The mention of 25Hz pumps in the last post caught my eye. The national grid runs on 60Hz (60 Cycles per Second). 25 Hertz (abbrv. Hz) (named after Physicist Heinrich Rudolf Hertz) was pioneered in some of the first commercial power generation operations starting with Nikola Tesla and George Westinghouse's Niagara Falls station in 1895. This lower frequency is better for torque but much less efficient for transformers. They require larger cores and are more expensive to make. 25Hz is not good for lighting either as it will cause flicker.
Several frequencies were tried and the overall compromise was made for 60Hz and also for 50Hz for those people wanting to avoid paying the Tesla/Westinghouse patent royalties (Europe and Japan chiefly).
A good history here: History Of Power Frequency
25Hz is still used on some railroads on the East Coast: Amtrak's 25 Hz traction power system and more here: NHRHTA New Haven RR Forum but these applications are for ancient and legacy equipment.
I am wondering just how old the pumps in New Orleans are... On one hand, if it ain't broke and things were definitely built to a higher standard back then. On the other hand, what is the up-time? The reliability? Can these pumps handle overloads? How well do they integrate into the present monitoring and control system for the City?
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