Abstract: A component maintenance system having a network linked to a data acquisition system, a data analysis system, a historical file of component design and inspection information, and a diagnostic system having the capability to perform structural analysis of discontinuities identified by the data acquisition system. The network nodes may be located apart from each other; for example in the maintenance of a nuclear power plant steam generator, the data acquisition system may be located in a high radiation area while the data analysis system is safely located away from the radiation areas. Furthermore, the diagnostic system and the file of component design and inspection history information may be centrally located and shared to support component evaluations being conducted in numerous geographic locations. Network communication facilitates the rapid evaluation of discontinuities, thereby permitting the inspection plan to be modified as the inspection results are obtained.

Abstract: An improved robotic arm system for servicing the tubesheet located within the channel head of a nuclear steam generator is provided. The system includes a robotic arm whose shoulder and elbow joints are rotatable only in the plane parallel to the tubesheet in order to eliminate the imposition of cantileverly-induced torques on the electric motors driving these joints, as well as to minimize the possibility of mechanical interference between the arm and the walls of the channel head. Each of the motorized joint assemblies of the arm includes resolvers connected not only to the output of the drive train that moves the joint, but also to the drive shaft of the electric motor that drives the drive train, wherein the feedback signal generated by the resolver connected to the drive shaft of the electric motor is the primary signal used to modulate the amount of electric power conducted to the motor of the joint. Such a configuration advantageously results in smoother robotic arm movement.

Abstract: An improved electric actuator is provided, having in association therewith a resolver. The actuator includes a stationary and a rotatable housing, and an electric motor within it. The electric motor drives the rotary housing through a speed reducing harmonic drive mechanism. The actuator has an opening in the rotary housing, and a cavity inwardly of the opening having a mating anchoring element connected with the stationary housing. A modular resolver is provided, of a shape and size to have a major portion of it occupy the cavity provided in the actuator, and having a mating part for engaging the mating part of the stationary housing, upon assemblage of the resolver to the actuator. A rotatable part of the resolver is secured to the rotary housing. A heat dissipation system is provided, including a fan mounted on a rotary member of the actuator and a closed circuit for the passage of air between the fan and a heat conductive plate forming a part of the stationary housing.