Abstract: A device for monitoring the leakage of cooling gas for a turbogenerator stator into the stator water-cooling system is disclosed. The device is located next to the generator so that the operative elements are at the generator storage tank operating water level. As cooling accumulates in the storage tank together with cooling water, the gas displaces the water in the leak monitor until the water level rises to a predetermined, adjustable level. When this level is reached, the gas is vented and the water level is restored to equilibrium. Each cycle is recorded on a leak trip counter. When the leakage rate exceeds a predetermined value, an alarm is triggered.

Abstract: An electronic control system to automatically determine the validity of an apparent overheating signal from an overheat monitor of a gas-cooled dynamoelectric machine and reduce machine load or indicate a monitor malfunction. Upon receipt of an apparent overheat signal by the control system, filtration of the monitored cooling gas is automatically initiated to remove pyrolysates released into the gas by overheated elements within the machine. A normal monitor response is thereby effected, provided the overheat signal is valid. If filtration of the monitored cooling gas fails to elicit a normal response within a preselected time period a monitor malfunction is indicated. The control system initiates a scheduled reduction in machine load either subsequent to validation of overheating or as verification is initiated, and if a valid indication of overloading persists, trips the excitation and remaining load from the machine.

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: 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 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.

Abstract: Certain internal parts of a gas cooled dynamoelectric machine may be coated with selected materials which will decompose at elevated temperatures to give off sub-micron particles into the machine gas coolant called pyrolysates. The presence of such pyrolysates in the machine gas coolant is indicative of localized overheating within the dynamoelectric machine. A detector is known for sensing the occurrence of these pyrolysates and hence a monitoring system has been devised for giving an early warning of machine overheating. Occasionally, oil mist particles from the machine may become entrained in the machine gas coolant and cause a false overheating signal from the detector. A second detector has been devised which may be used in combination with the first detector to provide a redundant monitoring system which will provide immediate validation of the presence of pyrolysate particles and which monitoring system is testable on line.

Abstract: An improved detector apparatus is provided in combination with a gas cooled dynamoelectric machine for detecting the presence of pyrolysate products in the machine gas coolant indictive of localized overheating of certain dynamoelectric machine parts. The detector apparatus is of the type which analyzes an ionized gas sample by measuring the current flow in the gas sample. A decrease in current flow is indicative of the presence of submicron particulates. The present invention resides in heating the gaseous sample to eliminate more volatile submicron particulates so that the output signal from the detector apparatus is indicative only of the presence of pyrolysate products resulting from the localized overheating of certain dynamoelectric machine parts.

Abstract: In a gas-cooled dynamoelectric machine, sealing means are provided at each end of the machine to prevent the axial leakage of gas coolant out of the machine along the rotor surface. One type of known seal comprises an annular holder at each end of the machine, each holder having resiliently mounted therein a pair of sealing rings spaced apart in the axial direction to define an oil feed annulus therebetween. Seal oil is supplied to the oil feed annulus at a higher pressure than the gas coolant pressure thereby sealing the gas coolant into the machine. If the gas coolant design pressure is raised so must the seal oil pressure be raised which may ultimately cause the sealing ring adjacent the ambient side of the sealing means to bind against the holder in the radial direction. The present invention is directed toward maintaining the radial mobility of shaft seals, of the type described, against pressure increases between the sealing rings.