Lenze Inverter EMC - Manual (Page 10)

EMC interference injections
8
l
EDBEMV EN 1.3
4.1 Conductive coupling
U2
U1
PLC
Interference voltage
Conductive coupling is the result of several power circuits using the
same line sections.
Causes
• Frame and earth connections
• Coupling of various power circuits
• Earth loops
Countermeasures
• Short joint reference conductors
• Electrical isolation of the systems (transformer, relays ... )
4.2 Capacitive coupling
U1
Coupling current
U2
Capacitive coupling occurs due to the impact of electrical fields on
adjacent cables.
Causes
• High- voltage / signal cables
• Switching of inductances
• Parallel cable arrangement
Countermeasures
• Increase distance between cables
• Reduce parallel cable length
• Shield cables
• Reduce rate of voltage rise
4.3 Inductive coupling
U
Circuit 2
Circuit 1
Coupling inductance
I
Inductive coupling occurs due to the impact of magnetic fields on
adjacent cables.
Causes
• High-voltage current switching
• Switching of capacitances
• Parallel cable arrangement
Countermeasures
• Increase distance between cables
• Reduce parallel cable length
• Twist forward and return conductors
• Reduce rate of current rise
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