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BETA Protecting
Miniature Circuit Breakers
Configuration
1/60
Siemens ET B1 · 10/2008
1
*
You can order this quantity or a multiple thereof.
Correction factors for rated current in the case of bundling
If more than one electrical circuit is loaded in a series of miniature
circuit breakers, the resulting increase in ambient temperature
affects the characteristic curve. In this case it is necessary to
take into account an additional correction factor specific to the
rated current of the MCB.
Correction factors for rated current at different frequencies
The tripping characteristic applies to a frequency of 50 to 60 Hz.
In the case of other frequencies, the following correction factors
must be taken into account.
In the overrange, the limits of the characteristic curves correspond
to the correction factors of the thermal tripping operation. In the
case of a short-circuit, the limits of the characteristic curves
correspond to the correction factors of the magnetic tripping
operation.
In the case of direct voltage, the maximum current values corre-
spond to the frequency of 0 Hz.
Thermal tripping operation
Magnetic tripping operation
Number of MCBs
1
2 ... 3
4 ... 6
> 7
Correction factor K
1.00
0.90
0.88
0.85
Rated current
I
n
(
A)
Correction factor for
0
Hz
16 2/3
Hz
50
Hz
125
Hz
400
Hz
1000
Hz
0.3 ... 10
1
1
1
1
0.99
0.97
1 ... 40
1
1
1
0.98
0.97
0.93
50 ... 63
1
1
1
0.98
0.94
0.86
Rated current
I
n
(
A)
Correction factor for
0
Hz
16 2/3
Hz
50
Hz
125
Hz
400
Hz
1000
Hz
0.3 ... 63
1.2
1
1
1.2
1.4
1.7
© Siemens AG 2008