Blocking Magnet purpose in HV SF6 circuit breaker

[ekuegler]

Can anyone explain the purpose of a blocking magnet within a 11kV ABB SF6 circuit breaker, what is it's function. Circuit breaker is motor charged with 1x shunt trip, 1x closing coil and a blocking magnet.

Thanks for your help

 

[slavag]

Not only in ABB.
Block magnet or lock magnet, additional coil, is used for block mechanical/handle close of Circuit Breaker.

 

[RRaghunath]

Blocking magnet in indoor switchgear is generally for interlocking function such as to prevent withdrawing the breaker when it is in 'ON' condition etc.

 

[slavag]

Raghun.
Such type of interlock is mechanical only.
If you need some additional interlocks ( station interlocks for example), you have add block magnet for truck or for earthing switch.