Datasheet

US Catalog | Miniature Circuit Breakers 47
500
-500
V
U-L2
100 /div
-400
-300
-200
-100
100
200
300
400
0 6.9990.9999 1.9997 2.9996 3.9994 4.9993 5.9991
kSample499.93 Sample/div
10
-10
kA
I-L2
2 k/div
-8
-6
-4
-2
2
4
6
8
Time A Time B
Legend
Voltage
Amps
500
-500
V
U-BCP L2
100 /div
-400
-300
-200
-100
100
200
300
400
0 6.9990.9999 1.9997 2.9996 3.9994 4.9993 5.9991
kSample499.93 Sample/div
10
-10
kA
I-L2
2 k/div
-8
-6
-4
-2
2
4
6
8
Time A Time B
Legend
Voltage
Amps
Circuit breaker current limitation
Current limiting and zero crossing breakers
During the initial stages of a short circuit, a breaker’s contacts
open to interrupt the circuit. After the contacts open, an arc
forms in the air between the contacts on both the current limiting
and zero crossing breaker contacts. What distinguishes a current
limiting breaker from a zero, crossing breaker is what each
breaker does after an arc is formed between the open contacts.
A current limiting breaker “runs” the arc down the breaker arc
runner into an arc chute that extinguishes the arc.
A zero crossing breaker does not attempt to extinguish the arc.
The breaker is designed to withstand the energy of the arc long
enough for the waveform to cross zero. When the wave form
crosses zero the potential energy is zero and the arc naturally
extinguishes itself.
ABB’s current limiting breakers interrupt the arc energy in 2.3
ms to 2.5 ms ( cycle) and a zero crossing breaker allows the
arc to be present for up to 8.3 ms (½ cycle). A zero crossing
breaker will let through 100 times as much energy as an ABB
current limiting breaker.
Current limiting example
The lab test report below details a 20 A S200 series current
limiting breaker interrupting a 28 kA fault in 1.7 milliseconds.
The total “I Square T” value is 32.0 kA.
Zero crossing example
The test report below details a 20 A zero point extinguishing
breaker interrupting a 9 kA fault in 9 milliseconds. The total
“I Square T” value is 104.0 kA.