Siemens SENTRON 3VL System Manual page 325

Figure 14-9
Table 14- 7
S0
S01
-F1, -F2 Control circuit fuse
PE
Note
Automatic reset/close
A separate alarm switch contact (7-8) can be connected for automatic reset after tripping. To
prevent a fault occurring in the protected circuit, automatic closing of a tripped circuit breaker
is not recommended.
The contact of auxiliary contactor K1 or K3 prevents no-load operation of the circuit breaker
when the undervoltage release "<U" is without power. No load operations represent a high
level of stress for the circuit breaker. If the undervoltage release is without power, auxiliary
contactor K1 or K3 has not picked up. The contact in the ON circuit (control circuit) of the
motorized operating mechanism is thus not closed, that is, the circuit breaker cannot be
switched.
This auxiliary contactor is not necessary in principle when the undervoltage release is
supplied uninterrupted (e.g. pushbutton S01) from the same source as the motorized
operating mechanism itself (e.g. contact 4).
3VL molded-case circuit breakers
System Manual, 03/2009, 110 0110 - 02 DS 01
Motorized operating mechanism with undervoltage release
Motorized operating mechanism for VL1250 and VL1600 wit undervoltage release
OFF (to be provided by customer) S1
Remote command
Protective grounding
ON (to be provided by customer)
K1 Auxiliary contactor
U< Undervoltage release
Circuit diagrams
325