A New Automatic Synchronizer

The fundamentals of automatic synchronizing are discussed, and the requirements which must be met by the ideal synchronizer are outlined. The design and the principle of operation of two different models of a newly developed automatic synchronizer are described. The paper treats the method by which, for any frequency difference within limits of present operating practise, either model of the synchronizer will cause the closing coil of the circuit breaker to be energized in advance of synchronism, by a time equal to that required to close the circuit breaker. The closing coil of the circuit breaker is, therefore, energized when the phase displacement between the voltages of the two systems to be synchronized is such that, assuming the frequency difference between the two systems remains constant during the short time required to close the breaker, the breaker contacts will always be closed at the instant of zero voltage phase displacement. The reasons for the excellent performance of these automatic synchronizers even when applied to connect systems with very erratic frequencies are outlined. A series of tests is referred to, showing the superiority of automatic synchronizing in comparison with manual synchronizing, and the results obtained with the new synchronizer models in a generating station with propeller type waterwheels are described.