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Metering Formula

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Metering Formula
1. Meter Multiplier
Meter Multiplier - the multiplier applied to the register reading to obtain kilowatt-hours. M = Kh X Rr X Rs X CTR X VTR
10,000
Where ;
Kh = watt-hour constant of the meter in watt-hour per revolution
Rr = register ratio = the number of revolutions of the register worm wheel for a revolution of the first dial pointer (right hand).
Rs = gear ratio = the number of revolution of the disk for one revolution of the first point
CTR = current transformer ratio
VTR = voltage transformer ratio
Example #1:
A G.E., three phase, three wire, 120 volts, type VM-63-A, Form 5A, Class 20,
KWh meter indicates Kh of 2.4 at its nameplate and register ratio of 166-2/3 was installed at 13.2 KV wye grounded …show more content…

of the meter resulted to 11.98 rev. of the standard. g). Indicate the percent error of the above test.
h). Average accuracy of the above meter.
Solution:
Compute the Kh of the standard used
For Light Load :
Kh = 0.6 X 240 = 1.2
120
For Full Load :
Kh = 0.6 X 240 X 50 = 12
120 5
a) Compute the Light Load rev. based on the meter and standard
CR = Kh(MUT) X Rev.(MUT)
X V(std)  = 28.8 X 1 = 24
Kh(std) X No. of Element X V(MUT)
1.2 X 1
%A = Computed Rev. X 100% = 24 X 100%
Actual Rev.
24.05
%A = 99.79%
b) Compute the Light Load rev. based on the meter and standard
CR = Kh(MUT) X Rev.(MUT)
= 28.8 X 1 = 24
Kh(std) X No. of Element
1.2 X 1
%A = Computed Rev. X 100% = 24 X 100%
Actual Rev.
23.98
%A = 100.08%
c) Compute the Light Load rev. based on the meter and standard
CR = Kh(MUT) X Rev. (MUT)
= 28.8 X 2 = 24
Kh(std) X No. of Element
1.2 X 2
%A = Computed Rev. X 100% = 24 X 100%
Actual Rev.
24.04
%A = 99.83%
d) Compute the Full Load rev. based on the meter and standard
CR = Kh(MUT) X Rev. (MUT)
= 28.8 X 10 = 24
Kh(std) X No. of Element 12 X 1
%A = Computed Rev. X 100% = 24 X 100%
Actual Rev.
24.07
%A = 99.71%

6

e). Compute the Full Load rev. based on the meter and standard
CR = Kh(MUT) X Rev. (MUT)
= 28.8 X 10 = 24
Kh(std) X No. of Element 12 X 1
%A = Computed Rev. X 100% = 24 X 100%
Actual Rev.
24.08
%A = 99.67%
f). Compute the Full Load rev. based on the meter and standard
CR =

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