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Circuit breaker accessories - Service releases
Shunt opening release
This allows circuit-breaker opening by
means of an electric command. Release
operation is guaranteed for a voltage
between 70% and 110% of the rated
power supply voltage Un, both in AC and
in DC. It is always fitted with an auxiliary
limit contact.
Under voltage release
This opens the circuit-breaker due to a
power supply failure to the release, or
voltage drops to minimum values of 0.7
x Un with a trip range from 0.7 to 0.35 x Un.
After tripping, the circuit-breaker can be
closed again, starting with a voltage
higher than 0.85 x Un. With the undervoltage
release de-energised, neither
circuit-breaker nor main contact closure
is possible.
Time-delayed undervoltage release
The undervoltage release can be combined
with an external electronic power
supply time-delay device, which allows
circuit-breaker opening to be delayed in
the case of a power cut to the release
itself, according to fixed time-delays of
0.5-1-2-3 [s], so as to avoid unwarranted
trips caused by temporary malfunctions.
It is available for the SACE S3, S4, S5,
S6, and S7 circuit-breakers with power
supply voltages at 110-220 V (50-60 Hz)
only coupled with an undervoltage release
at 310 V DC.
Shunt closing release
This allows circuit-breaker closure by
means of an electric command. Operation
of the release is guaranteed for a
voltage between 80% and 110% of the
rated power supply voltage Un, both in
AC and in DC.
ABB SASE
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