Short Term ETD/MT/T-01/2026-27

Overhauling of 145 KV, "ABB/Siemens/CGL" make 03 Nos. SF-6 Circuit Breakers of CB-783 63 MVA T/F-III, CB-781 40 MVA T/F-I & CB-74 (132 KV Shatabdinagar-Medical College line) shall required to be carried out consisting of following works: (1) Opening/Dismantling of control valve assembly, cleaning of cap seal cylinder, removal of defective roller and re-fixing of new roller, reassembly of control valve assembly in mechanism. Replacement of control valve seal and bent “O” ring. (2) Opening of anti-pumping pin assembly, cleaning, de-rusting & lubrication of anti-pumping pin assembly. Re-fixing of above assembly at proper place. (3) Opening and cleaning of closing spring, shock absorber, pneumatic cylinder cleaning of piston and cylinder including their assembling. (4) Opening & re-assembling of trip coil assembly after cleaning of its various parts including measurement of coil resistance, adjustment of trip coil gap. (5) Opening & re-assembling of closing coil assembly after cleaning of its various parts including measurement of coil resistance, adjustment of closing coil gap. (6) Checking of “NRV” drain valve for air leakage with the help of soap seeds. Replacement of NRV & repairing of drain valve. (7) Checking of air switches i.e. governor switches, low air pressure alarm switch, air lockout switch etc. including adjustment of all. (8) Checking of gas density switch including all adjustments during & after filling of SF-6 Gas in circuit breaker. (9) Checking of control wiring in marshaling box & tightening of electrical connections etc. (10) De-rusting, lubrication of horizontal rod assembly and its various linkages. Cleaning of bar pins, replacement of circuit if needed. (11) Slow operation of circuit breaker with the help of manual jack for checking over-stroke, wire poles & travelling etc. (12) Smooth operation of circuit breaker from local as well as remote manual tripping of breaker. 01 Job/No.