Megger TTR310 - Page 86

M
AVTMTTR310 Rev 8 May 2016
74
4 H NAMEPLATE
VOLTAGE (L-L):
This selection is used to enter the nameplate high voltage
(H) rating of the transformer to be tested (L-L stands for
line to line). The transformer under test nameplate high
voltage is used to calculate the transformer turn ratio when
test winding 7 (H-X) or 8 (H-Y) is selected on the Main
Menu screen (see Figure 6-1). When test winding 9 CT is
selected on the Main Menu screen (see Figure 6-1), entry 4
H NAMEPLATE VOLTAGE (L-L) is replaced by 4
PRIMARY CURRENT (A), and selections 5, 6, 7, 8 of the
FULL TEST SETUP 1 screen will go off. In this case
selection 4 PRIMARY CURRENT (A) is used to enter the
nameplate primary current of a current transformer tested.
5 NO. OF H TAPS: This selection is used to enter the number of taps on the
high side (H) of the transformer to be tested. If the high
side winding does not have any taps, enter 0 (selections 6,
7, and 8 will go off.)
6 NOMINAL
VOLTAGE H TAP NO:
This selection is used to enter the tap number of the
nominal voltage of the high side (H) of the transformer.
7 HIGH VOLTAGE H
TAP NO:
This selection is used to enter the tap number of the
highest input voltage of the transformer.
8
% DIFFERENCE/TAP
This selection is used to enter the high voltage difference
(in percent) per tap. Use the following formula to calculate
this parameter:

%100
1
minmax
s
s

nV
VV
Hnameplate
HH
,
Where: n = number of H taps,
V
HMAX
= maximum voltage at H winding taps,
V
HMIN
= minimum voltage at H winding taps,
V
HNAMEPLATE
= nominal voltage at H winding taps.
If a nameplate has information on total change of voltage
in percent (for example, +/- 10% from nominal voltage),
the following formula may be used to calculate the %
difference per tap:
(Total % of voltage change)  (n – 1),
Where n = number of H taps.
Note: The aforementioned calculations are true only
if a transformer has the same voltage change per tap.
9 MAIN MENU: This selection returns you to the MAIN MENU screen,
Figure 6-1.