Application
Test breakers were subjected to a resonance frequency
search from 4 to 33 Hz, 2 hr. dwell at resonance, and a 211z
hr. varia ble frequency test in each of three rectilinear axes.
Tests were performed with the circuit breaker "closed" and
also "open." Vibration input during testing is described by the
graph below. Resonance G-forces during testing exceeded
3Gs. Circuit breaker contacts were monitored during testing
to verify that contacts did not open when the circuit breaker
was "closed" and did not close when the circuit breaker was
"open".
1200
Qj
LOOO
�
0.800
::; 0.600
0.400
0.200
o.ooo
5 7
9 1 1 1 3 1 5 1 7 19 2 1 2 3 2 5 2 7 29 3 1 3 3
Frequency
(Hz)
U L489 SB vibration
4G Vibration:
In addition, 800-2000A Stationary mounted
Power Break®
II
circuit breakers have been tested to with
stand 4G vibration.
Sine Sweep Vibration:
Sinusoidal log sweep vibration in each
of 3 rectilinear axes with peak acceleration of 4 G from 10 Hz
to 500 Hz, followed by 30 minute resonance dwell at the 3
most severe frequencies in each axis.
Random Vibration:
Random vibration from 2 Hz to 600 Hz
was run to the acceleration density shown below.
.q
"'
a;
� �
0.04
,g �
�
�
0.02
-e
�
0
1
2
3
10
50
100
600 1000
Frequency
(Hz)
Random vibration test spectrum
IEC Test Qualification
Power Break II circuit breakers a re tested to conform with
I EC Standard 947-2 for general purpose use with no spe
cific enclosure. Power Break II circuit breakers are designed
for intentional time delay under short-circuit conditions as
described by I EC 947-2 use category B. I n addition, Power
Break II circuit breakers are suitable for use in phase-earthed
systems and are tested in individual pole short circuits. All
Power Break I I testing is performed in open air. During short
circuit and endura nce under load testing the circuit breakers
are surrounded by a perforated metal screen. The screen is
positioned over the top of the breaker and located 4.5 inches
above the arc chamber vents. The screen also covers a sur
face located one inch away from the bottom and sides.
40
The metallic screen is made of 16-gauge steel with 3/16"
diameter holes punched on a %" stagger creating a 50%
metal-to-air ratio. During these tests, a 50 amp OPTS fuse is
used to connect the screen to the test supply neutral. Power
Break II circuit breakers a re short-circuit tested in both the
line top and line bottom configuration making them suitable
for "reverse feed" a pplications. The conformance to I EC 947-
2 consists of the following test sequences all of which have
been third-party witnessed by U L:
I. General Performance Characteristics
1. Tripping limits and Characteristics:
Power Break I I circuit breaker tripping characteristics a re
verified under short-circuit and overload conditions to
meet the relevant trip time curves. Various trip and no
trip conditions a re verified.
2. Dielectric Properties:
Power Break
II
circuit breakers a re dielectric tested
through the main circuit and the control circuits to with
stand 2500 volts for 1 minute without breaking down.
3.
Mechanical Operation and Operational
Performance Capa bility:
Power Break II circuit breakers a re endura nce tested
to 10,000 operations without maintenance. 500 opera
tions are performed under full load at rated voltage and
the remainder are performed under no-load conditions
with a minimum of 10 operations per hour. At least 10%
of the no-load operations are opened by a shunt trip
or undervoltage device. During the endurance testing
the circuit breaker is monitored to ensure the a llowable
thermal rise limits are not exceeded. I n addition to circuit
breaker endura nce, drawout breakers are racked in and
out of their substructure 100 times.
4. Verification of Dielectric Withstand:
Following the endurance test, the circuit breaker's main
circuit is verified to withstand a voltage equal to twice its
rated insulation voltage for 1 minute.
5. Verification of Tem perature Rise:
Following the dielectric verification, a temperature-rise
test is made at the rated current at a ny convenient
voltage. The breaker is connected i n open air to a power
supply through copper bus. Each main terminal is fed
by 3 each 3" x 0.25" x 3 meter long copper bus sections
h ung vertically, painted flat black and spaced 0.25"
apart. The main terminals are verified to not rise more
than
sooc
a bove ambient. The operating handle and
push-to-close button are verified to rise no more than 35
and 50°C respectively. Other areas are also verified.
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