Eaton Magnum DS Technical Data Manual - Cutler-Hammer
Technical Data
Effective: May 1998
Page
10
TD.44A.01.T.E
Cutler-Hammer
Magnum DS
Metal-Enclosed
Low-Voltage Switchgear
Application
Standards
Magnum DS circuit breakers meet or
exceed all applicable requirements of
ANSI Standards C37.13, C37.17, C37.50
and CSA.
System Voltage and Frequency
Magnum DS breakers are designed for
operation on ac systems only, 60 Hz or
50 Hz, 635 volts maximum.
Continuous Current Ratings
Unlike transformers, generators and
motors, circuit breakers are maximum-
rated devices and have no built-in
temporary overload current ratings.
Consequently, it is vital that each
application takes into consideration the
maximum anticipated current demand,
initial and future, including temporary
overloads.
The continuous rating of any Magnum
DS breaker is limited to the sensor rat-
ing, or the frame size current rating,
whichever is the lesser. For instance,
an MDS-616 1600 ampere frame
breaker with 800 ampere sensors has
a maximum continuous rating of 800
amperes, but the same breaker with
1600 ampere sensors is limited to 1600
amperes maximum.
All current ratings are based on a max-
imum ambient air temperature of 40
°C
(104
°F).
Ambient Temperature
The temperature of the air surrounding
the enclosure should be within the
limits of:
–30
° (–22°F) to +40°C (104°F).
Altitude
The breakers are applicable at their full
voltage and current ratings up to a
maximum altitude of 6600 feet (2000
meters) above sea level. When
installed at higher altitudes, the ratings
are subject to the following correction
factors in accordance with ANSI
C37.20.1:
Unusual Environmental and
Operating Conditions
Special attention should be given to
applications subject to the following
conditions:
1. Damaging or hazardous fumes,
vapors, etc.
2. Excessive or abrasive dust.
For such conditions, it is generally
recommended that the switchgear
be installed in a clean, dry room,
with filtered and/or pressurized
clean air. This method permits the
use of standard indoor switchgear
and avoids the derating effect of
non-ventilated enclosures.
3. Salt spray, excessive moisture,
dripping, etc.
Drip shields in equipment rooms
and space heaters in indoor switch-
gear, or outdoor weatherproof
enclosures, may be indicated,
depending upon the severity of the
conditions.
4. Excessively high or low ambient
temperatures.
For ambient temperatures exceed-
ing 40
°C, and based on a standard
temperature rise of 65
°C, the contin-
uous current ratings of breaker
frame sizes, and also buses, current
transformers, etc., will be subject to
a derating factor calculated from the
following formula:
105
°C Total – Special Ambient, °C
105
°C Total – 40°C Standard
Ambient
Circuit breakers are not adversely
affected by very low outdoor ambi-
ent temperatures, particularly when
energized and carrying load cur-
rents. The standard space heaters in
weatherproof switchgear will raise
the temperature slightly and prevent
condensation.
Electrical components such as relays
and instruments, however, must be
applied within the manufacturer’s
specified limits.
5. Exposure to Seismic Shock.
Magnum DS assemblies and break-
ers have been certified for applica-
tions through UBC Zone 4 and for
the California Building Code. Assem-
bly modifications are required, so
such conditions must be specified.
6. Abnormally high frequency of
operation.
In line with above, a lesser number
of operations between servicing,
and more frequent replacement of
parts, may be indicated.
Altitude Derating Factors
Altitude
Voltage
Correction
Current
Correction
Feet
Meters
6,600
2,000
1.000
1.000
7,000
2,150
0.989
0.998
7,500
2,300
0.976
0.995
8,000
2,450
0.963
0.993
8,500
2,600
0.950
0.990
9,000
2,750
0.933
0.987
9,500
2,900
0.917
0.983
10,000
3,050
0.900
0.980
10,500
3,200
0.883
0.977
11,000
3,350
0.867
0.973
11,500
3,500
0.850
0.970
12,000
3,650
0.833
0.967
12,500
3,800
0.817
0.963
13,000
3,950
0.800
0.960
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