Using Several Single-Phase Converters In Machines And Plants - Siemens SINAMICS V20 Operating Instructions Manual

4.3

Using several single-phase converters in machines and plants

Overview
Evaluate the input currents of single-phase converters in your machine or plant in terms of
harmonics and unbalance.
Description
In unfavorable cases, the harmonic currents of several converters in the neutral conductor
(N) add up to a value greater than the currents of the line conductors (L1, L2, L3). The
current carrying capacity of the neutral conductor must be sufficient for this. IEC 60364-5-
52:2019, section 524, makes recommendations for sizing the neutral conductor. If no more
precise information is available, the standard recommends dimensioning the neutral
conductor for 1.45 times the current carrying capacity of the line conductors.
Fire caused by neutral conductor (N) overload
The neutral conductor can heat up due to the load from harmonic currents and cause a fire.
• Consider the harmonic currents when dimensioning the neutral conductor.
Electric shock caused by PEN conductor overload
In TN-C supply networks, the protective function of the PEN conductor can be adversely
affected by exposure to harmonic currents.
• Consider the harmonic currents when dimensioning the PEN conductor.
SINAMICS V20 Converter
Operating Instructions, 10/2019, A5E34559884-012
4.3 Using several single-phase converters in machines and plants
CAUTION
WARNING
Electrical installation
47