Power Wiring
ANCA Motion
D-000129 Rev 09
65
5
5.5
Installations Conforming to the EMC Directive
EMC stands for Electromagnetic compatibility. It is the ability of electrical/electronic equipment to operate without
problems within an electromagnetic environment. The equipment must not disturb or interfere with any other
product or system within its locality. Variable speed drives are a source of interference, and all parts which are in
electrical or airborne connection within the power drive system (PDS) are part of the EMC compliance defined by
EN 61800-3:2004
. See 10.8.2.1 European EMC Directive EN 61800-3
The drive interference is generated from the output voltage waveform which is a rapidly changing voltage
waveform (Pulse Width Modulation). The voltage transitions present on all motor cables and motor windings
induce parasitic common mode currents (I
LEAK
) in the stray capacitance of the motor and cable system. See
Figure 5-5: Common Mode Noise Current Paths in a Drive
The common mode currents return to the
drive inverter by the lowest available impedance paths which must be carefully managed to prevent interference
voltages being generated in other equipment connected to the same earth system. The internal common mode
capacitors of the drive provide one return path (I
DC
) to the drive, and the EMI line filter provides another return
path I
LF
via the drive mains input.
It is important that the level of interference fed back to the mains supply via path I
PE
is minimised because all
other equipment in the installation is also connected to this same mains supply and could therefore be affected
by this interference. Adding an EMI filter provides a low impedance path for interference currents from the earth
plane back to the PDS via path I
LF
and will reduce mains supply interference currents I
PE
.
To ensure the installation conforms to the EMC Directives, both of the following actions must be completed by the
installer;
1. Select appropriate EMC components, and
2. Implement appropriate wiring setups to limit high-frequency harmonic effects.
Warning!
EMC related performance, however, can still be influenced by factors not covered by the configuration
details supplied in this section of the manual. It is difficult to consider all necessary wiring and conditions of the
equipment particular to all possible customer needs. For this reason, the EMC conformance of the system as a
whole must be confirmed by the customer in accordance to the appropriate standards for their application and
market.
Line Reactor
Line Filter
AMD5x Drive
Motor Cable
I
leak
PE terminal and metal gear tray ground
PE
I
PCC
Distribution Transformer
Converter Cabinet
LF
I
DC
I
Heatsink
AMD5x PIU
Figure 5-5: Common Mode Noise Current Paths in a Drive System
