Voltech AT360, User Manual

Page: 442 / 470

S
PECIFICATIONS
P
AGE
8-18 V
OLTECH
AT
I
U
SER
M
ANUAL
8.2.11 GBAL T
EST
The accuracy is based on the test conditions chosen to measure the
longitudinal balance of the transformer under test, and is given as:
Where
A
T
is the total accuracy (dB)
A
R
is the basic relative accuracy (dB)
A
C
is the correction for calibration
A
VX
is the correction for the X measurement voltage level
A
VY
is the correction for the Y measurement voltage level
The value of
A
R
is given in the table in section 8.1 of this chapter
The values of the other factors are given below.
Where
F
M
is the measurement frequency (Hz)
V
MX
is the measured voltage for the
X
measurement (V)
V
MY
is the measured voltage for the
Y
measurement (V)
∆
V
CMNX
is the error due to the common mode voltage in the X
measurement
∆
V
CMNY
is the error due to the common mode voltage in the Y
measurement
The error due to the common mode voltage in the measurement (
∆
V
CMNX
and
∆
V
CMNY
) is given as
Where
V
CMN
is the common mode voltage measured
A =
C
0.1 + (0.0000001% )
x
F
M
A = A
T R C VX VY
+0.87(A +A +A )
∆
V = V
CMN
CMN M
* 1+ (0.00000001 / 398
x
F )
2