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Entry type: FAQ Entry ID: 109780013, Entry date: 05/12/2020

SINAMICS: Information on error loop impedance according to IEC 60204-1

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The inverters include electronic short-circuit protection and thus meet the requirements for automatic shutdown in the event of an error.

No further measurements need to be made in the motor circuits. The loop impedance measurement is therefore only carried out on the mains side of the drive system.  

In the case of a modular drive system, the measurement shall be carried out at the terminals of the first component "behind" the overcurrent protection device. 

Requirements of IEC 60204-1 
In Chapter 18.2, IEC 60204-1 lists the conditions to be checked for protection by an automatically shutting down the power supply. This test consists of two parts:
  1. Checking the continuity of the protective conductor circuits
  2. Checking the fault loop impedance and the suitability of the associated overcurrent protection device

According to Chapter 18.2.3, the error loop impedance can be calculated or measured.

Siemens provides the relevant information for its frequency inverters in article  103474993.

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