15
I N SER T I O N A N D R EM OVA L , I N T ER LO C K S
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Interlocks
The ADVAC® 38 kV circuit breaker contains a
number of interlocks. A description of each
interlock follows as encountered during racking
of the breaker into the breaker compartment.
Modification to interlocks can result in hazardous
conditions to personnel and equipment. Do NOT
override, bypass or adjust interlocks.
Interference blocking
An interference plate in the breaker compartment
prevents under-rated breakers from being inserted
into higher-rated compartments. The interference
plate rating includes continuous current,
interrupting current, close and latch capability
and maximum voltage. Breakers with the same
or higher interference plate rating can be inserted
into a compartment of equal or lower value.
Positive position for racking
The racking mechanism is blocked unless
the interlock tabs are fully extended into
the compartment slots.
Positive position for removal
The handle release pin prevents withdrawing
the breaker from the compartment by blocking
withdrawal of the locking tabs. The handle release
pin blocks the handles unless the breaker is in the
disconnect position.
The closing spring may be manually recharged in
the disconnect and withdrawn positions. Verify
that the breaker is open and the closing spring
is discharged before removing the breaker from
the cell.
Spring charged
This maintenance interlock prevents breaker
removal from the compartment until the closing
spring has been manually discharged in the
disconnected position. To perform discharge, press
the breaker close button and then press the breaker
open button to cycle the breaker through a close
and then open operation.
Position interlocks
The position release lever must be depressed to
begin racking the breaker in any direction from
any positive position (disconnect, test or connect).
The release lever is blocked from actuation when
the breaker is closed. The ability to close the
breaker is blocked unless the breaker is in one
of the three positive positions.
The ADVAC 38 kV EL model 4 closing spring must
be manually discharged before the breaker can
be removed from the cell. This can be accomplished
by closing and opening the breaker while it is in the
disconnect position.
If the circuit breaker is closed in the disconnected
position and the closing springs are discharged,
the breaker will open if an attempt is made to
remove the breaker.
