Abstract: A protection circuit for a brushless excitation system is provided which directly monitors the output voltage of the diode bridge rectifier of the system. The protection circuit includes a reference signal generator subcircuit which provides a reference signal which tracks the dc output voltage of the diode bridge. The reference signal can vary as the system voltage is varied under certain circumstances. The protection circuit also provides for the calculation of a predetermined percentage of the reference signal voltage to create a tolerance band for testing the actual output voltage of the diode bridge rectifier. The percentage represents an acceptable limit of the ratio of a peak-to-peak ripple of the reference signal to the dc voltage of the reference signal. Using the reference signal and the percentage value to create a tolerance band, a comparator is used to test the actual output voltage of the diode bridge to determine if the output voltage is within the tolerance band.

Abstract: A segmented electromagnetic coil assembly for use in a magnetic jack type of drive mechanism used to move control rods within a nuclear reactor. The coil assembly has a plurality of individual magnetic coils spaced around and against the non-magnetic housing which contains the control rod drive shaft.

Abstract: A two-stage submersible propulsor unit comprises a shroud having a water inlet and a water outlet, a shaft assembly centrally mounted within the shroud, an upstream and a downstream propeller, each of which includes a separate hub rotatably mounted on the shaft assembly, first and second electric motors separately rotating the upstream and the downstream propellers. Each motor includes a rotor mounted around the outer periphery of one of the propellers and a stator mounted around the shroud, and first and second thrust bearing assemblies for absorbing the thrust load generated between the hubs of the first and second propellers and the shaft assembly. Both thrust bearing assemblies are contained within a housing located on the downstream end of the shaft assembly.

Abstract: A high-thrust, shock-resistant submersible propulsor unit comprises of a shroud having a water inlet and a water outlet, a shaft assembly centrally mounted within the shroud, and an upstream and a downstream propeller, each of which includes a separate hub rotatably mounted on the shaft assembly, first and second electric motors for independently rotating the upstream and the downstream propellers, wherein each motor includes a rotor mounted around the outer periphery of one of the propellers, and a stator mounted on the shroud around the rotor, and first and second bearing assemblies, each of which includes a thrust bearing disposed within the hubs of the upstream and downstream propellers in the shaft assembly, wherein the thrust bearings associated with the first and second bearing assemblies are located on opposite ends of the shaft assembly. Each of the bearing assemblies includes a removable cover which affords easy and separate access to the bearing contained in each.

Abstract: An electromagnetic projectile launcher which uses a pulsed AC generator with a power supply. The generator is operative to supply a relatively low current pulse to initially accelerate the armature after which an extremely high current pulse is applied for main acceleration. The pre-acceleration pulse may be derived from an auxiliary winding on the generator or may be provided by a relatively smaller generator operated in synchronism with the main generator or physically coupled thereto.

Abstract: The guide tube is disconnected and removed from the upper internals of the reactor to a work station in a pool of borated water. The work station includes a clamp-and-index tool, a metal-disintegration-machining (MDM) tool, pick-and-put tool, a brush tool, a nut hopper, a pin-insertion/torque tool, and a crimping tool. These tools are hydraulically operable. The clamp-and-index tool positions and, by repeated centering maintains the guide tube in precise position for removal and replacement of its split pins, the MDM burns through an old pin-and-nut assembly severing it into readily removeable fragments. This pin fragment is removed by an expeller on the clamp-and-index tool. This pick-and-put tool removes the burned nut fragment and replaces it with the new nut. The pin-insertion/torque tool inserts the new pin and torques the new nut onto the new pin. The crimping tool crimps a locking cap secured to the nut onto the pin. The tools are controlled from a command center external to the pool.

Abstract: A dynamoelectric machine's segmented baffle assembly comprises a baffle ring which is bolted to a back-up plate disposed in the stator core. The annular-shaped baffle ring is formed from a plurality of arcual segments, each segment secured by at least one of said bolts. For low flow rates of coolant gas, the air gap can be further reduced by means of a teflon insert located on the inner circumferential surface of the baffle ring. For expeditious access to the rotor assembly, only one of said segments need be.

Abstract: Laminated flux screens disposed between finger plates and end plates of a generator to reduce the axial flux striking the end region of the generator core.

Abstract: In a generator a plurality of laminations are disposed adjacent the stator teeth to extend radially outwardly from the rotor and generally perpendicular to the stator laminations to form a flux shunt to prevent fringing flux from entering the core perpendicular to the stator laminations.

Abstract: A flux sensor is provided for measuring magnetic flux in laminated cores, and especially for measuring the axial flux in the end regions of the stator cores of large generators. The sensor comprises a flat, multi-turn coil of fine wire enclosed in an insulating enclosure which includes a pressure-supporting member of greater thickness than the coil. The sensor is thin enough to be placed between the laminations of a generator core and the high clamping pressure is carried by the pressure-supporting member which protects the coil. The leads are flat conductors brought out between the laminations to the periphery of the core. Such a sensor can remain permanently embedded in the core since it does not effect the core structure.

Abstract: Disclosed is an alternating current dynamoelectric machine which has damper plates of low resistivity material over the ends of the stator's tooth region to prevent axial flux from entering the stator's core. This invention also provides for cooling of the damper plates by the inclusion of cooling ducts within the damper plates. The flow of cooling fluid through the ducts cools the damper plates and also the end region of the dynamoelectric machine.

Abstract: Disclosed is a dynamoelectric machine with a tubular shaped stator assembly having a generally cylindroid rotor assembly mounted therein. There is a clearance between the outer circumference of the rotor and the inner circumference of the stator for the passage of cooling gas. On one end of the stator assembly there is mounted a dual position air gap baffle assembly. In one position the baffle assembly will regulate the flow of cooling gas in the clearance space between the dynamoelectric machine's stator and rotor; and in the other position, there is a keystone shaped opening which will make the rotor assembly accessible.