On Thu 01 Aug 2019 at 13:06:41 (-0400), rhkra...@gmail.com wrote: > On Thursday, August 01, 2019 09:41:45 AM David Wright wrote: > > Like a real locomotive, genuine '2-phase' electrical power has one > > phase leading the other by 90°, and motors powered by it will be > > self-starting. (Steam locomotives have double-acting pistons, so they > > can choose the direction of rotation.) > > Have you ever encountered genuiine 2 phase electrical power? (Or any > multiphase power other than 3 phase?) (Just curious -- I could not instantly > think of an example.)
No—long before my time. OTOH Direct Current was still being used in a few areas of the UK when I was at college in the late 1960s, about the same time as the UK converted from town gas (H&CO) to natural gas. (Quite an upheaval for those undergoing both.) I went to a field centre in Gloucestershire in late 1971 where some of the equipment was still running on DC, and plugged in with these things: https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#UK_Walsall_Gauge_plug By this time, I believe that all domestic customers had changed over. There used to be plenty of 2-phase about, the best known example being what was the largest installation in its day: Niagara Falls. Nowadays, I see Philadelphia is one of the last places remaining. https://www.peco.com/SiteCollectionDocuments/CurrentElecTariff.pdf shows that their domestic voltages are supplied with both polarities (5-wire) whereas 2400v is just 3-wire. Cheers, David.
