Abstract: A gas stream monitoring system monitors a gas stream of a power generator and causes a sample of the gas stream to be collected if its characteristics indicate that a material in the power generator is being thermally degraded. After verifying that the degradation indication is true, a sample is taken of the gas stream. In order to insure that the sample is representative, an expansion chamber approximately the same size as the ionization chamber of the monitoring device is placed in line prior to the sampling device. The sampling device has three sections which collect large particles, small particulates, and vapors and gases. The products collected can be analyzed to determine which material in the power generator was thermally degraded.

Abstract: A vent plate for supporting a finger having a rivet portion is disposed intermediate adjacent core laminations in a dynamoelectric machine. A plurality of finger members secured to the vent plate cooperate with the core laminations to define a ventilation duct for circulation of a cooling gas through the core. The vent plate has a plurality of slot openings arranged to receive the rivet portions of each finger. The vent plate slots are characterized by a bow-tie outline defined by intersecting planar and curved side surfaces which permits variable orientation of rivet portions through a predetermined angular range.

Abstract: A winding conductor is provided for large dynamoelectric machines, such as turbine generators, consisting of two parallel bars each comprising two stacks of strands transposed between the stacks. The radial flux in the machine causes circulating currents with unequal distribution of current between the two parallel bars of such a conductor, causing excessive heating in one of the bars. The two bars of each conductor are, therefore, made of different cross-sectional areas substantially proportional to the different currents, so that in normal operation, the current density is the same in both bars and overheating is prevented.

Abstract: A rotor is provided for an alternating current generator carrying a superconducting field winding and having a combined damper and shield member comprising a cylindrical member of high electrical conductivity. The shield member is attached to the rotor only at the end opposite the drive shaft and is supported on the rotor at the drive end in a manner to permit relative movement between the shield and the support.

Abstract: Apparatus for sensing overheated electrical insulation through the detection of thermoparticulates in a dynamoelectric machine's cooling gas system is disclosed. The cooling gas as it circulates will entrain thermoparticulates produced in the system when there is overheating. This gaseous carrier is then withdrawn and conducted to an ionization chamber where it is ionized. Downstream from the ionization chamber there is placed a first ion collector for collecting ions with relatively small radii. A second ion collector which is biased for collecting ions with relatively large radii is also placed downstream from the ionization chamber. By comparison of ion current from the first ion collector with ion current from the second ion collector it is possible to detect the presence of thermoparticulates in the cooling gas relatively independent of gas pressure, flow rate through the monitor, and effectiveness of the radiation source.

Abstract: In a series capacitor transmission system the protective bypass device has a force firing arrangement responsive to an applied signal for causing the series capacitor bank to be bypassed rapidly, such as within three cycles, for reducing subsynchronous oscillation effects on generating equipment connected with the transmission system. A capacitive potential device supplies power to energize a firing control circuit with a pulse transformer placing high frequency or pulse voltage across the protective device for rapid bypassing. The bypass device may be a protective spark gap as is normally present for protection of the capacitor bank against overvoltages.

Abstract: An on-line apparatus and method of using particulography as a technique for detecting and locating overheated material such as insulation within a gas-cooled dynamoelectric machine is disclosed. This technique detects the presence of and identifies the origin of thermoparticulates in a gas stream which are produced by thermal degradation of materials. The gas cooling system is continuously monitored by a gas stream monitor and upon the detection of thermoparticulates in the gas stream, the gas stream is diverted through a particulate collection chamber for entrapment of a sample of the thermoparticulates. The sample is then isolated from the gas cooling system and a flow of clean gas is forced through the sample while the collection chamber is heated at a predetermined rate. Heating the collection chamber will cause reparticulation of the thermoparticulates which are carried to a gas stream monitor located downstream by the flowing gas.

Abstract: A discharge chamber seal arrangement for a water cooled turbine generator rotor. The discharge chamber seal arrangement comprises a gland seal operable during high speed operation of the rotor and a contact seal operable during low rotor speed and at standstill. A suitable control arrangement activates and deactivates the contact seal when the rotor is operating in a predetermined operational speed range.

Abstract: A system is provided for preventing overtemperature of the rotor bars of large squirrel-cage induction motors. A transmitter is mounted on the rotor and supplied with power from the rotor winding itself by a special current transformer. The transmitter is controlled by a temperature sensing element which causes it to transmit a signal in response to excessive temperature, and a slip frequency signal is also transmitted as a reliability check. A stationary receiver picks up the signal from the transmitter and includes circuitry for deenergizing the motor in response to the excessive temperature signal and for preventing energization of the motor if the slip frequency signal is not received.

Abstract: A discharge chamber seal arrangement for a water cooled turbine generator rotor. The discharge chamber seal arrangement comprises a gland seal operable during high speed operation of the rotor and a contact seal operable during low rotor speed and at standstill. Helical grooves located on the inside diameter of the gland seal develops an axial pressure gradient in the fluid annulus surrounding the shaft to reduce the leakage flow at speed through the gland seal. The helical grooves apply a pumping action which opposes the leakage flow.

Abstract: A means for controlling compressed gas and lubricant pressure in a gas storage reservoir wherein the lubricant level in the gas storage reservoir will not vary due to changes in the gas pressure.

Abstract: A method and apparatus are disclosed for the detection of incipient faults in large hydrogen-cooled dynamoelectric machines such as turbine generators. Such machines operate in a hydrogen atmosphere, for cooling, and unavoidably contain some air. The heating of organic insulation, or of metallic parts of the machine, associated with incipient faults results in oxidation or other reactions that reduce the amount of free oxygen present in the machine atmosphere. The occurrence of such incipient faults is detected by monitoring the oxygen content to detect any substantial reduction in the concentration of free oxygen. Since the amount of air in the machine may vary, it is preferred to monitor the oxygen content by determining the ratio of nitrogen to oxygen in the machine.

Abstract: Method and apparatus for accelerating a large inertia load from rest to a predetermined speed of rotation by means of a synchronous dynamoelectric machine. A synchronous dynamoelectric machine, such as a turbine generator, which is mechanically coupled to a gas turbine prime mover, is started synchronously to bring the gas turbine up to a speed which exceeds its stall speed under load. The rotor field winding of the synchronous dynamoelectric machine is connected to receive direct current excitation from a rotatable rectifier assembly of a brushless exciter. During starting, a quadrature axis winding disposed around the stator of the brushless exciter is energized by single phase alternating current. Alternating current excitation is induced by transformer action within the rotor armature winding of the exciter and is applied to the rotor field winding after being rectified by the rotatable rectifier assembly.

Abstract: A control circuit for turning on an optical isolation unit only when an input signal is at least of a given magnitude or threshold level. The circuit exhibits a resistive input below the threshold level and a constant current characteristic above the threshold. An arrangement of transistors is provided to bypass the opto-isolator below the threshold and to drive the opto-isolator with substantially constant current above the threshold.

Abstract: The temperature of a motor winding is measured or monitored by measuring the resistance of the winding. This is done by introducing a small direct current component into the motor current, which can be done by connecting an asymmetric resistance device in the motor circuit. The resistance of the motor winding can then be determined from measurements of the direct current component and the corresponding voltage. This can also be done by using a magnetic amplifier with a bias winding excited in response to the voltage of the asymmetric resistance and a control winding excited by the motor current. A signal or indication can then be obtained when the current falls below a level which indicates a resistance corresponding to an overtemperature condition.

Abstract: A spark gap assembly of a stack of insulating plates which have on one surface thereof a pair of electrodes preassembled and affixed thereto with a defined spark gap therebetween and a piece of ionizing material disposed on and affixed to each of the plates between the pair of electrodes. The plates are stacked with mating surfaces joined together and with a center plate bearing no electrodes that is joined with mating surfaces of each of two symmetrical groups of electrode bearing plates, and an electromagnetic coil is disposed around the periphery of the center plate.

Abstract: A vent plate for supporting a finger having a rivet portion is disposed intermediate adjacent core laminations in a dynamoelectric machine. A plurality of finger members secured to the vent plate cooperate with the core laminations to define a ventilation duct for circulation of a cooling gas through the core. The vent plate has a plurality of slot openings arranged to receive the rivet portions of each finger. The vent plate slots are characterized by a bow-tie outline defined by intersecting planar and curved side surfaces which permits variable orientation of rivet portions through a predetermined angular range.

Abstract: Solderable conductive strips bonded to ceramic insulator spacers interconnect terminals of adjacent substrates in a microcircuit module. Input-output connector pins are bonded to a selected base substrate and are electrically connected to the conductive strips which serve as through connecting means. Assembly and disassembly are accomplished by a reflow soldering procedure wherein hot gas is applied to the spacer-substrate interface, thereby minimizing the risk of substrate heat damage. The resulting electrical and mechanical connection is more reliable than the connection established by conventional structures having interconnecting pins since pin alignment stresses are eliminated.

Abstract: Iron or other ferromagnetic material is utilized in the magnetic circuit of dynamoelectric machines having superconductive field or excitation windings. In DC machines, a stationary salient pole field structure with a superconductive main field winding is utilized. An armature winding is wound about a smooth rotor. In AC machines, a ferromagnetic structure that encloses and rotates with a superconductive excitation winding is utilized. The ferromagnetic structure may include either salient poles interconnected by ferromagnetic shunts or a slotted or toothed rotor.

Abstract: A connector assembly for joining two half coils conductors in the form of straps are joined at one end in electrical contact with the header caps of two water cooled half coils. The unattached ends of each group of conductor straps are tinned with soft solder and interleaved with the straps of the other group. A plate is disposed on both sides of the interleaved joint and a bolt is inserted through both plates and the interleaved joint. The bolt is tightened to produce compressive union between the interleaved straps for good electrical contact. The joint is heated to coalesce the solder with the conductor straps thereby forming a metallurgical bond. The bolt is then torqued to reestablish the initial tightness to ensure a good mechanical and metallurgical joint.