Telescopic Disconnect Switches
High-Current Disconnect Switches for Isolated Phase Bus Systems
Spec Fab IPB provides high-pressure contact telescopic disconnect switches for isolated phase bus systems. Designed for generator, transformer, and circuit breaker isolation, these switches are integrated into phase-isolated, metal-enclosed bus duct assemblies.
Switch assemblies are available in configurations tailored to the electrical, mechanical, and operating requirements of each installation.
Switch Construction & Operation
- Telescopic disconnect switches incorporate high-pressure contacts within individual phase-isolated enclosures. The operating force is transmitted through an insulated shaft to a screw and lever mechanism connected to the moving contact.
Operating configurations:
- Manual or motor-operated mechanisms
- Individual-pole or ganged three-pole operation
- Externally ganged operating arrangements
- Mechanical and/or electrical interlocking
- Positive contact actuation
Inspection & System Integration
Switch assemblies can incorporate viewing windows for direct observation of the isolating gap, with optional photoelectric detection of actual blade position.
Design features:
- Metal-enclosed, phase-isolated construction
- Self-cooled or forced-air-cooled IPB compatibility
- Open-gap withstand capability at the specified B.I.L.
- Visual switch-position inspection
- Optional photoelectric blade-position detection
- Integration into existing or new bus layouts
Electrical Ratings & Design Parameters
- Telescopic disconnect switch configurations are engineered according to the electrical and mechanical requirements of the isolated phase bus installation.
Principal design parameters include:
- Continuous current and short-circuit ratings
- Basic impulse insulation level (B.I.L.), open-gap dielectric withstand, and power-frequency withstand requirements
- Conductor and moving-contact dimensions
- Enclosure diameter and minimum phase spacing
Final equipment dimensions and configurations are determined by the requirements of each application.