Advertisement
Figure 4: Manual charging of the
closing springs
12
Note: For arc-resistant type GM-SG-AR
switchgear, if control power is not available
and the circuit breaker compartment door is
closed, the circuit breaker can be opened
manually. To open the circuit breaker
manually with the door closed, insert the
pushrod in the aperture (receptacle) in the
front door for opening the circuit breaker.
Push the rod against the open pushbutton on
the circuit breaker. The circuit breaker should
open. The circuit breaker position indicator
will change from CLOSED to OPEN, and this
change can be observed through the viewing
window included in the circuit breaker
compartment door.
2. Hold the socket-end of the crank in one
hand and the crank handle in the other
hand.
For arc-resistant type GM-SG-AR
switchgear, rotate the racking access cover
to enable insertion of the racking crank.
3. Place the socket over the end of the
racking-mechanism shaft. Align the socket
with the shoulder on the racking-
mechanism shaft.
Note: If the socket is not aligned, the socket
will not be able to engage the shoulder of the
racking-mechanism shaft.
4. Once alignment is achieved, firmly push
the crank and socket assembly toward the
racking mechanism.
5. When properly engaged, the crank should
remain connected to the racking
mechanism. If the crank does not remain
in position, adjust the spring plungers
clockwise one-half turn. This will increase
the contact pressure of the spring
plunger.
6. To remove the crank, pull the assembly
off of the racking-mechanism shaft.
Note: If the effort to rack the circuit breaker
increases considerably during racking, or if
turning of the racking crank requires
excessive force, stop racking immediately. Do
not try to force the racking crank to rotate, or
parts of the circuit breaker or racking
mechanism could be damaged. Determine
the source of the problem and correct it
before continuing with racking.
Physical inspections
1. Verify the rating of the circuit breaker is
compatible with both the system and the
switchgear.
2. Perform a visual-damage check. Clean the
circuit breaker of all dust, dirt and foreign
material.
Manual-spring charging check
1. Insert the manual-spring charging crank
into the manual-charge handle socket as
shown in Figure 4: Manual charging of
the closing spring. Turn the crank
clockwise (about 48 revolutions) until the
spring condition indicator shows the
closing spring is CHARGED.
2. Repeat the spring discharge check.
3. Verify the springs are DISCHARGED and
the circuit breaker primary contacts are
OPEN by indicator positions.
As-found and vacuum-integrity check tests
Perform and record the results of both the as-
found insulation test and the vacuum-
integrity check (dielectric) test. Procedures for
these tests are described in the Maintenance
section of this instruction manual on pages
36-52.
Advertisement
