Siemens SENTRON - Special Features Regarding the Use of SIQUENCE Universal Current-Sensitive Residual Current Protective Devices (Type B and Type B+); Applications; Residual Currents at Different Fault Locations, with a Frequency Converter (FC) as an Example

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5.3
Special features regarding the use of SIQUENCE universal
current-sensitive residual current protective devices
(Type B and Type B+)
5.3.1 Applications
Typical applications that are vulnerable to smooth DC residual currents:
• Frequency converters with a three-phase connection
• Medical equipment such as X-ray equipment or CT machines
• Photovoltaic or UPS systems
• Connection points (wall boxes, charging stations) for electric vehicles
• Elevator controllers
• Pipeline trace heating
• Test setups in laboratories
• Construction sites in accordance with BGI 608 information lea et
(Electronic equipment on construction sites)
• Charging stations for battery-powered forklift trucks
• Cranes of all kinds
• Mixing plants if relevant loads are connected
• Variable-speed machine tools, such as milling and grinding machines or lathes
5.3.2 Residual currents at different fault locations, with a frequency
converter (FC) as an example
A frequency converter (FC) is considered below as a typical example of equipment
where different residual current waveforms can occur depending on the fault
location (see  gure 17).
Figure 17: Circuit with a SIQUENCE universal current-sensitive RCCB and a
frequency converter