 DISCONNECTING SWITCHES Introduction Disconnecting switches of the high pressure contact type are often used to isolate generators, transformers or circuit breakers. They are built into phase isolated compartments and are designed to be mounted integrally into the bus layout. Disconnecting switches are externally gang operated, have the necessary inter-locking, and can be controlled both electrically and mechanically from a remote location. They are available for all normal continuous current and short-circuit ratings and are equipped with a window to permit visual inspection. Photo-electric detection of the switch position is also available. Application Disconnecting switches are used in isolated phase metal enclosed bus ducts as circuit isolators. They are also used for phase reversal operations in pumped storage stations. Features
Operating Mechanism Little effort is required to operate the switch. Manual or motor operating mechanisms are available for individual pole or ganged three pole operation. The operating force is transmitted by means of an insulated shaft to a screw and lever type mechanism connected to the moving contract. This ensures positive operation of the switch movement. Auxiliary Switch Positive action, multiple contact auxiliary switches are available with up to 40 amps continuous current carrying rating. Auxiliary switches are mounted externally to the disconnect switch and function from the operating shaft. Photocell operation is optional. Maintenance Regular Visual checking of operating parts and bolted connections eery 18 months. General Overhaul Monitoring of insulators, bolted joints and lubrication of moving parts and contacts every 3 to 4 years. Disconnect switches are presently in service in North and South America with ratings up to and including 19,000 amps, 170 kV B.I.L. |
