Abstract: A ground fault interruption circuit detects a ground condition associated with a load in an electrical distribution system and disconnects the load in response to a ground fault condition. The circuit includes a ground fault detector connected to receive a ground fault imbalance signal and operative in response to a power signal, having specified voltage and current levels, to provide a trigger signal to disconnect the load from the system when the imbalance exceeds a certain level. A regulated power supply circuit a substantially constant current and voltage signal to the detector to minimize excess power to the detector and heat loss. The power supply includes a start up and storage portion and a constant current supply portion.

Abstract: A ground fault interruption circuit has a detector circuit coupled to an electrical distribution circuit load to detect ground fault conditions in the load. A filtering circuit connected between the detector circuit and distribution network comprises a pi-network filter for attenuating common-mode electromagnetic interference and differential-mode electromagnetic interference. The pi-network filter includes three filter portions which together provide a third order filter to attenuate the interference signals at the frequencies of interest.

Abstract: A circuit breaker has a pair of poles, either of which can experience a ground fault. A sensing device senses an imbalance of current between the phases and neutral, and a trip device responsive to the sensing device simultaneously trips both of the poles when an imbalance of current (ground fault) is sensed in either of the poles. The trip device includes a trip lever engageable with each of the poles and a single solenoid for controlling operation of the trip lever.

Abstract: Apparatus for cross-folding paper sheets, including: a first folding device for imparting a first fold to a paper sheet; a transport module secured to the first folding device for receiving a once folded paper sheet, and a second folding device oriented perpendicular to the first folding device and secured to the transport module, wherein the transport module includes a pivotable paper stop assembly having a self-centering stopping surface to stop and align the once folded paper sheet and a brush for controlling bounceback of the once folded paper sheet.

Abstract: A cooling system for cooling steel slabs or the like comprises an elongated tank with parallel rollers for conveying the heated slab horizontally beneath the surface of a water bath. Water curtains from angularly directed upper and lower nozzles seal the entry opening in the end of the tank through which the slab is introduced into the tank and also supply cooling water to the tank. The rollers have axially spaced disk portions for supporting the slab in spaced relation above guide plates or aprons extending between the rollers. Inlet cooling water from the lower water curtain impinges against the lower surface of the slab and is diverted into and flows at high velocity through the restricted cooling channel defined between the guide plates or aprons and the underside of the slab. In a continuous form of the cooling system, a water curtain sealed outlet opening for the slabs is also provided in the opposite end of the tank. Intermediate cooling water nozzles may also be provided between the ends of the tank.