Abstract: The disclosure sets forth trip circuitry for a rotating shaft machine which includes redundant overspeed protection and means for testing the overspeed protection circuit while the machine remains in operation. Moreover, further protective circuitry is provided for detecting a failure in the speed sensing system. The overspeed protection and the speed sensing failure circuit are each connected to a relay system which may actuate a trip servo valve to a closed position.

Abstract: In a combined cycle power plant comprising a steam turbine and gas turbine connected through a heat recovery steam generator, the start-up mode for a steam turbine is based upon the shell metal temperature of the steam turbine. In some combined cycle plants, the output of the gas turbine is reduced so as to more closely match the output steam temperature of the heat recovery steam generator to the steam turbine metal temperature. This arrangement can be disadvantageous for several reasons and so it is proposed that a spray attemperator or desuperheater be incorporated between the heat recovery steam generator outlet and the steam turbine inlet. Moreover, control means are indicated for controlling the fluid input into the attemperator.

Abstract: The field of this invention is fluid flow control through large conduits. In particular, this invention is contemplated for use in a combined cycle power plant wherein gas turbine exhaust gas is either sent through a heat recovery steam generator (HRSG) or diverted to the atmosphere. The invention is a damper and frame assembly believed to be well suited to the purpose of channeling the hot exhaust gas within the context of a combined cycle power plant either as an isolation damper to the HRSG or a bypass damper to the exhaust stack. One key consideration is the thermal relationship between the damper blade and its adjacent frame and provision is made to provide a damper blade that will not warp and a frame wherein thermal growth and distortion are limited.

Abstract: A Moisture Separator Reheater (MSR) has a plurality of tube bundles which receive high-pressure saturated (tubeside) steam therein. Steam to be reheated (shellside steam) is passed in heat-exchange relationship with the tubes of the first and second reheater tube bundles after first being dried by the panels of a moisture separator. It emerges from the shell of the reheater dried and heated. In the reheater tube bundles saturated steam at temperatures and pressures substantially higher than the shellside steam transfers heat to the shellside steam by condensation within the tubes. The steam in the second stage tube bundle is at a temperature and pressure that is substantially higher than that of the steam in the first stage tube bundle and is heating shellside steam at a higher temperature than the shellside inlet steam to the first stage tube bundle. A greater quantity of tubeside steam than is theoretically necessary is passed through the tube bundles.

Abstract: A support arrangement is disclosed for supporting an annular diaphragm in a turbine casing. The support arrangement allows the diaphragm to be vertically aligned with respect to the turbine casing and rotor and comprises in its most basic form the combination of a horizontally mounted bifurcated lug and a vertically mounted dumbbell shaped adjusting screw.

Abstract: Apparatus is disclosed for aligning brushes of a dynamoelectric machine such as a DC generator or motor to minimize arcing of the brushes. The alignment monitor processes electrical signals from brushes of a dynamoelectric machine during tests in which various levels of buck or boost current are superimposed on a preselected level of excitation current applied to the machine, and the monitor produces output signals which, together with the levels of applied buck or boost currents, are indicative of the brushholder rigging adjustment which is required to achieve the optimum rigging position for a wide range of arc-free machine operation. Included in the brush alignment monitor are filter networks for removing noise from composite signals input to the monitor, a rectifier for changing the sign of negative signal components, and networks which amplify and integrate selected high-frequency information signals to produce output signals.

Abstract: The disclosure relates to automated drain valves for pressurized fluid conduits such as steam conduits. Recognizing that there is a direct relationship between steam temperature and steam pressure at the saturation line; the saturation line is used to derive a variable set point for an automated drain system and method. The saturation temperature is compared with the actual temperature to determine the positioning of the conduit drain valves.

Abstract: A method is presented for aligning internal turbine components, such as a packing ring holder, a rotor during assembly of the turbine. The method includes the step of inserting a plurality of proximity probes into a gap between the rotor and the packing ring holder. Thereafter, the packing ring holder is adjusted until the readouts from all probes are the same. In order to practice the method, a tool has been devised for inserting the proximity probes into the gap. The tool comprises a semi-rigid metal strip upon which the probes are spaced and mounted and further includes means for biasing the probe away from the rotor surface.

Abstract: A current/flow comparator for generating an alarm signal whenever the instantaneous flow rate of a coolant fluid cooling the armature of a dynamoelectric machine falls below a predetermined percentage of a desired instantaneous flow rate, which desired flow rate varies as a function of the square of the instantaneous current flowing through the armature, is disclosed.

Abstract: An electrohydraulic control system and method are disclosed for operating valves controlling the admission of steam to a steam turbine. The system includes a mode transfer unit for effecting a transfer between a full arc mode of valve operation to a partial arc mode of operation such that the temperature of the steam turbine varies in a controlled manner, thus permitting control of turbine stresses. Apparatus is described for generating mode flow signals, combining the signals using time ratio switching such that during a mode transfer the signals vary linearly with an admission reference factor characteristic of each mode, and generating valve lift signals from a combined flow signal using multi-slope, piecewise linear approximations to the flow-lift characteristics of the full arc mode of valve operation. The system permits mode transfers wherein total steam flow is held substantially constant and first stage turbine temperature is caused to vary linearly with admission reference factor.

Abstract: Apparatus is described for monitoring arcing of brushes used in the transfer of current signals to and from the field of a generator. Electrical signals from the brushes, which are applied to the disclosed monitor for analysis, may include brush arcing signals to be monitored and in addition high-amplitude noise spikes in the same frequency band as the brush arcing signals, the noise spikes thus masking accurate detection of low level brush arcing by conventional devices. A two-stage clipping network is provided in the monitor to raise the brush arcing/noise ratio and thus mitigate the masking effect of the noise spikes without loss of a portion of sampling interval during which arcing may occur.

Abstract: In a gas-cooled dynamoelectric machine some machine parts may contain, or may be coated with, organic materials which may undergo thermal decomposition and emit pyrolysates into the machine gas coolant upon the occurrence of localized overheating in the machine parts. These pyrolysates are detectable by means of an ion chamber detector which may be put in fluid communication with the machine gas coolant. Different pyrolysates have different characteristics and thus are identifiable by various qualitative analysis techniques making it possible to locate the source of overheating in the dynamoelectric machine by knowing which parts are coated with selected organic materials. An apparatus for collecting pyrolysates is described having a multi-media collector therein for obtaining both gaseous and particulate pyrolysates.

Abstract: A method and apparatus are disclosed for accurately determining negative sequence current in a three-phase turbine-driven generator, the currents indicative of power oscillations and of torques harmful to turbine buckets. A signal conditioner and phase-shifter network are described which provide precise amplitude and phase angle adjustments and null balancing features which permit accurate determination of the magnitude of negative sequence current even though this current is a very small quantity determined as the difference between two large signals.

Abstract: The reliability of any system can be enhanced by redundancy. In a turbomachine control system, increased reliability through redundancy is particularly desirable in view of the consequences of an unscheduled shutdown. One area of a turbomachine controls system which is particularly suited to redundant modeling is the speed control circuits. Speed pick-up probes may be subject to severe duty and are critical to the speed control of a turbomachine since they provide the speed feedback signal. The present invention is a solid state circuit which provides an output signal even if either one of two redundant speed feedback probes should fail. This circuit also allows probe replacement while the turbomachine remains in service.

Abstract: A method and apparatus are provided for measuring torsional vibrations of a rotating member by sensing passage of a plurality of circumferentially spaced elements adapted for movement with the member and for producing an electrical signal including true components representing the torsional vibrations and from which selected false components representing inhomogeneities in the elements have been eliminated.

Abstract: Austenitic alloys are disclosed which consist of iron, nickel, cobalt, chromium, aluminum, and yttrium, and articles utilizing these alloys are described such as claddings for gas turbine buckets. The substitution of selected quantities of nickel or nickel and cobalt in prior art ferrous alloys, together with the use of rather high levels of chromium, yields articles having excellent high-temperature strength, oxidation and hot corrosion resistance, and diffusion and thermal expansion compatibility with superalloy substrates.

Abstract: A reverse flow cooled dynamoelectric machine if provided with cooling gas passages extending through a fan ring and a portion of the rotor spindle to the end turns of the rotor winding in a direction substantially corresponding to the direction of flow of the cooling gas as modified by a tangential component imparted to the gas by the rotation of the fan ring. This direction is the vector sum of the longitudinal component of the velocity of the gas as it approaches the passages and the tangential component imparted by the rotation of the fan ring. The exit end of each passage is circumferentially displaced from the inlet end opposite to the direction of rotation. The centerlines of the gas passages lie in planes spaced around the axis of rotation of the rotor and parallel to this axis.

Abstract: Apparatus is described for monitoring phase currents and torsional vibrations of a turbine-generator which are indicative of the dynamic response of the machine during operation under load. The monitoring system disclosed includes probes which are operable to sense rotation of the main shaft of the turbine-generator and to feed the resulting signals to a vibration network. The vibration network eliminates from the signals any false components present at frequencies equal to multiples of the rate of rotation of the shaft and produces a composite vibration signal containing only true components of shaft torsional vibration. The composite vibration signal and a set of three phase current signals determined by stepping down, filtering, and amplifying the generator line currents are monitored continuously but recorded only when at least one of two signals derived from selected components of the composite vibration signal and phase current signals exceeds reference levels in an alarm system included in the monitor.

Abstract: An alarm system is disclosed for generating alarms when torsional oscillations of a rotating shaft exceed predetermined limits and fail to subside at a predetermined rate. The alarm system receives a torsional oscillation input signal developed by measuring the deviation of instantaneous shaft angle from a uniformly increasing value. The input signal is converted to a direct current torsional oscillation signal representative of the magnitude of oscillation. The torsional oscillation signal is compared against a first adjustable reference voltage representative of a first maximum magnitude of oscillation. A low level alarm signal is generated when the oscillation signal exceeds the first reference voltage for a predetermined length of time. The oscillation signal is also compared against a second reference voltage representative of a second maximum magnitude of oscillation. An output signal is generated when the oscillation signal exceeds the second reference voltage.

Abstract: A terminal box for a dynamoelectric machine utilizes a flux shield system wherein a plurality of flux shields are interposed between the wall of the terminal box and a high voltage bushing. Cooling fluid is passed through the flux shield system to maintain all parts at a safe, low temperature. In one embodiment of the invention, a first inner flux shield member of high electrical conductivity and low magnetic permeability is spaced from but surrounding the bushing. A second outer flux shield member of low electrical conductivity and high magnetic permeability is spaced between the first shield member and the terminal box wall. Passages and openings are provided to allow cooling fluid to circulate over the respective shield members and the wall of the terminal box without providing a path for transmission of flux from the area surrounding the bushing to the terminal box wall.