Answer / pillay

It is transformer oil dielectric breakdown voltage.
A sample of the tx oil is collected and tested with a
special tester. In the tester is a pair of electrode spaced
as per BS
spec. A TEST VOLTAGE IS APPLIED ACROSS THE ELECTRODES , and
this voltage is gradually increased until a breakdown
happens resulting in sparks across the electrode, immeadetly
the test voltage is stoped and the RMS voltage is
calculated.A few test is carried over and the mean voltage
is taken as the breakdown voltage of the sample oil under
test.

It is flash point of oil.The flash point is at what temp the
oil would self ignite. This depends on the quality and type
of oil.

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