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AKD-20 AR / Entellisys AR Low-voltage Switchgear
Section 8. Operating the Switchgear
Circuit Breaker Compartment Features
Key Interlocks
CAUTION: Refer to the key interlock schematic included
in the summary furnished with the equipment to determine
the sequence of operation and the correct number of
operating keys required. This precaution is necessary since
the improper use of spare keys will defeat the interlocking
scheme.
A circuit breaker key interlock is optionally available to
provide protection against unauthorized operation (Figure
8.12). The key interlock is mounted on the right on
escutcheon of the cassette below the breaker.
The typical interlock system is designed so that the key may
be removed from the lock only when the breaker is tripped.
The key actuates a cam that elevates the trip bar on the
cassette and the breaker is rendered trip free.
The operation of the key interlock should be checked as
follows:
1.
With the breaker in the CONNECTED position,
manually trip the breaker. This then allows the key
interlock to elevate the trip bar. When the trip bar is
elevated, the breaker cannot be closed but the key
can be removed. The breaker will remain trip free
until the key is returned and the trip bar is lowered.
2.
If desired, the breaker may be moved to either the
TEST or DISCONNECTED position while the key is
removed from the lock. In these positions, the
breaker cannot be operated for checking or
maintenance
53
Courtesy of NationalSwitchgear.com
Figure 8.12 Circuit breaker key interlocks
©2016 General Electric. All rights reserved.
DEH-41473
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