Powell Power/Vac - D. REMOTE RACKING DEVICE; E. POSITIVE INTERLOCK; F. NEGATIVE INTERLOCK

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53
Operation
01.4IB.67000
D. REMOTE RACKING DEVICE
The breaker can be racked between the
“Disconnect/Test” and “Connected” positions
electrically using the remote racking device.
Refer to Ch 3 Equipment Description I. Remote
Racking.
E. POSITIVE INTERLOCK
The positive interlock functions to prevent
racking a breaker between the “Connect” and
“Disconnect/Test” positions except when the
primary contacts are open.
The positive interlock consists of a bar which
protrudes from the left side of a closed
breaker to engage a slot in the left side racking
mechanism when the breaker is in either the
“Disconnect/Test” or “Connected” position.
When the interlock is engaged the racking
mechanism cannot be operated.
To test the function of the positive interlock
install a circuit breaker following the
instructions given in Ch 5 Operation,
B. Inserting the Removable Element Into the
Compartment. For the test the control power
circuits in the metal-clad switchgear must be
energized.
Place the breaker in the “Disconnect/Test”
position and connect the secondary disconnect
device by pulling down on the breaker handle
and horizontally inserting the lever arm fully
into the breaker to engage the secondary
disconnects. This will actuate the spring
charging motor and charge the breaker closing
springs.
The primary circuits must be deenergized
prior to performing this check.
CAUTION
Close the breaker with the control switch on
the front of the door then attempt to insert
the racking handle into the hole in the unit
door. A definite stop should be encountered,
preventing the socket on the racking handle
from engaging the racking mechanism.
The primary circuits must be deenergized
prior to performing the positive interlock
check.
CAUTION
Trip the breaker and rack it into the connected
position. Close the breaker and attempt
to insert the racking handle into the hole
in the unit door. A definite stop should be
encountered, preventing the socket on the
racking handle from engaging the racking
mechanism.
If the interlock does not function as indicated
in either of the above cases DO NOT MAKE
ANY ADJUSTMENT. Contact the nearest Powell
Service representative for instructions.
F. NEGATIVE INTERLOCK
The negative interlock functions to hold the
breaker in a mechanical and electrical trip free
mode when it is being racked between the
“Disconnect/Test” and “Connect” positions. As
an added precaution, the negative interlock
will trip the breaker and hold it trip free if
an attempt is made to operate the racking
mechanism when the breaker is closed and
in either the “Disconnect/Test” or “Connect”
position, and the positive interlock fails to
function.
The negative interlock consists of two notched
members in the left side track assembly which
operate the negative (trip latch) interlock roller
on the left side of the breaker (Figure 41). On