Technical specifications
6.1 Circuit diagrams
3VA molded case circuit breakers with IEC certificate
544
Manual, 03/2019, A5E03603177010-03
MO310 / MO320 motor operator actuation controlled via control cable and undervoltage
release
S0
OFF (to be provided by customer)
S1
ON (to be provided by customer)
S01 Remote command (to be provided by customer)
K1
Contactor relay (to be provided by customer)
U<
Undervoltage release (to be provided by customer)
F1
Fuse in the control circuit (to be provided by customer)
L1
Indicator light AUTO mode (to be provided by customer)
L2
Indicator light MAN mode (to be provided by customer)
This circuit is deployed in order to prevent no-load operation of the molded case circuit
breaker. The contact of auxiliary contactor K1 prevents no-load operation when the
undervoltage release "U<" is de-energized.
No-load operations subject the molded case circuit breaker to high stresses. If the
undervoltage release is de-energized, auxiliary contactor K1 has not picked up. The contact
in the ON circuit (control circuit) of the motor operator is thus not closed, i.e. the molded case
circuit breaker cannot be switched.
This auxiliary contactor is not necessary when the undervoltage release is supplied
uninterrupted (e.g. pushbutton S01) from the same source as the motor operator itself (e.g.
contact 3).