Excitation Graph - Omicron CT SB2 User Manual

8.6.4

Excitation graph

The excitation graph page shows the graph calculated from the test results. To display the excitation
graph, press the Excit. Graph soft key in the Excitation card. The graph shows the r.m.s. terminal/core
voltage over the r.m.s./peak current depending on the selected standard.
On the bottom right of the diagram the voltage, current and inductance values for the selected point in
the graph are displayed. The currently selected point in the graph is marked by a horizontal and a vertical
dashed line.
In this page it is possible to load the excitation graph of an already saved test from the Compact Flash
card in order to compare this graph with the one of the current test.
Figure 8-13: Excitation graph
Definition of axes in the excitation graph for different standards
Table 8-22: Definition of axes in the excitation graph
Standard
IEC 60044-1
IEC 60044-6
IEC 61869-2
IEEE C57.13
1. Calibrated to r.m.s.
Available soft keys
Table 8-23: Soft keys available for the excitation graph
Soft key Description
Moves the cursor upwards on the excitation graph.
Moves the cursor downwards on the excitation graph.
Switches off the display of values on the bottom right of the diagram. If you have
switched off the values, this soft key changes to Text On to switch the values display on
again.
OMICRON
Vertical axis
r.m.s. terminal voltage
r.m.s. e.m.f. voltage
1
average rectified terminal voltage
r.m.s. e.m.f. voltage
Test cards for Advanced CT Test mode
Horizontal axis
r.m.s. excitation current
peak excitation current
r.m.s. excitation current
r.m.s. excitation current
121