The latter can closed
only the first and third are open
C THREE unit supplies and bus-tie. Three supplies
(generators transformers) the same
busbar for which parallel operation is
not allowed
only one the three circuit-breakers can
be closed
10.3 parts
The spare parts available are:
- Shields and front escutcheon plate
- Opening solenoid for the PR122/DC-PR123/DC overcurrent release
- Arcing chamber
- Closing springs
- Clamp-type isolating contact for fixed part the withdrawable circuit-breaker
- Sliding earth contact (for withdrawable version)
- Fixed part shutters
- Operating mechanism
- Transparent protection for PR122/DC and PR123/DC releases
- SACE PR030/B power supply unit
- Tool case
- Front escutcheon plate for Ronis-type key lock
For further details, ask for the ABB SACE spare parts catalogue.
Model 3447 Apparatus Emax cale
D oc-N 1SDH000635R0002
Page No.
27/108
.Table feasible mechanical interlocks between two three circuit-breakers
Type of
interlocks
Number of
circuit-breakers
Type circuit-breaker Possible interlocks
A TWO normal power supply unit
and emergency unit
the first circuit-breaker can closed only if
the second (emergency) breaker open
B THREE two normal power supply units and
an emergency unit
the first and third circuit-breakers can be
closed only the second (emergency)
breaker open.
The two half-busbars can supplied
by single transformer (bus-tie closed)
or simultaneously both
(bus-tie open)
one two circuit-breakers out three can
be closed the same time
D THREE unit supplies single
closed circuit-breaker
