Abstract: An explosion proof power supply enclosure for hazardous atmosphere lighting systems having multiple, identical explosion proof inlet and outlet openings to handle both high voltage AC circuits and low voltage DC intrinsically safe circuits. Each enclosure has thick, flat metal plate end walls and a plurality of identical circular openings located side-by-side in such walls. Each opening has an internal smooth walled surface configuration defining one side of a flame-quenching path. For AC power connections, explosion-proof receptacles are fitted in some of the openings with each receptacle having external surface configurations that define the other side of the flame quenching path.

Abstract: A luminaire comprises a transparent enclosure tube, a cylindrical handle housing at one end of the tube, and a cylindrical cap housing at the opposite end of the tube. A light carriage within the tube comprises a unitary subassembly consisting of a rigid reflector having light bulb holders at opposite ends and a fluorescent bulb secured between the holders. The light carriage is removeable and replaceable as a unit without tools through an open end of the tube by unplugging it from and plugging it into a contact receptacle in the handle housing. Complementary plug and socket formations in the handle housing and light carriage assure alignment of bulb contacts. The housings have castellated ends engageable with detents on mounting brackets on a base to hold the luminaire and to direct light in a selected direction. The cap housing has a telescopical end section which is manually moveable against a spring to release the luminaire from the base without tools.

Abstract: This invention prevents a circuit breaker from being re-set for a time sufficient to insure safe dissipation of ionized gases. Current monitors and rectifiers generate a reduced voltage direct current output which is fed into an auxiliary rectifier circuit. That direct current output is proportional to current in power conductors controlled by a circuit breaker. A holding circuit has an electrical power source derived from the power conductors and connected to a release coil for the main power contacts in the circuit breaker. A holding relay has a holding coil in the rectifier circuit, and normally closed holding contacts in the holding circuit. A time switch is connected in shunt with the holding coil. When the direct current output reaches a value corresponding to an overcurrent condition in the power conductors, it energizes the holding coil to open the holding contacts and cause the release coil to trip open the main contacts. Concurrently, the time switch activates; after a predetermined time (e.g.

Abstract: A reversing switch comprises a mounting plate assembly with a hub extending forwardly through a wall of an explosion proof enclosure. A shaft is journaled for rotational and axial movement in the hub. A stationary contact assembly includes four circumferentially spaced contacts. A moveable contact assembly includes four circumferentially spaced contacts mounted on the shaft. The shaft extends through an external operator member at the forward end of the hub. The operator member is connected to the hub by a groove and flange arrangement preventing fore and aft movement but enabling rotational movement about the hub. A pair of forwardly extending side walls each with a transverse guide slot are connected to the operator member. A handle member with a pair of combined lever and cam arms is connected to the operator member and the shaft.

Abstract: A flame arresting ventilated wall or panel for an explosion-proof enclosure comprises a stack of aluminum sheets apertured to provide a plurality of discrete, generally parallel gas flow channels disposed in crisscross patterns across the heights and widths of the sheets. Fasteners tie the sheets together into a rigid structure and are disposed in patterns surrounding and individually uniformly supporting the gas flow channels from the center of the sheets to their outer edge. Combinations of three different punched sheets are used, namely, first and second apertured sheets spaced apart by relatively thin separator sheets. Along each of the plurality of gas flow channels, each separtor sheet has a large window and the first and second apertured sheets have separate arrays of nine and sixteen flow holes, respectively, registered with the windows, each array having a total cross-sectional area about one-fourth of each corresponding window.