Voltech AT3600 - Page 378

SPECIFICATION VOLTECH AT3600 USER MANUAL
PAGE 8.1.20. VPN 98 - 024 SPECIFICATION
GBAL TEST
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 1.1 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
CVXV
Y
+0.87(A +A +A )
∆ V = V
CMN
CMN M
* 1+ 0.00000001 / 398 x F
2