1 Feb
2011
1 Feb
'11
1:49 p.m.
It's been variously quoted as 110/220, 115/230,
117/234 and today,
120/240. ?The "standard" has crept up over the years. ?Japan, I
believe, is still 100V, although it can be either 50 or 60 Hz.
It has been 120/240 for a very long time.
Another artifact of earlier days in US industrial
applications is
55/110/220/440V 25 Hz distribution. ?The power transformers are huge
and the "hum" is more of a "rattle".
I think this is all finally gone, apart from the NorthEast Corridor.
The only reason the NEC is still 25 Hz is due to railroad
ultra-conservative engineering.
--
Will