Interlocks
139-2021.9 / 07
NXAIR M
21
7.2
Mechanical interlocks for double-busbar system
Action
Additional preconditions
Inserting the withdrawable part in the panel
Withdrawable part on the service truck
Pulling the withdrawable part out of the panel
None
Racking the withdrawable part to service position,
panel A and/or B
Withdrawable part inserted and interlocked
Low-voltage connector plugged on
High-voltage door closed
Circuit-breaker in OPEN position
Feeder earthing switch in panel A in OPEN position
Release of the actuating opening for racking the
withdrawable part by the electromagnetic interlock
from the feeder earthing switch in panel A
Plugging on the low-voltage connector
Consistent coding between connector and
withdrawable part fulfilled
Racking the withdrawable part to test position
Circuit-breaker in OPEN position
Closing the circuit-breaker
Withdrawable part in interlocked end position
(test position or service position)
Opening the circuit-breaker
None
Operating the feeder earthing switch
(panel A only)
Withdrawable part in test position
Release of the actuating opening for operating the
feeder earthing switch by the electromagnetic
interlocks from the withdrawable parts in panel A
and B
Operating the busbar earthing switch
None (see note given below)
Opening the high-voltage door
Withdrawable part in test position
Closing the high-voltage door
Low-voltage connector plugged on
7.3
Additional electromagnetic interlocks (optional)
Action
Additional preconditions
Racking the withdrawable part
General or external release
Operating the feeder earthing switch
General or external release
Operating the busbar earthing switch
General or external release