Siemens 6SN1123-1AA00-0DA2 Configuration Manual page 219

7 Line Supply Connection
7.3 Overcurrent protective devices, transformers and main switch
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Notice
The calculated maximum short–circuit current at the connection point is an im-
portant indicator for dimensioning the required switching capacity of protective
elements, fuses/circuit breakers.
Protection elements should be dimensioned so that the maximum permissible
short–circuit current can be reliably switched by the selected protection ele-
ment.
The calculated minimum short–circuit current at the connection point is an im-
portant indicator for the maximum permissible tripping time of protection ele-
ments, fuses/circuit breakers.
Protection elements should be dimensioned so that at the minimum short–cir-
cuit current expected, these still reliably trip within the maximum permissible trip
time specified by the device manufacturer in order to guarantee protection for
personnel and avoid the risk of fire.
When connecting the machine, using a suitable measuring device (according
to DIN, EN, IEC 61557–3; VDE 0413–3) at the connection point of the drive
system, the short–circuit current should be determined and the overcurrent
protective devices installed checked to ensure that they comply with these ope-
rating conditions.
The measuring results and installed protection elements must be documented
so that they can be subsequently verified when required.
Warning
For trial operation when connected to line supplies that do not have adequate
short–circuit power (system default level), the protection elements should be
adapted so that they trip within approx. 10 ms in the case of a fault, as
otherwise there is a risk of significant damage to the device or fire.
It is not permissible to overdimension the protection elements.
Note
The recommended circuit breakers are sufficient for a maximum short–circuit
current (SCCR) < 65 kA of the drive lineup.
For line supplies that deviate from this with a smaller or higher line short–circuit
power, these can or must be appropriately re–dimensioned.
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
© Siemens AG 2012 All Rights Reserved
02.12
05.01