Megger TTR310 - Page 88

M
AVTMTTR310 Rev 8 May 2016
76
3 NO. OF X TAPS: This selection is used to enter the number of taps on the
low side (X) of the transformer. If the low side winding
does not have any taps, enter 0 (selections 4, 5, and 6 will
go off).
4 NOMINAL VOLTAGE
X TAP NO:
This selection is used to enter the tap number of the
nominal output voltage of the low side (X) of the
transformer.
5 HIGH VOLTAGE X
TAP NO:
This selection is used to enter the tap number of the
highest output voltage of the transformer.
6 % DIFFERENCE/TAP This selection is used to enter the low voltage difference
(in percent) per tap. Use the following formula to
calculate this parameter:

%100
1
s
s

nV
VV
XNOMINAL
XMINXMAX
,
Where n = number of X taps,
V
XMAX
= maximum voltage at X winding taps,
V
XMIN
= minimum voltage at X winding taps,
V
XNAMEPLATE
= nominal voltage at X 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 X taps.
Note: The aforementioned calculations are true only
if a transformer has the same voltage change per tap.
7 PAUSE BETWEEN
PHASES:
For this selection, there are two choices  NO or YES.
If NO is chosen, the TTR310 will test all three windings
and display the test results as shown in Figure 6-8
(THREE PHASE TRANSFORMER TEST result
screen). If YES is chosen, the TTR310 will test the first
phase of a transformer and display the test results as
shown in Figure 6-9 (Phase A Test Result Screen).
8 SAVE CUSTOM
SETTINGS:
This selection allows you to save up to nine custom
transformer settings. See Figure 6-14, Recall (or Save)
Custom Transformer Settings Screen.
9 PREVIOUS MENU: This selection returns you to the FULL TEST SETUP 1
screen (Figure 6-7).