Citadel 2.0 - Instruction Manual - page:
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Introduction
The Citadel circuit-breaker’s operator mechanism is employed for fixed mounted and
draw-out switchgear applications conforming to the applicable requirements of
ANSI/IEEE standards, including C37.20.2, C37.04, C37.06, C37.09 and C 37.013.
The Citadel product line is generally applied to distribution circuit breaker applications.
See manuals on Citadel - 63 - 5000 for more Generator Breaker specifics.
Mode of operation
The operating mechanism is of the stored-energy “trip-free” type.
The mechanical energy for carrying out an “open-close-open” sequence for
auto-reclosing duty is stored in the closing and tripping springs.
The charging of the closing spring is not automatically followed by the contacts
changing position. A determined closing signal must be provided for a close operation
to occur and the tripping function takes precedence over the closing function. See
ANSI / IEEE 37.04 section 6.9 for details
When the stored-energy mechanism has been charged, the mechanism is ready to
perform a closing operation.
The Citadel can now perform any of the following operating sequences;
•
Open;
•
Close;
•
Open / Close;
•
Close / Open;
•
Up to an “Open-Close-Open” sequence for auto-reclosing duty.
When a close command is given to a charged Citadel element, the energy in the
closing spring is released and forces a rotation of the breaker mechanism’s main
armature shaft. That main shaft rotation will laterally push three (3) “push rod”
assemblies that will ultimately drive the movable stem of the vacuum bottles’ moving
contact assembly into a closed (mated) position with the stationary contact assembly of
the vacuum interrupter.
During the closing operation, the opening spring takes some of the closing energy and
is itself charged.
A latching pawl falls into position and holds the opening spring assembly in a ready
position to quickly operate when called upon.
When an opening command is given, the holding pawl unlatches and the energy stored
in the opening spring and pushrod assembly contact pressure springs is released.
B R E A K E R O P E R A T I O N