Megger OTS 60AF/2, User Manual

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4. When breakdown occurs (or if the maximum voltage is reached) the test voltage is cut off, the
high voltage indicator light goes out and the test set begins its oil sample stirring period. The
stirrer rotates for a period of 30 seconds and the breakdown voltage value of the previous test is
retained on the display. The display screen appears similar to figure 9.
Stirring time remaining is shown, alternating with the word ‘STIRRING’.
5. When stirring has finished the display indicates that the 30 seconds intermediate standing period
is being undertaken and time remaining is shown, alternating with the word ‘STANDING’. The
breakdown voltage is retained on the display, which appears similar to figure 10.
6. When step (5) is finished the test voltage then begins to rise again as in step (3), this time for
‘TEST 2’, and the cycle of events repeats.
7. Steps (3), (4), (5) and (6) are repeated so that the test voltage is applied for a third time. After
the test voltage has been cut off on the third test, the display shows the average breakdown
voltage value of the three tests in the sequence. The display appears similar to figure 11.
The three control keys now assume different functions. Press the left hand key labelled VIEW to
sequentially display the breakdown voltage value of each individual test, followed by their standard
deviation value. If the automatic print option is pre-selected, the results will be printed automatically at
the conclusion of a test sequence. If not, press the centre key, labelled PRINT to obtain a print-out of
the results. When the printer is in operation, the display shows ‘PRINTING PLEASE WAIT’.
Press the NEW key to return to the start of the 5 MINUTE test, followed by the left hand START key to
repeat a test sequence, or the MENU key to return to the main menu.
Figure 9. Stirring mode display screen.
Figure 10. Intermediate stand time display screen.
Figure 11. Average breakdown voltage display screen.
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Operation
XX kV
TEST 1
5 MINUTE TEST
00:30
STOP
XX kV
TEST 1
STANDING
5 MINUTE TEST
STOP
XX kV
5 MINUTE TEST
AVERAGE VOLTAGE
VIEW
PRINT
NEW