Abstract: There is provided by this invention a vacuum monitoring device for use in vacuum circuit interrupters comprising a stacked resistor assembly as a voltage divider coupled to an internal shield of the vacuum bottle and a low voltage detection circuit for monitoring leakage currents under abnormal pressure conditions.

Abstract: There is proved by this invention a novel metal clad switchgear construction wherein the exterior walls are recessed to form areas disposed to provide ventilation shafts between adjacent units and increased access to the primary terminals.

Abstract: A vacuum circuit interrupter as taught which utilizes the vapor deposition shields thereof in the existing high voltage source or network which is controlled by the circuit interrupter to produce a cold cathode ion detector for determining the quality or amount of vacuum within the vacuum circuit interrupter. The central shield support ring which protrudes through the insulating casing of the circuit interrupter is used to supply ion current to a current detecting bridge through a circumferentially insulated surge resistor and from there to the common terminal of the aforementioned voltage source to thereby return one of the plates of the ion detecting device to the voltage source.

Abstract: Metal-clad switchgear utilizing means to provide for self-cooling of the current transformers and primary disconnecting contacts. The support enclosure for the current transformers and the disconnecting contacts is apertured beneath the location of the current transformers, and air may enter the enclosure to cool the current transformers and contacts. A ventilating duct is in fluid communication with air within the enclosure, and transports the heated air from the enclosure to exhaust vents situated at the top of the metal-clad switchgear housing.

Abstract: A hollow, cylindrical, copper, tubular conductor is taught. One end of the tubular conductor is beveled or rounded off for convenient insertion into a fingered circular disconnecting contact for circuit interrupter apparatus. The other end of the tubular conductor is spun or bent over a captured circular flange. The circular flange has tapped holes or push nuts inserted therein through which bolts may be threaded. A flat bus bar riser having corresponding holes therein is abutted against the flattened end of the tubular conductor at right angles thereto and securely fastened thereto by bolts which extend through the complementary holes into the flange. A method is taught for securing the flange to the copper tube and for attaching the riser thereto.

Abstract: A washer is disposed axially on a bolt between two portions which are to be secured by the bolt. The portions have holes or openings therein, which are larger than the diameter of the bolt for providing a range alignment between the portions and the bolt. The washer has a sharp circumferential lip edge on each side thereof which is generally parallel to the axis of the bolt. The edges protrude into the respective portions once the bolt has been axially tightened to thereby secure the portions in a predetermined disposition relative to each other. Lateral movement of the portions relative to each other is thus prevented or reduced.

Abstract: A circuit breaker characterized by spring means for closing contacts, means for charging the spring means and including a crankshaft structure, a ratchet wheel rotatably mounted on the shaft, driving pawl means operable to advance the ratchet wheel for charging the spring means, an oscillating drive pawl structure in driving engagement with said ratchet wheel, means operable to oscillate said drive pawl structure and comprising a bight portion movable across the axis of the output shaft of a charging motor.