Abstract: This invention relates generally to ultrasonic inspection of welds and more particularly, to apparatus and methods for ultrasonic inspection of welds on access hole covers found in boiling water reactors having jet pumps. The apparatus includes a base, a center frame coupled to the base and projecting vertically relative to the access hole cover, a radial arm structured to rotate on the center frame and having attached thereto a first pneumatic linear thruster and a second pneumatic linear thruster, and a skew motor assembly and transducer are attached to the first pneumatic linear thruster for scanning the access hole cover weld. The skew motor assembly is structured to control the angle of the transducer and the first pneumatic linear thruster is structured to raise and lower the transducer.

Abstract: This invention relates generally to ultrasonic inspection of welds and more particularly, to apparatus and methods for ultrasonic inspection of welds on access hole covers found in boiling water reactors having jet pumps. The apparatus includes a base, a center frame coupled to the base and projecting vertically relative to the access hole cover, a radial arm structured to rotate on the center frame and having attached thereto a first pneumatic linear thruster and a second pneumatic linear thruster, and a skew motor assembly and transducer are attached to the first pneumatic linear thruster for scanning the access hole cover weld. The skew motor assembly is structured to control the angle of the transducer and the first pneumatic linear thruster is structured to raise and lower the transducer.

Abstract: A means for damping a low-friction azimuth resolver by use of an array of small magnets acting on a metallic pendulum attached to the resolver shaft. The magnetic field acts on the pendulum motion to induce a motional electromotive force and associated currents, which produce forces opposed to the motion, thereby acting as a non-contact damper on the resolver shaft. When the resolver shaft is at rest, no "eddy currents" are produced in the static magnetic field and no damping force exists. If the shaft moves, the attached pendulum cuts the magnetic flux lines and produces a drag force proportional to the shaft angular speed. The pendulum is typically made of diamagnetic material, such as lead or copper, thereby assuring that the induced forces arise solely from the motion. The magnetic field is produced by an array of small, but intense, samarium-cobalt magnets contained in a compact package providing for uniform damping throughout 360.degree. of resolver motion.