An interesting video below on three-phase power.
Interesting issues of independent invention of two-phase power by several parties and then independent invention of of three-phase power by Tesla and Dolivo-Dobrovolsky.
Tesla patented a six-wire three-phase system. Dolivo-Dobrovolsky actually built a better three-wire system.
Fascinating. Great explanation. Thanks.
It would be interesting to trace how the influence of AEG (Dolivo-Dobrovolsky) and Westinghouse (Tesla) affected the adoption of electrical power in the territories where they dominated the market. In central Europe (AEG), three phase 380 volt power is common in the home, with 220 volts between phases. House circuits are divided between phases to balance the load. Energy-hungry appliances such as ovens, stovetops, clothes dryers, and oil furnace burners are usually 3 phase devices.
In the U.S., domestic wiring is usually the 120/240 system with high energy devices wired across the rails for 240. I suspect this is a legacy of the original Westinghouse single- or two-phase system. While three-phase is near-universal for industrial power in the U.S., it is rare in domestic installations.
Somewhat off topic, but we live in a former mining area that had one of the early two phase power systems in the early 1900s, where the phases differed by 90 degrees instead of 180 like current US domestic wiring. Here’s a Wikipedia (yeah, I know) article.
The original generation building still exists, but all the equipment is long gone and it’s currently a business incubator for the local university
For really good articles on electricity I strongly recommend amasci (dot) com.
Using Charge (…as in coulombs) he builds an excellent foundation; wish I’d known of this guy as a teenager.
Bill Beaty “gets” it.