Answer / ranjan sannyasi

Many of test over an 3 phase transformer you can done, you
have to mentioned about megger test,so that test what actual
done,it's ur qsn...may i r8?
so, It's actually IR test means Insulation Resistance(IR)
test,how much insulated the transformer winding in between
their winding(primary & secondary).You could be known by
meggar test.
1.1st You have to do the PHASE TO EARTH test,how to do the
test? megger have two terminal,one of them you have to
connect with 1st phase (R-phase) or whatever(it may be
another two Y or B),must be one by one,it ds'nt matter ok,&
another with transformer body,its the earthing path.
regarding this test obtaining three of value must be
100,it's must be noted that 100 value is the accurate,if any
of value is 0 then some where in b/w winding & body it may
be leakage,for that DC current** is flowing through the
winding to earth.

2. 2nd test is the vital one.It's PHASE to PHASE TEST.It's
done by like that, suppose megger one terminal is connect R
phase and another one done by Y phase, so like that 1st R-Y,
2nd Y-B & last B-R, same you have find 3 value,like above
those.If all the value are 100 then its insulation b/w
winding are accurate,there have no insulation fault.

Answer / k.prakashchandra

With all the connections removed 1.Primary to body 2. Sec to
body 3.Between Pr and Sec .Find PI value also

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