| This link should give you the required info
| Hope it helps
Maybe there should be an effort to adopt a world-wide common voltage and
wiring configuration for usage in this category now while we still can
and get it to be at least accepted for usage in the safety codes in various
countries. I propose to cut that voltage in half yet again.
So the voltage should be in the range 50 to 63.5 based on a multiple of
two ratio of the local voltage standard, 100 -> 50 in Japan, 220 -> 55
in Britain (note, half of what is mentioned now), 230 -> 57.5 in Europe,
120 -> 60 in US, 127 -> 63.5 in Mexico, etc. The secondary would be
center tapped to make half that voltage to ground on single phase (so
that range will be 25 to 31.75), and wye/star configured on three phase
for 1/1.732 of the voltage to ground (28.9 to 36.7).
So Europe would see it as 57.5/28.75 single phase, 57.5/33.2 three phase.
And USA would see it as 60.0/30.0 single phase, 60.0/34.6 three phase.
Equipment (like hand operated tools) designed for this system should be
required to function on both 50 or 60 Hz, and over the full range of
48 to 64 volts, obtained only from the 2 or 3 hot wires only, never from
the neutral (which will not be available). A grounding conductor will be
The plug/receptacle should be 2 or 3 pins enclosed in a coaxial frame
that prevents access to the pins while being inserted into the receptacle.
The coaxial frame will be a solid contact grounding conductor. A 2 pin
plug shall fit in a 3 pin receptacle at any of 3 angles, and obtain 2 of
the 3 hot legs. A 3 pin plug shall not fit in a 2 pin receptacle (where
the 3rd hole would be is thus blocked).
I envision a plug that looks somewhat like a GR-874, with 6 outer blade
serving as ground, and 2 or 3 inner pins for single or three phase. The
ground blades will be longer than the inner pins.
Ground fault protection is required to open all hot lines if any leakage
exceeding 2 milliamps total is detected (whether to the grounding conductor
or to earth ground). Any equipment trying to use the ground wire as a
neutral conductor shall trigger the ground fault interruption.
|> Could someone point me in the direction of information regarding centre
|> tapped transformers. I need more details to try and understand why they
|> used in the uk on mains voltage for controlling reduced voltage equipment.
|> I understand primary windings and that the purpose of the secondary
|> is to reduce or increase the voltage however for what reason is a
|> transformer centre tapped. As I understand it if the input voltage is
|> and the secondary winding outputs 110v and a centre tap is placed in the
|> middle of the secondary winding this will produce 55v. Question is why
|> ensure that the windings on the secondary are suffice to only produce 55v
|> and not 110v. I think I am missing a principle here.
|> Any info greatly appreciated.