REPAIRS OR MAINTENANCE OF OVERHEAD (OH) LINES AND UG CABLES, INCLUDING ROUTINE, PREVENTIVE AND BREAKDOWN MAINTENANCE OF TRANSFORMERS, AB SWITCHES, LIGHTNING ARRESTERS(LAS), EARTHING SYSTEMS AND ALL ASSOCIATED ALLIED ELECTRICAL WORKS AT DGQA

Taking down HT switch gear (Vacuum circuit breaker ) of capacity 400 to 800 Amps, 11 KV 250 to 450 MVA comprising of following repairs, overhauling, servicing and refixing the same after repairs/ overhauling: (A) Tripping off the breaker, lowering the breaker with raising/lowering handle and pulling out the breaker complete from the panel along with the trolley for servicing/inspection/overhauling.

(B) Servicing/Inspecting/checking of automatic safety shutter operation for serviceability and replacement of spares if required. (C) Servicing/Inspecting/checking of circuit spout and cicuit spout connections for RYB phases and replacement of spares if required. (D) Dismantling and checking of cross bar assembly, fixed contacts and current carrying parts of the breaker, trolley, insulated assembly and checking lamination with clamps, epoxy spout, isolator assembly etc. (E) Setting, reassembling, cleaning, adjustment of fixed contacts, main contact, arcing contacts and chamber baffle pot assembly, moving contact for proper setting of auxiliary contacts operating mechanism. (F) Servicing/Inspecting/checking of secondary sockets/busbar earthing plugs/earthing sockets and replacement of spares if required. (G) Checking, setting and adjustment of lowering and raising operation of the breaker trolley. (H) Lubrication and greasing of all moving parts of the trolley, stopper bolt for proper operating and closing of shutter gear, isolation of trolley of with vacuum interrupter assembly.

(G) Checking, setting and adjustment of lowering and raising operation of the breaker trolley. (H) Lubrication and greasing of all moving parts of the trolley, stopper bolt for proper operating and closing of shutter gear, isolation of trolley of with vacuum interrupter assembly. (I) The inspection of HT switch gear shall involve:- (i) Inspection of truck & hoist assembly. (ii) Inspection of tank assembly & barriers. (iii) Inspection of assembly & components of solenoid assembly. (iv) Inspection of assembly & components of dependent mechanism. (v) Inspection of assembly & components of spring box mechanism. (vi) Inspection of motor mechanism spring charge assembly (vii) Inspection of assembly of trip unit & related components. Notes: (i) The rate quoted shall be deemed to include for necessary T&P, nuts, bolts, washers, gasket, insulation tape, compound etc. to put in to the VCBs and panels in serviceable condition, testing and commissioning all as specified and as directed by the Engineer-in-Charge. (ii) Major spares like Breaker bushings, vaccum interrupter assly, busbar spout, busbar spout connections, circuit spout/circuit spout connections/buffer fixed contacts, moving contacts, tank assly/barriers, solenoid spares, /spring mechainsm/ motor mechanism, trip unit etc will be measured and paid separately under relevant items of Schedule 'A'. However the rate quoted shall be deemed to include for any other minor spares require replacement.

M&L for opening the HT panel of rating 11 KV, 3 phase comprising of following repairs, inspecting, overhauling and servicing/ re-fixing of the spares etc complete all as directed: (a) Dismantling the complete instrument chamber/ HV cable box/LV cable box .Decarbonising/ cleaning the complete HT 11 KV 3 phase independent bus bar, bus bar chamber of HT panel and inspecting the bus bar insulators. (b) Checking, inspecting of IDMT relays complete. (c) Checking complete electrical tripping circuit of HT panel including control wiring from secondary system tripping coil, auxiliary switch male and female housing cut out, etc. and wiring including replacement of damaged wire at places including operation on DC system, testing and commissioning complete all as directed. (d) Inspection of CTs and PTs if any. Replacing the defective CT/PTs incl accuracy in checking of the CT wiring with primary and secondary injection kit including identification to the base and connecting links to main switch including taking down unserviceable current transformer complete all as directed. (e) Inspecting of indicating lamps, rotary switches/selector switches, toggle switches etc complete Notes: (i) The rate quoted shall be deemed to include for necessary T&P, minor spares like nuts, bolts, washers, gasket, insulation tape, lugs, compound etc. to put in to the HT Panels in serviceable condition, testing and commissioning all as specified and as directed. (ii) Major spares like CTs, PTs, IDMT relays, ammeters, voltmeters, indicator lamps, control wiring, rotary/selector & toggle switches etc shall be measured and paid separately under relevant items of Schedule 'A'. However the rate quoted shall be deemed to include for any other minor spares require replacement.

Opening/Closing push button Assembly

Spring charging motor and Gear Assembly

Limit Switch Assly including connected control wiring etc

TNC Switch

Closing Coil