Siemens SENTRON 3VL160X System Manual page 298

Circuit diagrams
The contact of auxiliary contactor K1 prevents no-load operation of the molded case circuit
breaker when the undervoltage release "U<" is without power. No-load operations represent
a high level of stress for the molded case circuit breaker. If the undervoltage release is
without power, auxiliary contactor K1 has not picked up. The contact in the ON circuit
(control circuit) of the motorized operating mechanism is thus not closed, that is, the molded
case 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 1).
Circuit diagrams VL1 ... 6, motorized operating mechanism with stored energy mechanism, with or
without undervoltage release
Below are the circuit diagrams for the motorized operating mechanism with stored energy
mechanism for the circuit breakers VL160X, VL160, VL250, VL400, VL630 and VL800. The
functions of the motorized operating mechanisms are described in the following chapter:
Motorized operating mechanisms (optional) (Page 32)
S0
-F1
-F2
Figure 13-5
298
AUS
Fuse in the control circuit
Fuse in the control circuit
Motorized operating mechanism with stored energy mechanism for VL160X, VL160,
VL250, VL400, VL630 and VL800, without undervoltage release
S1 ON
PE Protective grounding
3VL IEC molded case circuit breakers
System Manual, 11/2013, 110 0110 - 02 DS 03