Answer / sakthivel cbe

its due to the form factor... the value of form factor is 1.11
F.F=(RMS voltage)/(avg.volatge)
the voltage in the the line is avg of sine wave we
generating. but we using RMS for our calculation...
therefore
RMS volt= Formfactor*avg voltage
RMS volt=1.11*avg volt...
thats y supply voltage are interms of multiples of 11

Answer / kuldeep

its merely a coincidence,
our earliest battery was of 2.2 v so we desined our
voltages sources by making series and parallel combination
of that batterythats why this 1.1 factor has become almost
the standard
it is also not the case with form factor
we r having 400 kv substations also bt it nthing 2 do with
11 factor

Answer / virendra

Kuldeep is exactly right , its just because of form factor
which is 1.1 so 22,33 are the multiple of 1.1

Answer / eedeepak

its just gives a easy way as we always take numeric like 10, 100, 20, 1000 for our convenience for equipments and to find its ac equivalent we have to multiply form factor which bring them down to such numbers

Answer / dhaval shah

The miss concept is Line voltage is in multiple of 11 due to Form Factor. The form factor of an alternating current waveform (signal) is the ratio of the RMS (Root Mean Square) value to the average value (mathematical mean of absolute values of all points on the waveform). In case of a sinusoidal wave, the form factor is 1.11.
The Main reason is something historical. In olden days when the electricity becomes popular, the people had a misconception that in the transmission line there would be a voltage loss of around 10%. So in order to get 100 at the load point they started sending 110 from supply side. This is the reason. It has nothing to do with form factor (1.11).
Nowadays that thought has changed and we are using 400 V instead of 440 V, or 230 V instead of 220 V.
Also alternators are now available with terminal voltages from 10.5 kV to 15.5 kV so generation in multiples of 11 does not arise. Now a days when, we have voltage correction systems, power factor improving capacitors, which can boost/correct voltage to desired level, we are using the exact voltages like 400KV in spite of 444KV

Answer / satendra

It's not the case. 230V,400V,12kV,800kV,400kV...these are
the voltages used for transmission and distribution. Aur
agar aapko lagta hai ki supply 440V hai to single phase
supply must be 254V jo ki nahi hai....and if you calclate
by 400 then it is 230 V jo ki sachchai hai...
And stop relating it to the form factor....its just a no...

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