Abstract: A generator seal assembly for preventing leakage of coolant in a generator is presented. The seal assembly includes a coolant side seal ring having a plurality of coolant side seal ring segments. The coolant side seal ring segment includes a seal fluid channel and radial holes circumferentially distributed along the seal fluid channel from leading edge to trailing edge through which seal fluid enters the seal fluid channel. Additional radial holes are circumferentially distributed along the seal fluid channel in a region near leading edge. Additional seal fluid enters the seal fluid channel in the region near leading edge through the additional radial holes such that pressure of seal fluid in the region is increased higher than pressure of the coolant to prevent leakage of the coolant in the region near leading edge due to ration of generator shaft.

Abstract: A hybrid power generation unit and synchronous condenser system connectable to a power grid includes a combustion turbine coupled to a first shaft and operable to provide rotational energy to the first shaft, a gear box coupled to the first shaft, and a first clutch portion coupled to the first shaft. A motor is selectively coupled to the gear box to turn the gear box and the first shaft, a second clutch portion is connected to a second shaft, and a generator is coupled to the second shaft. The generator is selectively connectable to the grid to operate as a synchronous condenser when the first clutch portion and the second clutch portion are disengaged and to convert rotational energy from the first shaft to electrical power when the first clutch portion and the second clutch portion are engaged.

Abstract: A generator seal assembly for preventing leakage of coolant in a generator is presented. The seal assembly includes a coolant side seal ring having a plurality of coolant side seal ring segments. The coolant side seal ring segment includes a seal fluid channel and radial holes circumferentially distributed along the seal fluid channel from leading edge to trailing edge through which seal fluid enters the seal fluid channel. Additional radial holes are circumferentially distributed along the seal fluid channel in a region near leading edge. Additional seal fluid enters the seal fluid channel in the region near leading edge through the additional radial holes such that pressure of seal fluid in the region is increased higher than pressure of the coolant to prevent leakage of the coolant in the region near leading edge due to ration of generator shaft.

Abstract: Controlling a shaft of a turbine generator, wherein the turbine generator includes a static excitation system and wherein the shaft is being driven in a first rotational direction at a predetermined speed. Controlling the shaft includes detecting a torsional oscillation of the shaft, calculating a control signal based on the torsional oscillation, and using the control signal, controlling an amount of power drawn by the static excitation system from the turbine generator.

Abstract: A method for controlling coupling between a first machine including a first rotating shaft having an associated first positional phase angle defined by a first shaft indicia and a second machine including a second rotating shaft having an associated second positional phase angle defined by a second shaft indicia. A rotational speed and rotational angle of the first shaft are monitored, and rotation of the second shaft is controlled by bringing the second shaft to a predetermined rotational speed relative to the first shaft speed. Acceleration of the second shaft is controlled such that the second shaft indicia is within a predetermined angle relative to the first shaft indicia upon the second shaft being brought to the predetermined rotational speed, at which point the first and second shafts are coupled such that the second shaft indicia is within the predetermined angle relative to the first shaft indicia.

Abstract: Inspecting a retaining ring of a dynamoelectric machine includes placing an optical device in a stationary component of the dynamoelectric machine and directing the optical device toward a radial view of the retaining ring. An image is obtained and transmitted of a circumferential portion of the retaining ring, using the optical device during rotation of the rotor. Identification is made of a location of one or more stress cracks forming and visible at the circumferential portion of the annular edge. Further, a structural condition is determined for at least one location on the retaining ring using a metric to identify a value of the metric exceeding a predetermined acceptable value of the metric.

Abstract: Inspecting a retaining ring of a dynamoelectric machine includes placing an optical device in a stationary component of the dynamoelectric machine and directing the optical device toward a radial view of the retaining ring. An image is obtained and transmitted of a circumferential portion of the retaining ring, using the optical device during rotation of the rotor. Identification is made of a location of one or more stress cracks forming and visible at the circumferential portion of the annular edge. Further, a structural condition is determined for at least one location on the retaining ring using a metric to identify a value of the metric exceeding a predetermined acceptable value of the metric.

Abstract: A method for controlling coupling between a first machine including a first rotating shaft having an associated first positional phase angle defined by a first shaft indicia and a second machine including a second rotating shaft having an associated second positional phase angle defined by a second shaft indicia. A rotational speed and rotational angle of the first shaft are monitored, and rotation of the second shaft is controlled by bringing the second shaft to a predetermined rotational speed relative to the first shaft speed. Acceleration of the second shaft is controlled such that the second shaft indicia is within a predetermined angle relative to the first shaft indicia upon the second shaft being brought to the predetermined rotational speed, at which point the first and second shafts are coupled such that the second shaft indicia is within the predetermined angle relative to the first shaft indicia.

Abstract: Controlling a shaft of a turbine generator, wherein the turbine generator includes a static excitation system and wherein the shaft is being driven in a first rotational direction at a predetermined speed. Controlling the shaft includes detecting a torsional oscillation of the shaft, calculating a control signal based on the torsional oscillation, and using the control signal, controlling an amount of power drawn by the static excitation system from the turbine generator.

Abstract: Apparatus for applying torsional vibration to a rotating machine is provided. In one exemplary embodiment the apparatus includes a permanent magnet machine (12) connected to the rotating machine (22) and configured to generate a three-phase AC output voltage. A converter (36) may be coupled to receive the three-phase AC output voltage from the permanent magnet machine to supply a DC load current. An electrical load (44) (or exciter) may be coupled to the converter to receive the load current. An oscillator (42) is connected to the converter to provide an oscillation signal for modulating the load current from the converter. Modulated load current causes variable loading of the permanent magnet machine thereby creating an oscillatory torque in the permanent magnet machine (12). The oscillatory torque causes torsional vibration in the rotating machine. Various components of the apparatus for applying torsional vibration may be part of a field-deployed power generating system.

Abstract: The present invention provides a method and apparatus for applying a uniformly-distributed pattern of stripes (8) on a component (6) of a large rotary machinery, such as an industrial generator. A method is provided that comprises measuring the circumferential area of the component (6) with a measuring element (14). The precise circumference is indicated and a desired number of pattern segments is determined. The circumference is divided by this number to produce equally spaced segments. This is then transferred to the rotor shaft (6) by marking on the measuring element (12) the number of segments and making a copy of the markings onto a second strip (14). These strips are then aligned on the circumferential area and cross strips (22) are placed at each of the segment marks (16). The segment areas not covered by the cross strips (24) are then painted in a color that is optically distinguishable from the non-painted regions.

Abstract: The present invention provides a method and apparatus for applying a uniformly-distributed pattern of stripes (8) on a component (6) of a large rotary machinery, such as an industrial generator. A method is provided that comprises measuring the circumferential area of the component (6) with a measuring element (14). The precise circumference is indicated and a desired number of pattern segments is determined. The circumference is divided by this number to produce equally spaced segments. This is then transferred to the rotor shaft (6) by marking on the measuring element (12) the number of segments and making a copy of the markings onto a second strip (14). These strips are then aligned on the circumferential area and cross strips (22) are placed at each of the segment marks (16). The segment areas not covered by the cross strips (24) are then painted in a color that is optically distinguishable from the non-painted regions.

Abstract: An apparatus to detect a breakdown in the insulation of a through-bolt in a laminated generator core is provided. The apparatus provides a ground detection circuit to generate and sense a signal in response to a ground that develops as a result of a breakdown in through-bolt insulation. Preferably, the circuit includes a signal source that generates a signal in response to insulation breakdown and a signal sensor to sense the signal so generated. The apparatus, moreover, can identify which among a plurality of through-bolts has experienced an insulation breakdown. Methods also are provided for detecting a breakdown in through-bolt insulation and identifying which among a plurality of through-bolts has experienced a breakdown in insulation.

Abstract: A power generator system (10) is provided having a power generator (15) and an exciter (20) for excitation of the power generator (15). The exciter (20) preferably includes a diode wheel (30). The diode wheel (30) has an a rotating support structure (31), a plurality of diodes (35) mounted to the rotating support structure (31), and a plurality of a diode support and rupture containment devices (40) each positioned adjacent a respective one of the plurality of diodes (35) to support the diode (35) and contain the diode (35) within the confines thereof in the event the diode ruptures. Each of the diode support and rupture containment devices (40) includes a pair of insulative spaced-apart containment members (42, 47) having the diode (35) positioned therebetween.

Abstract: An apparatus to detect a breakdown in the insulation of a through-bolt in a laminated generator core is provided. The apparatus provides a ground detection circuit to generate and sense a signal in response to a ground that develops as a result of a breakdown in through-bolt insulation. Preferably, the circuit includes a signal source that generates a signal in response to insulation breakdown and a signal sensor to sense the signal so generated. The apparatus, moreover, can identify which among a plurality of through-bolts has experienced an insulation breakdown. Methods also are provided for detecting a breakdown in through-bolt insulation and identifying which among a plurality of through-bolts has experienced a breakdown in insulation.

Abstract: A power generator system (10) is provided having a power generator (15) and an exciter (20) for excitation of the power generator (15). The exciter (20) preferably includes a diode wheel (30). The diode wheel (30) has an a rotating support structure (31), a plurality of diodes (35) mounted to the rotating support structure (31), and a plurality of a diode support and rupture containment devices (40) each positioned adjacent a respective one of the plurality of diodes (35) to support the diode (35) and contain the diode (35) within the confines thereof in the event the diode ruptures. Each of the diode support and rupture containment devices (40) preferably includes a pair of spaced-apart containment members (42, 47) having the diode (35) positioned therebetween. Each of the containment members (42, 47) is preferably formed of an insulating material and has a substantially annular shape to thereby define an insulative disc.

Abstract: A synchronous condenser (12) is synchronized with a power system (14) by modifying its rotational speed using a prime mover (18) while controlling the rate of change of rotational speed of the synchronous condenser (FIG. 1). With an open circuit breaker (16), the synchronous condenser (12) is brought to a rotational speed (44) close to a desired synchronizing speed (48). A clutch (20) operates between the prime mover (18) and the synchronous condenser (12) and disengages the prime mover (18) from operation once the synchronous condenser (12) is placed into operation with the power system (14). An excitation voltage is provided to the synchronization condenser (12) for providing an output voltage, which voltage is monitored. The rotational speed of the prime mover (18) is ramped at a desirable rate of change (46) for approaching an acceptable synchronizing speed (50). The rotor speed and system phase angles are monitored for bringing a desirable changing speed close to the synchronizing speed (48).