Electrical machinery tests and specifications based on modern standards

Comparisons are made of the standardization rules for electrical machinery now in force in various countries. It is shown that the differences are of a very minor character and that machinery built in conformance with the American rules will usually also conform with the rules employed in other countries. The suggestion is made that 55 degrees could be employed as the ambient temperature of reference for tropical ratings and it is maintained that such a plan fits in nicely with the value of 40 degrees already adopted as the ambient temperature of reference for other than tropical ratings. Attention is called to a series of acceptance tests on some large waterwheel generators and to the temperature results obtained by making cyclic heat runs on these machines.