Metal clad gum filled switchgear

Abstract

Metal clad gum filled switchgear has recently been developed using well-known standard American types of round tank, oil tight oil circuit breakers. This metal clad gear has important advantages over previous types of open or cell gear in the features of safety, compactness, service, maintenance and installation. Busses, etc., are mounted on micarta and are insulated and sealed in a gum of high dielectric value. The oil circuit breakers are raised to their bus contacts either by means of a common truck or by individual lifting mechanism per compartment. Very compact accessories, such as oil disconnecting switches, potential transformer assemblies, etc., are used. With the high factor of safety provided for the bus, etc., the old standard double-bus scheme is not necessary as a spare bus, though a transfer bus is valuable to permit inspection of any breaker without interruption of service. A description is given of various installations, including the large isolated-phase, outdoor switchgear under construction at Leaside Station, Toronto.