Equipotential Bonding - Siemens SINAMICS G120P Hardware Installation Manual

4.2.5

Equipotential bonding

Equipotential bonding
● Equipotential bonding within a cabinet element has to be established by means of a
● Equipotential bonding between several cabinet elements has to be established by means
● Equipotential bonding within the drive system has to be established by connecting all
Grounding and high-frequency equipotential bonding measures
The following figure illustrates all grounding and high-frequency equipotential bonding
measures using the example of a cabinet with a SINAMICS G120.
The ground connections
components.
They are made with standard, heavy-power PE conductors without special high-frequency
properties and ensure low frequency equipotential bonding as well as protection against
injury.
The connections
between the metal housings of the integrated components and the EMC shield busbar of the
cabinet. These internal connections should be made via a large area using non-isolated
metal construction components of the cabinet. In this case, the contact surface must be bare
metal and each contact area must have a minimum cross-section of several cm².
Alternatively, these connections can be made with short, finely stranded, braided copper
wires with a large cross-section (≥ 95 mm² / 000 (3/0) (-2) AWG) between the integrated
components and the EMC shield busbar.
The shield and the protective earth conductor of the motor cable provide the high-frequency
equipotential bonding between the converter and the motor terminal box.
Therefore connect the protective earth conductor and the cable shield as well to the motor
as to the converter.
Power Module PM230, IP20 / Push through
Hardware Installation Manual, 03/2012, A5E03448282B AA
suitable mounting plate (back plane), to which all metallic housings of the devices and
additional components integrated in the cabinet element (e. g. converter or line filter) are
connected. The mounting plate has to be connected to the cabinet frame and to the PE or
EMC busbar of the cabinet element with excellent electrical conductivity and a large
contact area.
of a PE busbar which runs through all the cabinet elements. In addition, the frames of the
individual cabinet elements must be screwed together multiple times with sufficient
electrical conductivity by means of special contact washers. If extremely long rows of
cabinets are installed in two groups back to back, the two PE busbars of the cabinet
groups must be connected to each other wherever possible.
electrical and mechanical drive components (transformer, cabinet, motor, gearbox, and
driven machine) to the grounding system. These connections are established by means
of standard heavy-power PE cables, which do not need to have any special high-
frequency properties. In addition to these connections, the converter (as the source of the
high-frequency interference) and all other components in each drive system (motor,
gearbox, and driven machine) must be interconnected with respect to the high-frequency
point of view. For this purpose cables with good high-frequency properties must be used.
①
②
inside the cabinet provide solid bonding for high-frequency currents
represent the conventional grounding system for the drive
Connecting
4.2 EMC compliant connection
31