# calibration of CF and WGAIN and burden resisters

Question asked by umeshwalkar on Jan 15, 2013
Latest reply on Mar 5, 2013 by hmani

Hi fiends,

So far i am able to calculate voltage, currents, frequency.

also i worked on Watt/VA gain, RMS and Offset calibration.

now when i am freezing out my design and components.

i am confused with very stupid things.

my requirement is to design 1-PH energy meter using ADE7763.

with Meter constant = 3.2 IMP/Wh.

nominal voltage = 220 , max  voltage = 240 V

base/ref/tested current = 5 A, Imax = 15A. (CT specs = 2500:1, IP Arms = 0.25 to 20, Rb=30 Ohms, DCR=105-135, electrohms CT1232).

F= 50Hz.

while going through calibration process, i have read in ADE7763 datasheet, page 35, equation 39

"the line voltage and maximum current scale half of their respective analog input ranges. The line voltage and maximum current should not be fixed at the maximum analog inputs to account for occurrences such as spikes on the line" .

to satisfy this condition what could be then my burden resisters across CT and for Voltage divider resisters.

currently I am using 2Rb = 4.4 Ohms

and Voltage divider = 255K + 255K in series with 1K in parallel.

thanks.

Regards,

Umesh