Abstract: A multi-layer armature winding for large turbine generator is wound with individual diamond coils around to the point where the sides of initially wound diamond coils lying in upper armature slot positions interfer with the placement in lower slot positions of the coil side of additional diamond coils to complete the winding. To avoid having to "raise the jump" the winding is completed using bar coils, individual bars of which having been laid in those lower slot positions prior to the placement of any diamond coils. The remaining bars are laid in the vacant upper slot positions and then electrically joined with the initially laid bars to complete the individual bar coils.

Abstract: A turbine rotor disassembly, handling and reassembly apparatus employs a feedback-controlled electric heating oven to rapidly heat a turbine wheel while the rotor shaft is in the horizontal position. An adapter interfaces the wheel to a handling spool whose outboard end is adjusted to slide on the rotor shaft and to provide a fulcrum for supporting the wheel. A handling trolley includes a soft hydraulic system for supporting the weight of the wheel to avoid damaging the precision machined surfaces of the shrink-fit area while the wheel is being withdrawn. The handling apparatus also provides means for upending, or rotating, the removed wheel through 90 degrees to place its axis vertical for facilitating handling. A sensor system senses a radial motion of the wheel to detect clearance and to establish an appropriate fluid pressure to just balance the weight of the wheel and attached parts. The handling system includes means for rotating the wheel slightly during reassembly to align keyways or the like.

Abstract: A dual voltage distribution transformer is protected by an internally installed, multi-rated surge arrester which is selectively connected with plural primary windings by a dual voltage switch such as to establish a high surge voltage protection level when the primary windings are connected in series by the switch and a correspondingly lower surge voltage protection level when the primary windings are connected in parallel by the switch.

Abstract: To reduce the tendency of ground faults and short circuits on electrical heating elements operating at elevated voltages and temperatures, resistance heating wire is coated with a sublayer of magnesium zirconate followed by an outer layer of aluminum oxide; each layer being in the range of 0.001 to 0.010 inches thick.

Abstract: To compensate for voltage ratio errors in a cascaded core instrument potential transformer, the coils of an outer coupling winding otherwise utilized to magnetically couple an adjacent pair of cores together are electrically connected into the primary winding circuit to either add its turns to or subtract its turns from the primary winding turns in order to bring the secondary winding output voltage within acceptable accuracy tolerance limits.

Abstract: A turbine rotor disassembly, handling and reassembly apparatus employs a feedback-controlled electric heating oven to rapidly heat a turbine wheel while the rotor shaft is in the horizontal position. An adapter interfaces the wheel to a handling spool whose outboard end is adjusted to slide on the rotor shaft and to provide a fulcrum for supporting the wheel. A handling trolley includes a soft hydraulic system for supporting the weight of the wheel to avoid damaging the precision machined surfaces of the shrink-fit area while the wheel is being withdrawn. The handling apparatus also provides means for upending, or rotating, the removed wheel through 90 degrees to place its axis vertical for facilitating handling. A sensor system senses a radial motion of the wheel to detect clearance and to establish an appropriate fluid pressure to just balance the weight of the wheel and attached parts. The handling system includes means for rotating the wheel slightly during reassembly to align keyways or the like.

Abstract: Automated gas chromatographic apparatus is utilized to analyze various gases dissolved in the insulating oil of an oil-filled power transformer in an expeditious and reliable manner. A sample of the insulating oil is introduced into a sample loop via a sampling valve, from which it is propelled by an inert carrier gas into a degassing chamber comprised of a vertically oriented tube packed with spherical packing elements. The carrier gas sweeping upwardly through this tube strips the various gases out of solution for conveyance by the carrier gas in plug flow fashion to a gas chromatograph where the stripped gases are separated and individually analyzed.

Abstract: A core loss tester employs separate cables for excitation and pickup. Testing is performed at a fixed flux density in the ferromagnetic core. A processing circuit on the output of the pickup coil scales the voltage developed so that, when excitation current is increased so that the indicated output of the pickup coil equals the effective cross-sectional area of the flux path, the fixed predetermined value of flux density is produced. When this condition is achieved, the excitation current times the sensed flux-induced voltage provides a measurement of the core loss in watts. Excitation is accomplished with a multi-conductor cable looped once or more times through the core with the conductors in the cable connected in series by mating together of a connector at each end.

Abstract: A turbine rotor disassembly, handling and reassembly apparatus employs a feedback-controlled electric heating oven to rapidly heat a turbine wheel while the rotor shaft is in the horizontal position. An adapter interfaces the wheel to a handling spool whose outboard end is adjusted to slide on the rotor shaft and to provide a fulcrum for supporting the wheel. A handling trolley includes a soft hydraulic system for supporting the weight of the wheel to avoid damaging the precision machined surfaces of the shrink-fit area while the wheel is being withdrawn. The handling apparatus also provides means for upending. or rotating, the removed wheel through 90 degrees to place its axis vertical for facilitating handling. A sensor system senses a radial motion of the wheel to detect clearance and to establish an appropriate fluid pressure to just balance the weight of the wheel and attached parts. The handling system includes means for rotating the wheel slightly during reassembly to align keyways or the like.

Abstract: A turbine rotor disassembly, handling and reassembly apparatus employs a feedback-controlled electric heating oven to rapidly heat a turbine wheel while the rotor shaft is in the horizontal position. An adapter interfaces the wheel to a handling spool whose outboard end is adjusted to slide on the rotor shaft and to provide a fulcrum for supporting the wheel. A handling trolley includes a soft hydraulic system for supporting the weight of the wheel to avoid damaging the precision machined surfaces of the shrink-fit area while the wheel is being withdrawn. The handling apparatus also provides means for upending, or rotating, the removed wheel through 90 degrees to place its axis vertical for facilitating handling. A sensor system senses a radial motion of the wheel to detect clearance and to establish an appropriate fluid pressure to just balance the weight of the wheel and attached parts. The handling system includes means for rotating the wheel slightly during reassembly to align keyways or the like.

Abstract: Molecular sieve material is placed in the main condensate return in vaporization-cooled transformers. The sieve material can be removed and replenished without de-energizing the transformer.

Abstract: To prevent arcing during an electrical brazing operation, the voltage drop across the brazing electrodes is sensed. When this voltage drop exceeds a predetermined threshold level due to arcing, a relay in a control circuit is picked up and its normally closed contacts open to interrupt the energization circuit for a brazing current contactor relay. The control circuit also is equipped to inhibit brazing if a discontinuity exists in its electrical connection across the electrodes. Also disclosed is a pistol grip electrical brazing tool having its electrode supporting and manipulating elements shunted from the brazing current carrying paths.

Abstract: A double lift jack employs a first hydraulic jack having a long, high-speed lift to elevate a platant into an operating position and a second hydraulic jack mounted on the platant having a short, low-speed lift. The two jacks and the platant are mounted in a sturdy, open-topped housing. The long-lift jack is employed to rapidly elevate the platant and the short-lift jack into their operating positions. The platant is thereupon affixed to the housing in the extended position using studs which are passed through a lip on the housing as the platant is elevated. A load base is raised and lowered by operation of the short-lift jack. The load base is stabilized by hardened guide rods which pass through guide holes in the platant. The thus-locked platant provides a stable base and precise guidance for positioning of a load mounted on the load base. When the studs are released, and the long-lift jack is retracted, the load base is rapidly cleared from interference with a load.

Abstract: Plural leg laminations of equal length are stacked in two groups having concealed stepped-lap joint halves at one ends and visible stepped-lap joint halves at the other ends. Plural yoke laminations of incrementally varying lengths are stacked in a first group having visible stepped-lap joint halves at each end and a second group having concealed stepped-lap joint halves at each end. A rectangular magnetic core is assembled by mating the visible joint halves of the first yoke group and the concealed joint halves of the two leg groups, and then mating the visible joint halves of the leg groups with the concealed joint halves of the second yoke group.

Abstract: Power Transformer cores are assembled by inserting a plurality of lamination inserts between the upper yoke laminations and the leg laminations in the transformer core assembly process. The arrangement allows the upper yoke to be readily removed for inserting the transformer windings over the core legs. The upper yoke is then reassembled with the inserts reinserted to complete the transformer core.

Abstract: To record significant discharges of a surge arrester, the energy dissipated in a separate varistor element equivalent to the varistor elements in the arrester and connected in the arrester discharge path is monitored. When an arrester discharge results in a temperature increase above a predetermined minimum in the separate varistor element, heat sensing means thermally coupled therewith triggers a counter to record the event.

Abstract: An elongated, insulative tube of high mechanical strength consists of resin bonded glass fibers wound in alternating helical and circumferential winding patterns. The glass fiber convolutions at the outer limits of these winding patterns embrace metallic inserts, securely captivating them within the open ends of the tube. Tapped central bores in these inserts threadedly receive end fittings adapting the tube to a transmission line supporting function. The tube also externally mounts a pair of spaced arcing rings and internally mounts a varistor array for protecting a transmission line against lightning strikes.

Abstract: A pistol grip brazing tool utilizes an insulative frame to mount a pair of elongated support elements, one fixed and the other reciprocating. The support elements, in turn, mount at their front ends a pair of electrodes in opposed relation and at their rear ends brazing cable connectors. Conductive links affixed to the support elements are adapted with interconnecting conductive cable lengths such as to conduct brazing current between the electrodes and the cable connectors in shunt relation with the support elements. The flow of brazing current is controlled to insure that brazing operations are performed without undue arcing.

Abstract: A lightning arrester of the station class is equipped with a ceramic housing protective heat shield liner formed of an ablative material capable of giving off a gas when subjected to a fault current arc. The evolved gas contributes to a rapid internal pressure buildup calculated to rupture housing end sealing diaphragms and quickly vent the arrester housing interior to prevent housing fracture. The arrester end structures are provided with expansive radial vents to accommodate unimpeded internal pressure relief.

Abstract: Transformer cores are made electrically conductive during impulse voltage condition when a certain voltage is attained by a coating of semiconductor material applied to the edges or surface of the core laminations. Under ordinary operating conditions the semiconductor material provides a high resistance path to charges in the core. Upon the occurrence of a high voltage impulse, the semiconductor material rapidly equalizes the charges in the laminations and so avoids the danger of breakdown of the insulating coatings between individual laminations.