At 09:59 AM 4/10/2006 +0100, you wrote:
> > Can't remember the reason why, but the voltage between
> >2 phases (RMS Value) is the single phase RMS value * 1.732
>
>Wether it is star or delta connection, the voltage between
>any two phases will be Vrms(Sin(a) + Sin(a + (2pi/3)))
>which would look to come out to about 1.732 when a = pi/2
>(i.e. Sin(a) = 1).

Or, to put it another way, if I did this right before my first coffee..

let the line-to-neutral voltage v(t) = Vpk*sin(w*t), then the difference
between two phases will be

vd = Vpk*(sin(w*t+pi/3) - sin(w*t-pi/3))    using trig sum/diff identities
   = Vpk*(sin(w*t)*cos(*pi/3)+ cos(w*t)*sin(pi/3) - 
sin(w*t)*cos(pi/3)+cos(w*t)*sin(pi/3))
    = Vpk * cos(w*t) * K
      where K = 2 * sin(pi/3) == sqrt(3) ~= 1.73205

Vpk is peak voltage line-to-neutral
w is frequency in radians/second = 2*pi*f

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com




-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist