Mystery History Answers (April, 2015)

(ca. 1936)^ - J. A. Griffitts opening the circuit breaker on the last DWP 50 cycle circuit.  Taken in the old control house at RS-C in Wilmington.  


Historical Notes

Prior to 1936, the Southland was sort of an electrical enclave. Both Edison and Los Angeles Bureau of Power and Light generated and distributed their power at 50hz where most parts of the country were at 60hz. Some electrical appliances worked at both frequencies, but for frequency-sensitive products manufacturers created special 50hz models just for the Southern California market. And when newcomers moved from outside the region, they paid to have their old devices converted, or simply bought new ones that would work on the 50hz grid.

In 1936, in order to accept power from Hoover Dam's 60hz generators, the Los Angeles Bureau of Power and Light converted its entire system from 50 to 60hz. 

It would take Southern California Edison another 12 years (1948) before they would also convert to 60hz.*



(1936)^^ - View showing the Frequency Changer at RS-C in Wilmington.  


Historical Notes

This machine was basically two synchronous condensers, one wound for 50 cycles and the other for 60, mechanically coupled and operating in a single hydrogen-filled shell.  This unit was installed in preparation for the BP&L 60 cycle cutover to allow a connection between the Bureau's 60 cycle system and Southern California Edison's 50 cycle system.  After Edison's conversion to 60 cycles, the 60 cycle unit stayed at RS-C to become Condenser C and the 50 cycle unit was moved to Receiving Station D to become Condenser B.  The unit was water-cooled and the cooling towers were located in an underground vault.  The vents for the cooling towers are in the structure at the left edge of the picture.^



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References and Credits

^DWP - Water and Power Associates Historical Archives - Courtesy of Rex Atwell

* LA's Power Grid



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