Showing papers by "General Cable published in 1974"

Electrical and Electro-Chemical Treeing Effect in Polyethylene and Crosslinked Polyethylene Cables

Abstract: Numerous polyethylene (PE) and crosslinked polyethylene (XLP) cable samples recovered from the field after one to seventeen years of service have been studied in relation to treeing phenomena. Special test circuits for laboratory growth of electrical and electro-chemical trees have been developed. Based on numerous tests, general recommendations for minimizing the treeing effect in PE and XLP cables as well as for testing these cables for tree development have been made.

Extruded solid dielectric high voltage cable resistant to electro-chemical trees

Abstract: Extruded dielectric power cables installed underground have their life shortened by the formation of electrochemical trees in the insulation. Tree formation can be prevented if the insulation is initially dry and the cable construction is such that moisture cannot gain access to the insulation under operating conditions encountered during installation and underground use. This invention eliminates initial moisture and has a construction that greatly retards ingress of moisture to the insulation during installation when the cable is in service and prevents longitudinal movement of water along the cable due to accidental damage to the cable or electrical failure.

Hydraulic system with bi-rotational pump with filter title

Abstract: An hydraulic system employing bi-rotational pumps for directing fluid under pressure to an actuator. In one embodiment the return fluid from one port of the actuator is filtered by means of a pilot operated check valve in a by-pass circuit leading to a filter and fluid reservoir, with an additional check valve being provided to preclude flow from the by-pass circuit to the associated port of the pump. In another embodiment return flow from the head end of the actuator is directed to a filter and reservoir by a two way control valve which also functions to direct flow from the pump to pressurize the head end of the actuator. A pilot operated check valve is provided to direct flow from the head end of the actuator directly to the reservoir even should the two way control valve be inoperable. In another embodiment duplex bi-rotational pump systems provide high volume flow rate at a relatively low pressure, or a low volume flow rate at a relatively high pressure. In one embodiment of the duplex bi-rotational pump system a circuit is provided to filter the fluid returning from the actuator to the reservoir by means of a two-way flow control valve.

Hydraulic System with Bi-Rotational Pump

Abstract: An hydraulic system employing bi-rotational pumps for directing fluid under pressure to an actuator. In one embodiment the return fluid from one port of the actuator is filtered by means of a pilot operated check valve in a by-pass circuit leading to a filter and fluid reservoir, with an additional check valve being provided to preclude flow from the by-pass circuit to the associated port of the pump. In another embodiment return flow from the head end of the actuator is directed to a filter and reservoir by a two way control valve which also functions to direct flow from the pump to pressurize the head end of the actuator. A pilot operated check valve is provided to direct flow from the head end of the actuator directly to the reservoir even should the two way control valve be inoperable. In another embodiment duplex bi-rotational pump systems provide high volume flow rate at a relatively low pressure, or a low volume flow rate at a relatively high pressure. In one embodiment of the duplex bi-rotational pump system a circuit is provided to filter the fluid returning from the actuator to the reservoir by means of a two-way flow control valve.

High voltage solid extruded insulated power cables

Abstract: This electric power cable, and method of making it, relate to high voltage cables with solid extruded insulation, and the life of the cable is lengthened by protecting the insulation from localized voltage stresses which cause emission of electrons into the insulation. An emission shield is used between a semi-conducting conductor shield and the insulation that surrounds the conductor shield; and preferably, for higher voltage cables, an emission shield is used between the outside of the insulation and a semi-conducting insulation shield.

Procedure for copper plating aluminium wire and product thereof

Abstract: This method of copper plating aluminum and aluminum alloy wire or strip applies an adherent and ductile plating while the wire is moving rapidly and continuously through the plating apparatus. An improved chemical zincating step followed by a copper pyrophosphate strike plating, within critical thickness limits, reduces the plating time and makes practical plating of the wire while moving at speeds of about 100 feet per minute or more in relation to the processing solution.

Twisting machine flyer bow

Abstract: This flyer bow is for a machine used for twisting together communication cable wires to make conductor pairs, or twisting together large numbers of wires. The bow has a recess into which the twisted wires can nest and be held by centrifugal force in a position away from the windage caused by the rapid rotation of the bow in an orbital path. This prevents a loop from forming in the twisted wires as sometimes occurs in machines where windage overcomes the centrifugal force and wire tension. This invention permits operation of twisting machines with lower wire tension.

Drop in anchor stud

Abstract: The stud, pin or the like of this invention is used in a blind hole in masonry or similar material. It has a threaded upper end and some distance below the upper end the stud is necked down and garroted with a tapered, frusto conical portion below the neck for expanding a collar which surrounds the neck. The collar is a split ring which has to be compressed to fit into the hole, and upward pull on the stud causes the frusto conical portion to expand the stud and firmly secure it in the wall or other object in which the hole is located. The collar is shaped to prevent it from rotating in the hole.

Aerial lift platform leveling apparatus and system

Abstract: Apparatus and system for leveling the work platform or basket of an aerial lift. A vertical seeking pendulum is mounted on the boom of the lift independent of the platform. Changes in the relative angle between the pendulum and boom are transposed into control signals by means of an epicyclic gear train. The control signals operate an actuator for pivoting the platform in a direction to maintain a level orientation. Platform movement relative to the boom generates a feedback signal which is carried through the epicyclic gear train to cancel the control signal. In one embodiment the pendulum is damped by means of a pair of balls guided in a circular raceway so as to follow the pendulum independent of the boom position. In another embodiment pendulum movement is damped by means of a viscous liquid constrained within a housing so as to surround the pendulum independent of boom position. The system includes a control circuit incorporating a reversible pump selectively operable in one mode to direct fluid to the leveling actuator and through a two-way valve into an hydraulic actuator for raising and lowering the boom, and in another mode to direct fluid to the leveling actuator for moving the platform to its stowed position. An emergency supply circuit directs return fluid from the boom actuator to the leveling actuator as the boom is lowered should the primary hydraulic power source by inoperable for any reason.

Communication cable with improved coated shield

Abstract: This communication cable has a metal shield coated with a corrosion protecting coating of polyethylene blended with an adhesive copolymer to control the adhesion of the coating. A jacket is extruded directly over the outside of the coated shield and is uniformly bonded to the coated shield. The bond to the metal is strong enough to prevent delamination of the coating from the metal and the cable is buried and exposed to ground water; but the bond of the coating to the metal is limited enough to permit the coating on the outside of the shield to be peeled from the metal at cable ends and splices so as to expose bare metal.

Normal and Short Circuit Operating Characteristics of Metallic Shielded Solid Dielectric Power Cable

Abstract: Experimental results are presented on the normal and short circuit operating characteristics of metallic shielded solid dielectric power cable. Test data on thermal runs of single conductor shielded power cable under typical installation conditions confirm published ampacity data1, and hence the theoretical procedure2 employed for calculating the ampacity of single conductor cable with circulating current losses. The thermal runs also point out the possible adverse effect on the cable of operating at a high interface temperature for an extended period of time.

High voltage flexible cable supported by a continuous rigid bridge for floating platforms

Abstract: This invention carries a power cable from a floating power plant to a fixed connection from which the power cable can transmit to a distributing system on shore. The cable support distributes the bending of the cable over a length of cable so that no deterioration of the cable occurs as the result of successive bending and unbending with the tidal motion of the floating power plant. A jointed cover protects the cable support from exposure to the weather and from icing.

Influence of electrochemical trees on the electrical properties of extruded polymeric insulation

Abstract: The existence of electrochemical trees in high-voltage extruded-type cables installed in numerous locations was first examined and reported by Lawson and Vahlstrom.1 An analysis and further laboratory studies of this phenomenon was reported by Bahder et al.2 This reference paper defines electrochemical trees caused by ingress of moisture from the environment and demonstrates that, under highly accelerated test procedures, this type of tree formation can be generated within weeks in the laboratory when frequency acceleration is used. The correlation between electrochemical treeing and the electrical properties of selected commercial insulations used on underground cables was further analyzed by Bahder et al. 3 This analysis discusses the various mechanisms of tree formation in extruded type cables exposed to moisture and indicates the role that electrochemical tree growth plays in electrical properties.

Design and Installation of a 138-KV, High-Pressure, Gas-Filled Pipe Cable Utilizing Segmental Aluminium Conductors

Abstract: This paper presehits the results of further developments of 138-kV cable impregnated with extra-high-viscosity oil, as well as those of joining aluminum conductors and terminal ferrules by the inert gas shielded arc welding method. Welding the conductors in the presence of heavy oil had presented the chief deterrent to commercial utilization of cable containing alumliinum conductors. Success of these investigations has resulted in installation of a 2.74 mile (4.41 km) portion of The Detroit Edison Company Medina-Stephens 120-kV line, commissioned in November 1971. That installation is reported upon herein.

Nonlinearity in Impulse Breakdown of Very Large Air Gaps

Abstract: Optical and electrical measurements of positive impulse discharges, in a point-to-plane electrode configuration, have been performed for electrode spacings ranging from I to 7 meters. A comprehensive analysis of these results indicates that the breakdown mechanism above 5.2 million volts (MV) differs from the mechanism operating at voltages below this level. A new extrapolation method for breakdown voltages levels above the measurable range has been developed. This method permits the determination of positive impulse breakdown voltage for very large gap spacings up to 14 meters, well above the maximum capabilities of presently available voltage sources. This study provides essential data contributing to a feasibility study of future UHV overhead systems.