Dynamic Balancing of Hydroelectric Units

A sensitive and convenient method for balancing hydroelectric units under operating conditions is described. This method uses electric strain gage equipment to obtain the amplitude and phase angle of the unbalance effects. The method includes trial runs with known amounts of unbalance added, and the analysis of the unbalance signals by a combined graphical and analytical procedure to determine the required balance corrections. The results obtained in balancing a machine are given to illustrate the application of the method. A method has been developed for the dynamic balancing of hydroelectric units using electric strain gage equipment. Application of this balancing procedure to the successful balancing of a number of 2-and 3-bearing machines has demonstrated that suitable unbalance data can be obtained by the use of SR-4 strain gages and that required balance corrections can be calculated from such data. This use of highly sensitive SR-4 strain gage equipment for measuring unbalance effects, together with a rational method of interpreting the data, provides a convenient means of obtaining better results in less time than was formerly realized by the cut-and-try process of balancing. Through the use of this system of balancing, many days of outage for maintenance are saved and maintenance costs are reduced substantially.