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Breaking capacity and making capacity

Breaking capacity and making capacity

Breaking capacity and making capacity

(OP)
Could any one tell me the different between the terms using in shortcircuit calculation:
    1. Breaking capacity (Icu) (or Ultimate breaking capacity) vs    2. Making capacity (Icm) (or Service breaking capacity (Ics))
Thank all of you very much!

RE: Breaking capacity and making capacity

Making capacity is the maximum allowable inrush current that the breaker can withstand in a CLOSE operation without excessive contact bounce.  

Breaking capacity is the maximum fault current the breaker is capable of interrupting on an OPEN operation.

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If it is broken, fix it.  If it isn't broken, I'll soon fix that.

RE: Breaking capacity and making capacity

honglien,
The terms Icm, Ics & Icu are some parameters defined for LV circuit breakers per IEC 60947-2 used by the designer to slect appropriate circuit breaker for his application.But these terms are not used in any SC calculation method.
 

RE: Breaking capacity and making capacity

(OP)
Thank you very much!deserfox, turbingen and also kiribanda.
I agree with you, Kiribanda, they are not used in SC cal. They are specified through some type test of LVCB.

RE: Breaking capacity and making capacity

honglien

your welcome

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