Three Position, Rotary Blade Contact Principle

G&W's rotary blade contact system permits three position switching capability within a single compact switch. The rotary blade contact system is modular in design and capable of alignment checks and bench testing prior to placement in the switch tank. The switching module is connected to the external operating shaft by means of a sliding coupling. The coupling provides the module with mechanical freedom from the tank walls thereby reducing stress or misalignment due to changing pressure conditions and subsequent deflection of the tank walls.

The switching mechanism is a compression spring operated device which latches in both the open and closed positions to ensure proper contact opening during interruption and closing under normal or fault conditions. The speed of the contacts is independent of the movement of personnel or devices externally operating the switch.

The rotary blade contact system is comprised of plated copper moving contact blades which mate with plated beryllium copper stationary finger contacts. The moving blade is mounted on a molded rocker arm and is connected to either a bus bar or entrance bushing using flexible wire rope. The stationary contacts are supported independent of the cable entrance bushings, eliminating possible misalignment resulting from tank deflections. Tank deflections are caused by normal tank pressure variance due to ambient temperature fluctuations. Reinforced flaps mounted to each moving contact blade forces SF6 gas into the arc zone for more efficient interruption. The flexible rope removes the necessity of critical contact alignments.