GE Power Break II Manual page 41

Appl icati o n
I I . Rated Service Short-Circuit Brea king Capacity (lcs)
1. Rated Service Short-Circuit Brea king Capacity:
Power Break® I I circuit breakers a re tested to com plete
a series of short-circuit interruptions with a 3-minute
rest period between i nterruptions. The breakers m ust
complete an "open" operations followed by a "close­
open" operation and another "close-open" operation.
The circuit breakers a re tested with an open circuit
voltage sufficient to enable a recovery voltage of the
rated voltage plus 5%. The 800-2000 amp Power Break I I
circuit breakers a re tested i n a 5 6,000 a m ps rms sym­
metrical, 50 Hz, 20% power factor short circuit. (See
Table 46. 11
2.
Verification of Dielectric Withstand:
Following the short-circuit interruptions, the breaker's
main circuit is verified to withstand a voltage equal to
twice its rated insulation voltage for 1 minute.
3.
Verification of Tem perature Rise:
Fol lowing the dielectric verification, a temperature-rise
test is made at the rated cu rrent and the main terminals
a re mon itored a s previously described in Sequence I test
5.
Verification of Overload Release:
4.
Following the temperature-rise verification, the circu it
breaker overload protection is verified by a pplyin g 145%
of rated current through all three poles connected in
series. The b reaker must trip within trip time cu rve.
I l l . Rated U ltimate Short-Circuit Brea king Ca pacity
(leu)
1. Verification of Overload Release:
Prior to short-circuit testing, the circuit breaker overload
protection is verified by applying 200% of rated current
through each pole individually. The b reaker must trip
with in the trip time curve.
2. Rated U ltimate Short-Circuit Breaking Capacity:
Power Break I I circuit breakers a re tested to com plete a
series of short-circuit interruptions with a 3 minute rest
period between interruptions. The breakers m ust com­
plete an "open" operation followed by a "close-open"
operation. The circuit breakers a re tested with an open
circuit voltage sufficient to enable a recovery voltage of
the rated voltage plus 5%. The 800 - 2000 amp Power
Break II circuit breakers a re tested in a 7 5 , 000 a m p rms
symmetrical 50 Hz, 20% power factor short circuit.
3.
Verification of Dielectric Withsta nd:
Following the short-circuit interru ptions, the b reaker's
main circuit is verified to withstand a voltage equal to
twice its rated insulation voltage; however, not less than
1000V for 1 minute.
4. Verification of Overload Release:
Following the dielectric verification, the circuit breaker
overload protection is verified by a pplying 250% of rated
current through each pole individua lly. The breake r m ust
trip with in the trip time curve.
IV. Rated Short-Time Withsta nd Cu rrent (lew)
1. Verification of Overload Release:
Prior to short-circuit testing, the circuit b reaker overload
protection is verified by a pplyi ng 200% of rated current
through each pole individually. The breaker must trip
within the trip time curve.
2. Rated Short-Time Withsta nd Cu rrent:
Power Break I I Circuit breakers a re tested to carry a
short-time withstand cu rrent with the overcurrent and
instantaneous over-ride protection defeated. For the
800-2000 amp Power Break II circuit breakers, a short
circuit is calibrated to deliver the equivalent I 2T of a
40,000 a m p rms symmetrical short circuit for 1 second
or 1,600,000,000 I2T. Also, the test circuit is calibrated to
reach a peak cu rrent of at least 84,000 amps d u ring its
fi rst half cycle. Since momentary contact separatio n can
occur d u ring this test, the test is made at rated voltage.
The test is performed at a frequency of 50 Hz with a plus
or minus 25% tolera nce and a 25% power factor.
3.
Verification of Temperature Rise:
Following the short-time withstand, a temperature-rise
test i s made at the rated current and the main terminals
a re monitored as p reviously described in Sequence I test
5 .
4. Short-Circuit Breaking Capacity at the Maximum
Short-Time Withstand Current:
Following the temperature verification the breakers a re
tested to com plete a series of short-circuit interruptions
with a 3-minute rest period between i nterruptions. The
breakers must complete an "open" operation followed by
a "close-open" operation. The circuit breakers a re tested
with an open circuit voltage sufficient to enable a recov­
ery voltage of the rated voltage plus 5%. The 800-2000
amp Power Break II circuit breaker is tested in a 40,000
a m p rms sym metrical, 50 Hz, 25 % short circuit.
5. Verification of Dielectric Withstand:
Following the short-ci rcuit interruptions, the breaker's
main circuit is verified to withstand a voltage equal to
twice its rated insu lation voltage for 1 minute.
6.
Verification of Overload Release:
Following the dielectric verification, the circuit breaker
overload protection is verified by a pplying 250% of rated
current through each pole individually. The breaker must
trip within the trip time curve.
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