Abstract: Disclosed is an apparatus for protecting a three-phase power transmission line, having three power conductors, from intermembral electrical faults. First, second, and third sensing and rectifying means are inductively associated with respective ones of the three power conductors of the power transmission line for generating respective DC signals corresponding to the current flow through the respective, associated power conductors. A first switching means is provided for disconnecting the power transmission line from a power source upon the occurrence of a voltage imbalance between the sensing and rectifying means. Another switching means is provided for temporarily interconnecting the outputs of the sensing and rectifying means before operation of the first switching means, for preventing spurious tripping of the first switching means during sharp increases in power which do not occur as a result of a fault.

Abstract: An apparatus for causing relative movement of first and second structures about a pivot axis is disclosed wherein a rotatable, elongated member has first and second portions which respectively extend from the pivot axis toward the first and second structures. The second portion of the member extends rotatably within a housing which is also rotatable with respect to the second structure. The axis of rotation of the member second portion within the housing is skewed from the axis or rotation of its first portion relative to the first structure by an angle .theta. and is also skewed by an equal angle from the axis of rotation of the housing relative to the second structure. Simultaneous rotation of the housing and member in opposite rotational directions produces arcuate movement of the member first portion and the first structure, about the pivot axis, relative to the second structure.

Abstract: A self steering vehicle for a transportation system including a roadway having a pair of elongated parallel tracks whose shape in cross-section is domed or convex and preferably having a pair of guide flanges positioned outwardly of the tracks, the vehicle having wheels provided with resilient track-engaging means, such as pneumatic tires, and driving means for propelling the vehicle over the roadway. The wheels of the vehicle tend to follow the tracks because of the deformation of the tires if they tend to move laterally off the center portions of the tracks, and the guide flanges engage the tires, upon the wheels having moved off the tracks because of the imposition of excessive side loads on the vehicle, to turn the wheels back onto the tracks.

Abstract: A power controller for transmitting alternating current from a power input circuit to a load, the controller being a master silicon controlled rectifier, hereinafter the "master rectifier," and a slave silicon controlled rectifier, hereinafter the "slave rectifier," connectible in parallel with the load across the input circuit, a capacitor chargeable during positive half cycles for discharging at the zero voltage crossover between half cycles of positive and negative input voltage to render the master capacitor conductive and a second capacitor chargeable When the master controlled rectifier is conductive whose discharge renders the slave rectifier conductive at the instant of zero voltage crossover between half cycles of negative and positive input voltage.