GE Industrial Solutions BreakMaster Load Interrupter Switch - Manual (Page 15)

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5.0.3 Upper Door Interlock
The lower switch access door has a metal interlock which forces the upper door to be closed in order to close the
lower door.
5.0.4 Key Interlocking
Key interlocks are supplied when specified. Certain BreakMaster switchgear configurations require key
interlocks and they are therefore included. Standard schemes are available for locking the switch in the open
position or the closed position as well as locking the main door closed. Numerous other schemes are available for
special requirements, which can coordinate with upstream or downstream devices supplied by GE or other equip-
ment manufacturers.
5.1 Switch Operation
To manually close or open the switch, pull the release pin and rotate the handle up or down as appropriate. This
charges the compression spring, and as the spring lever goes over center, the stored energy of the spring is trans-
ferred to the shaft which snaps the switch open or closed. The blades thus move at a predetermined speed that is
independent of the operator.
The quick-make mechanism provides power to overcome blowout forces that occur if the switch is closed into a
fault. However, these forces are not transmitted to the operating handle since it is not rigidly connected to the
blades. Therefore, the switch can be safely closed under short circuit conditions within its fault-close rating.
Load interruption is accomplished by a flicker blade and engaging contact fingers located inside an arc chute. On
opening the switch, the main blades open first and all current is shunted through the spring loaded flicker blades.
Further travel of the main blades causes the flicker blades to snap out of their contact fingers where associated
arcing takes place within the arc chutes.
WARNING
Key interlocks, when supplied from the factory, will have a key for each lock;
however, for correct sequence of operation, one or more of the keys must
be eliminated. These excess keys must either be destroyed or locked away
where they will not be accessible to operating personnel.
Failure to do so may result in severe injury or death.
!
DANGER
Make sure that all power sources are deenergized before attempting any maintenance.
!
CAUTION
Operating a BreakMaster switch with a key interlock bolt extended will result
in equipment damage and may also expose a person to bodily injury or death.
The key must be inserted into the interlock and rotated to retract the locking bolt
before opertaing a BreakMaster switch.
!
BreakMaster Load Interrupter Switch