General SWITCHGEAR
... for safety. The cable box is designed for cable entry from top or bottom. Bus duct entry can also be from top or bottom. Sufficient head room is provided for cable termination. The distance between the cable gland plates and terminal lug is greater than 700mm. For bottom cable entry, a removable 3mm MS a land plate is provided. For single core cable cable, non-magnetic gland plate is incorporated. 4.Relay And Instrument Chamber: The relays and instruments are mounted on a separate chamber. This is totally segregated from High Voltage chamber. The operating instruments are located at a convenient max. height of 1700mm. All relays are mounted on a hinged door. For ease of reading the maximum height is 2000mm.There is provision to increase the height depending on the number of relays. The wire is insulated of 1.1 KV grade and suitable for 2KV, 1mm. p.f. In special cases auxiliary winding conductor size can be increased upto 2.5sq.mm.As a standard practice cables are neatly bunched together with ferrules at either end of each wire. As per application, colour ferrules are provided. The wire bunch is passed through PVC ducts. 5.Earthing: Switchboard earthing: -A copper earth bus of size 50 to 60 mm continuously runs through the bottom of the panel. The earth bus is robust and is capable of carrying full short circuit current for 1 sec. Doors and moving parts are earthed through flexible copper wires. SPECIAL FEATURES: All HV compartments are provided with pressure release flaps. In the event of a fault in any compartment the high pressure finds outlet through release flaps. These are so located to guide the by-products of internal arcing to prevent harm to the operating personal ensuring fail-safe features. The panel is fully insulated through sleeves and insulating shrouds. There is no access to live parts. Circuit-Breaker compartment for the HWX: The circuit breaker compartment receives the trolley which houses the circuit breaker and potential transformer or the control transformer as required. The trolley engagement to the enclosure is of horizontal drawout type. The circuit breaker trolley has three distinct positions-service, test and isolated. As an additional feature, all three positions have latching facility and service and test positions have locking facility. These two positions have limit switches with auxiliary contacts for interlocks. As an additional safety the circuit breaker is operated in service and test position with the cubicle door closed. The test position is within the cubicle. A flexible duty interlocked plug and socket arrangement is used for auxiliary supply. For additional protection, these have scraping earth terminals. Truck movement operates metallic safety shutters with circuit breakers withdrawn, the safety shutters close so that no live parts are accessible. The shutters are lockable in closed position. For higher reliability bus side and cable side have mechanisms All trolleys of same rating are interchangeable and trolley of lower rating cannot be i...