Abstract: A diagnostic system for an electrical generator winding which has first and second passages for conduction of cooling gas. The temperature of the gas exiting the passages is determined and converted to a normalized value which may be either high, low or normal. A diagnostic computer determines the existence of predetermined combinations of high, low or normal for the two readings and these predetermined combinations are utilized by the computer which generates respective confidence factors in the existence of certain abnormal generator conditions such as open conductors, broken or blocked cooling gas passages, and sensor malfunctions, by way of example.

Abstract: This is an article and process which provide the first essentially continuous high tin flow soldering method for attaching copper based fins to copper based tubing. This invention avoids sludge buildup in the reservoir and generally avoids lead carbonate formation when the heat exchanger is in service. In addition, a novel structure is produced having a braze like joint with eta phase layers adjacent to the copper based surfaces. The invention utilizes an essentially lead free, high tin solder cascade onto a preferably cool tube, generally with a limited time of contact between the liquid solder and the tube, and with a combination air quench and wipe to remove excess solder and solidify the remaining solder. Thus a braze like joint is achieved having better heat conduction and closer thermal expansion match. This finned heat exchanger tubing is generally useful for liquid to gas type heat exchangers and especially useful for hydrogen coolers for electrical generators.