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Equipment Description
01.4IB.77000B
PowlVac-ND® Vacuum Circuit Breaker
e. v
AcuuM
I
nterrupterS
PowlVac-ND® circuit breakers utilize sealed
vacuum interrupters to control the primary
circuit. Some vacuum interrupters appear to
be identical in size and shape externally, but
types vary in ratings due to the differences
in their internal construction. For a listing of
the vacuum interrupters used in PowlVac-ND
circuit breakers see
VACUUM INTERRUPTERS MUST BE
REPLACED ONLY WITH NEW VACUUM
INTERRUPTERS OF THE SAME PART
NUMBER.
f. v
AcuuM
I
nterrupter
c
onnectIonS
Connection to the vacuum interrupter stems is
made by means of copper contact blocks. The
top stem of the vacuum interrupter is threaded
and a copper contact block is screwed onto this
stem. The contact block is assembled to the
upper primary disconnecting devices of the
circuit breaker. Another copper contact block
with primary disconnecting devices surrounds
the bottom or moving stem of the vacuum
interrupter. The sliding contact assembly inside
the lower contact block makes contact with
this block and the moving stem of the vacuum
interrupter. The multiple parallel paths of the
sliding contact assembly keeps the current
density low.