Abstract: An electrical switch assembly including a plurality of main electrical switches, an operating device for opening and closing the main switches, and a single interrupter switch connected in parallel with the main switches and operable by the operating device. The interrupter switch opens only after any of the main switches opens, so that the single interrupter switch serves as the arcing contacts for all of the main switches. The operating device may include a shaft which is rotatable to operate the main switches and which is shiftable longitudinally to operate the interrupter switch. The shaft may carry a radially projecting follower pin slidable within a fixed guide slot shaped to insure the desired sequence of operation of the plurality of main switches and the interrupter switch. The interrupter switch, which may be a conventional circuit breaker, is a self-contained unit physically separate from the main switches.

Abstract: An arrangement including an automatic transfer switch, a bypass switch, and mutually cooperable pairs of contacts for electrically connecting the two switches. The entire transfer switch is movable as a unit toward and away from the bypass switch to engage and disengage, respectively, the cooperable pairs of contacts, disengagement of the contacts serving to isolate the transfer switch from the bypass switch and from the power sources and load. The transfer switch cannot be isolated from the bypass switch when the latter is open. The bypass switch can only be closed in a direction which connects the load to the same source of power to which the load is connected through the transfer switch. Each mutually cooperable pair of contacts engage each other solely by friction. There are at least three cooperable pairs of contacts, for connecting the transfer switch to a normal source of power, to an emergency source of power, and to a load, respectively.

Abstract: A valve having a valve body formed with an internal orifice between the valve inlet and outlet ports, and a main valve member for opening and closing the orifice. A chamber above the valve member is supplied with high pressure fluid through a bleed passageway extending between the chamber and the inlet port. A pilot valve controls exhausting of the chamber when the main valve is to be opened. A flow control element in the bleed passageway maintains a constant rate of fluid flow for filling the chamber, to close the main valve, regardless of the pressure differential across the flow control element. The bleed passageway may be in either the valve body or the main valve member. The flow control element may be an annular rubber washer.

Abstract: An automatic transfer switch having two sets of phase switches, one set for connection between a normal power source and a load and the other set for connection between an emergency power source and the load. The transfer switch also includes two neutral switches, one for connection between the normal source neutral and the load neutral, and the other for connection between the emergency source neutral and the load neutral. Only one set of the phase switches can be closed at any one time, and during transfer of the load from one source to the other both sets of phase switches are open. Prior to a transfer operation, the neutral switch corresponding to the closed set of phase switches is closed and the neutral switch corresponding to the open set of phase switches is open. During transfer of the load, both neutral switches are closed before the closed set of phase switches open and both neutral switches remain closed until after the closed set of phase switches open and the open set of phase switches close.

Abstract: An automatic transfer switch having two sets of phase switches, one set for connection between a normal power source and a load and the other set for connection between an emergency power source and the load. The transfer switch also includes two neutral switches, one for connection between the normal source neutral and the load neutral, and the other for connection between the emergency source neutral and the load neutral. Only one set of the phase switches can be closed at any one time, and during transfer of the load from one source to the other both sets of phase switches are open. Prior to a transfer operation, the neutral switch corresponding to the closed set of phase switches is closed and the neutral switch corresponding to the open set of phase switches is open. During transfer of the load, both neutral switches are closed before the closed set of phase switches open and both neutral switches remain closed until after the closed set of phase switches open and the open set of phase switches close.