Withstand (Proof) Tests; Figure; Withstand Test Initial Stand Time Selection Display Screen - Megger OTS 60AF Guia Del Usuario

7. If selected, the intermediate stir time between 0 seconds and 99 minutes 55 seconds may now
be set on the display. Increment to the desired time using the left and centre keys and press
SELECT.
8. If selected, the intermediate STAND TIME between 0 seconds, and 99 minutes 55 seconds may
now be set on the next display. Increment to the desired time using the left and centre keys, and
press SELECT.
9. The average start number may now be set by operating the left and centre keys.
Note:- The arrow keys increment to set the number of tests to be used in calculating the average
breakdown voltage and standard deviation. The averaging of the breakdown voltages will start
from the number set. For example, if 1 was set all the results will be used to calculate the
average. If 3 was set then the first two breakdown voltage values will be ignored when the
average is calculated.
10. Press the SELECT key to set the average start and move out of the set-up mode. The
parameters that have been set for the CUSTOM test are now displayed. Press the QUIT key to
move back to the sub display giving the option to START a test, or press QUIT again followed by
NEXT to enable another CUSTOM test sequence to be set.
Performing a CUSTOM test
1. Obtain the START option and press the key. The oil test set will now automatically perform a
sequence of individual tests according to the customised programme. The average value and
standard deviation will be given at the end, together with the options to review and print the
results.
2. Pressing the NEW key followed by the QUIT and then the MENU key is the route back to the
main menu.
There are three types of Withstand (proof) test available. Following an optional, selected stand time, the
tests subject the oil sample to a selected withstand voltage for one minute, to see if breakdown occurs.
Withstand test 'A' causes the voltage to rise to a set value, remain there for one minute and then be
removed (if breakdown does not occur beforehand).
Withstand test 'B' causes the voltage to rise to a set value, remain for one minute and then be further
increased to maximum or the breakdown point whichever occurs sooner.
BS5730 test causes the voltage to rise to 22kV, 30kV or 40kV (depending on the selected installation
category and electrode gap) for 1 minute. If breakdown occurs, another 2 tests are automatically carried
out. Both these tests must pass for the sample to be accepted.
Withstand test 'A'
1. From the main menu select the WITHSTAND option. On the display the function of the three
control keys changes to A, B and MENU. (Pressing MENU returns to the main menu options screen).
2. Press the left hand key labelled A. The display changes to appear similar to figure 15.
Figure 15. Withstand test initial stand time selection display screen.

WITHSTAND (PROOF) TESTS

INITIAL STAND TIME
00:30
ENABLED:YES
WITHSTAND A
YES/NO
SELECT
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