Lenze Inverter EMC - Manual (Page 20)

Equipotential bonding
18
L
EDBEMV EN 1.3
9 Equipotential bonding
Potential differences occur in:
z Spatially separate mounting plates within a control cabinet
z Several control cabinets spatially distributed within the system
z Use of decentralised controllers (motec/starttec)
z Components fed from different supplies
Existing potential differences cause a flow of compensating currents which amount up to several
amperes for short periods.
The effects of potential differences are as follows:
z Interference of control signals
z Interference of communication systems (error frames)
z Destruction of electronic components (e.g. interfaces)
The following measures are suitable to reduce potential differences:
z Establish equipotential bonding between mounting plates/control cabinets with the help of
large-surface large-contact earthing strip.
Fig. 10 Earthing strip for equipotential bonding
z Set up supplies with joint reference potential
z Provide large-surface shield contact surfaces
z Provide an electrical isolation (optical or isolating transformer) if above measures do not
suffice.
Fig. 11 Improving the shielding effect inside the control cabinet
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