GE Industrial Solutions AKD-20 Low Voltage Switchgear - Manuel (Page 52)

AKD-20 Low-voltage Switchgear
Chapter 7. Operating the Switchgear
52 ©2012 General Electric All Rights Reserved
7-1 Circuit Breaker Operation
General
Included below are abbreviated operating instructions for
Entelliguard G circuit breakers. Before activation of the circuit
breakers or operation of the switchgear equipment, thoroughly
read, and be familiar with the circuit breaker manuals which will
be supplied as supplementary information to this manual.
Publication number is: DEH-41304.
Manually Operated Breakers
Closing Manually Operated Entelliguard G Circuit
Breakers
Manually operated Entelliguard G circuit breakers are equipped
with a integral charging handle and a push button marked CLOSE
on the front of the escutcheon. The spring must be charged first.
1. A complete charge is accomplished by pulling the handle
down about 90° (until it stops) ten times to fully charge the
closing springs. This will not close the breaker contacts. The
charge indicator will show CHARGED on a yellow
background.
Tripping Manually Operated Entelliguard G Breakers
A mechanically operated OPEN button mounted on the breaker
escutcheon, operates the trip shaft to open the breaker.
Electrically Operated Breakers
Electrically operated breakers may be closed by ac control power,
or dc (normally station or standby battery) control power. Refer to
the provided elementary diagrams for information on control
circuitry.
The breakers may be controlled by a mechanically operated,
double insulated push-button switch on the breaker escutcheon,
by a breaker control switch, or by a relay contact. The control
switch or relays may be located in the equipment which houses
the breaker, or may be installed in a remote location. Fuses are
located on the instrument panel just above the breaker
compartment.
Electrical Tripping on Entelliguard G Breakers
Circuit
A shunt trip device is used for electrical tripping and each breaker
can have up to two shunt trip accessories installed.
7-2 Circuit Breaker Drawout
Operation
Breaker Positions
Refer to Fig. 7-1. The drawout operation features four positions:
1. CONNECTED - In the CONNECTED position, the primary and
secondary disconnects are fully engaged. The breaker must
be tripped before it can be racked out of this position.
2. TEST - When in the TEST position, the primary contacts are
disconnected, but the secondary contacts remain engaged.
This allows complete breaker operation without energizing
the primary circuit.
3. DISCONNECTED - In the DISCONNECTED position, neither
primary or secondary contacts are made. Breakers may be
racked between these three positions with the
compartment door closed and latched.
4. WITHDRAWN - With the door open, the breaker can be
rolled out manually from the DISCONNECTED to the
WITHDRAWN position. Here, the breaker is completely out
of its compartment, ready for removal.
Fig. 7-1. Entelliguard G switchgear circuit breaker
shown in DISCONNECTED position
Drawout Operation
All breakers are supported on the drawout rails mounted on the
side walls of the cassette. On Entelliguard G breakers, two wheels
on each side of the breaker rest on each drawout rail.
Motion is provided by a mechanism mounted on the bottom of the
cassette. This mechanism drives racking cams which engage pins
anchored to each side of the breaker.
The cams are driven by a removable racking handle or remote
racker which engages the mechanism. The handle is inserted
through an opening in the cassette escutcheon below the breaker.
Turning the handle in a clockwise direction drives the breaker into
the compartment. As the breaker disconnect fingers engage the
stab tips, a high force will be felt. Turn the racking handle until the
indictor barrel clearly shows CONNECTED.
The position of the breaker is given by the position indicator in the
cassette escutcheon as it moves through the door cutout.