G. p
rIMAry
c
ontAct
e
roSIon
I
ndIcAtIon
In the closed position, the erosion indicator
disc (Figure 7, g) below the operating rod is
aligned with a reference arm
(Figure 7, e) on new interrupters. With
the ground and test device in the closed
position, the indicator disc after in service
fault interruptions will move upward from
alignment with the reference point due to
contact erosion. Contact erosion will decrease
the wipe which may be brought back to normal
by performing wipe adjustment. When erosion
reaches 1
/
8” (the misalignment of the indicator
disc and the reference arm with the ground
and test device closed) the interrupter should
be replaced.
If an appreciable amount (but not more than
1
/
8”) of erosion is indicated, estimate the
amount of interrupter life remaining before the
1
/
8” limit will be reached. Recheck the erosion
indicator before reaching the estimated end of
life.
Do not readjust the alignment of the erosion
indicator except when installing a new vacuum
interrupter assembly or replacing the operating
rod.
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21
Mechanical Checks and Adjustments
01.4IB.50100
