Loss tests of mcnary generators

FIELD TESTS for determination of the losses of large hydroelectric generators are almost invariably made with the unwatered turbine connected to the generator shaft. The value of friction and windage losses obtained thus includes the losses of both the turbine and generator. This total value normally is apportioned between the two machines in the same ratio as their respective calculated values in accordance with AIEE Standards. For this purpose, the calculated value of turbine windage is determined by means of an empirical formula given in the American Society of Mechanical Engineers (ASME) Power Test Code. In many cases, it has been suspected that this formula yields highly inaccurate values that result in significant errors in the efficiency tests on large hydroelectric generators with Kaplan-type turbines.