 39 3176 4034 0101 (Vacuum circuit breaker)(b) Single pole vacuum circuit breaker rated for 600AMPs at a service voltage of 25KV . It should have arupturing capacity of 250 MVA at 25KV and should besimilar to type "20 CB 682 " of M/S.GEC India Ltd.,generally governing to CLW specn.no.CLW/ES/C-27 ALT IIts short time rating should be 10KA for 3 seconds .The holding coil (of magnet valve) should be suitable foroperation on 110 VDC ( with a supply variation ranging from70 to 125 VDC). The total tripping time should not exceed60 milli seconds while operating at 25KV and control airpressure ranging from 4.8KG/sq.cm to 3.6 KG/sq.cm.The breaker should be suitable for max.of 10KG/sq.cm airpressure and provided with eight (auxilliary) interlocking contact (3 N/O + 5 N/C and rated for 10A continuousrating and breaking capacity of 4 amps at 110VDC).The breaker should be suitable for roof mounting onEMU"s motor coaches. the mounting dimension and roofcut out should be identical to ICF Drg . No. ICF/SK/90825.The breaker should be suitable for operation on line voltagevarying from 17.5 KV min.. and 30 KV max. and max.humidity condition. The scope of supply should includesuitable air drier, non-return valve to size 1/2"BSPfemale thread, drain cock and air pressure switch (similarto type RT 116 X of M/S. Danfoss India ltd.,) and two nos.RC surge suppression network as recommended bymanufacturers and as approved by RDSO/LUCKNOW.The VCB shallconform to the RDSO special instructions No.RDSO/ELRS/161(REV.1)regarding seating of cradle cover of VCBalternatively offer may also be made to CLW SPECN.NO. CLW/ES/C-47 ALT NIL. |
