Key-Operated Interlocks - Siemens NXAIR M Operating Instructions Manual

21 Key-operated interlocks

21.1 Key-operated interlocks
Function and design
Key-operated interlocks are available for circuit-breaker and disconnecting panels. Access to the key of any
interlock is given with closed high-voltage door.
Key-operated interlocks allow interlocking or releasing associated operating functions depending on the state
of the operated device. Key-operated interlocks are available for the following functions:

If the withdrawable part is racked to test position, racking it to service position can be interlocked by
turning and removing the associated key.

If the feeder earthing switch is in OPEN position, switching it to CLOSED position can be interlocked
by turning and removing the associated key.

If the feeder earthing switch is in CLOSED position, switching it to OPEN position can be interlocked
by turning and removing the associated key.
The interlocked functions can be released again by reinserting the associated key, and subsequently turning
it in opposite direction.
For customization, the interlocking options are available individually and can be combined at will. When
operating the panel, it is possible to interlock two operating functions in combination: racking the
withdrawable part and changing the position of the feeder earthing switch. As the feeder earthing switch must
always be either in CLOSED position or in OPEN position, removing both associated keys simultaneously is
not possible.
A cover protects the locks against accidental access. The cover is secured on the high-voltage door with a
rotary button.
139-2021.9 / 07
HINT
Read and understand these instructions before attempting operating works.
Fig. 318: Example: High-voltage door with key-operated interlocks,
protected with cover
Key-operated interlocks
NXAIR M
(1) Cover
Rotary button to secure
(2)
the cover
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