Westinghouse Electric

About: Westinghouse Electric is a company organization based out in Cranberry Township, Pennsylvania, United States. It is known for research contribution in the topics: Brake & Circuit breaker. The organization has 27959 authors who have published 38036 publications receiving 523387 citations.

Production of Fast Switching Power Thyristors by Proton Irradiation

Abstract: There are several techniques currently employed by various manufacturers in the fabrication of fast switching power thyristors. Gold doping and irradiation by electron beams are among the more common ones. In all cases, the fast switching capability results from a reduction of the minority carrier lifetime of the host material by the introduction of carrier traps or recombination centers. However, accompanying this beneficial reduction in switching speed is a deleterious increase in forward voltage drop which also results from the introduction of carrier traps. Methods which minimize the voltage drop increase as the switching speed is reduced are highly desirable. One such method would achieve this by introducing the traps or recombination centers into well defined narrow regions where they will be more effective in reducing the switching speed than in increasing the forward voltage drop. Because the proton range-energy relationship in materials is relatively well defined and the lifetime reducing displacements occur near the end of their ranges, the lifetime in silicon can be reduced where desired by the precise control of proton energy. Dual energy proton beams from a tandem Van de Graaff accelerator were used in the experiments to determine whether proton beam irradiations offer advantages over other techniques. This was the subject of the present work. The results indicate that this is the preferred technique for reproducibly and rapidly processing fast switching thyristors with superior characteristics. The experimental procedure is discussed and comparisons are made with electron and neutron irradiated thyristors.

Critical Comment on a Method for Determining Electron Trap Depths

Abstract: A method proposed by Garlick and Gibson is often applied to determine the energy positions of traps in phosphors. A critical analysis of Garlick and Gibson’s method based on a mathematical determination of the applicable temperature range and on experimental evidence shows that the trap depths obtained are lower than those found by other methods. Especially the frequency-of-escape constants calculated subsequently contrast strongly to those determined by separate measurements.

Ultraviolet curable conductive resin

Abstract: A UV curable electrically conductive adhesive has been developed with low resistivity, adequate lap shear strength, good thermal stability, and very stable conductivity at high temperatures of about 100° C. and high humidity. The adhesive may be applied by silk screen printing and cured by UV in about 8 seconds. The adhesive may also be used as a replacement of solder in automated surface mount technology for electronic circuit fabrication. The adhesive is a mixture of (A) a blend of an acrylate epoxy and a urethane, a copolymer of an acrylate epoxy and a urethane, or mixtures thereof; (B) a polyfunctional acrylate monomer; (C) a photoinitiator, and (D) a conductive filler. Optionally, adhesion promoters and flow control agents may be used.

Hollow turbine blade tip closure

Abstract: An arrangement for closing selective areas of the tip portion of a hollow turbine blade having internal serpentine coolant passages is provided by radially extended wall portions at the tip of the blade along at least two sides of the outer ends of each two adjacent internal passages to be closed at the tip, retaining grooves provided in the facing surfaces of the extended wall portions, cover means overlie the outer ends of the selected adjacent passages and have opposite lateral edges received in the retaining grooves, and bond means secure the cover means along the lateral edges to the wall portions. The cover plate means preferably takes the form of two or more separable plates which can be independently inserted into the retaining grooves from an area on the tip portion of the blade which does not have the radially extended walls with retaining grooves therein.

Recuperative steam cooled gas turbine method and apparatus

Abstract: A recuperative steam cooled gas turbine in which steam used to cool the turbine section is subsequently introduced into the combustors, thereby recuperating the heat absorbed by the steam during cooling. The steam is generated in a heat recovery steam generator and then directed to a manifold within the turbine shell. From the manifold, the steam flows through passages formed within the interior of the vane by a baffle, thereby cooling the vane and heating the steam. The steam is then discharged from the vane into a chamber that collects the compressed air from the compressor. In the chamber, the heated steam mixes with the compressed air and the air/steam mixture then flows into the combustors, where it serves to reduce NOx generation from the combustors and increase power output from the turbine.