Chapter 2 Wiring of V 810
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2.7.2 EMC properties of the converter
Like other electrical or electronic devices, the inverter is not only a source of
electromagnetic interference, but also an electromagnetic receiver. The principle of
operation of the converter determines that it can produce some electromagnetic
interference.
At the same time, the inverter should be designed with some interference immunity to
ensure trouble-free operation in a certain electromagnetic environment. The EMC
functions of the inverter are as follows:
1. / The input current is without sine wave. The input current contains a large number of
higher harmonic frequencies, which can cause electromagnetic interference, reduce the
power factor and increase line losses.
2./ The output voltage is a high frequency PMW wave that can cause the motor
temperature to rise and shorten its life. It will also increase the leakage current, which can
lead to equipment failure and create strong electromagnetic interference affecting the
reliability of other electrical equipment.
3./ As an electromagnetic receiver, too much interference will damage the inverter and
affect its normal operation. EMS and EMI inverters coexist in the system. Reducing the
EMI of the drive can increase its EMS capability.
2.7.3 EMC installation instructions
To ensure the smooth operation of all electrical equipment in the same system, this
section, based on the EMC characteristics of the inverter, outlines the EMC installation
procedure in several aspects of the application (noise control, wiring, grounding, leakage
current and power filter). The good effectiveness of EMC will depend on the effect of all
five aspects.
1./ Noise reduction
All cables connected to the control terminals must be shielded. The conductor shield must
be grounded near the inverter input conductor. The grounding method is by means of a
360 ° stepped ring cable clamp. It is strictly forbidden to connect the twisted shielding
layer to the ground of the inverter, which significantly reduces or suppresses the shielding
effect.
Connect the inverter and motor using a shielded wire or a separate cable route. One side
of the shield or metal cover of the cable route should be connected to ground and the
other side should be connected to the motor cover. Electromagnetic noise can be
significantly reduced by installing an EMC filter.
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