Monday, December 9, 2013

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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