Siemens 3VA1 100 A Manual page 497

In addition, a correction factor for setting the magnetic trip unit as a function of frequency
must be applied.
Example
Starting point:
A 3VA1 molded case circuit breaker 100 A with a TM240 trip unit is used for a 400 Hz
application. The molded case circuit breaker is required to trip instantaneously in response to
an overcurrent of 900 A.
The maximum permissible rated continuous operational current is calculated first:
100 A · 0.9 = 90 A
The setting value for instantaneous short-circuit protection (I
basis of the correction factor from the table above:
I = 900 A · 0.7 = 630 A
i
3VA molded case circuit breakers
Manual, 04/2015, A5E03603177010-02
Technical specifications
6.4 Derating and temperature compensation
) is then determined on the
i
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