FR200 Series Vector control inverter
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3.9 EMI Solutions
Due to its working principle, the drive will inevitably produce certain noise that may influence and
disturb other equipment. Moreover, since the internal weak electric signal of drive is also susceptible
to the interference of drive itself and other equipment, EMI problems shall be inevitable. In order to
reduce or avoid the interference of drive to external environment and protect drive against interference
from external environment, this section makes a brief description of noise abatement, ground handling,
leakage current suppression and the application of power line filters.
3.9.1 Noise Abatement
When peripheral equipment and drive share the power supply of one system, noise from drive
may be transmitted to other equipment in this system via power lines and result in misoperation
and&or faults. In such a case, the following measures could be taken:
1) Mount input noise filter at input terminal of the drive;
2) Mount power supply filter at power input terminal of affected equipment;
3) Use isolation transformer to isolate the noise transmission path between other equipment and the
drive.
leakage current of inverter will cause equipment misoperation and/or faults.
Disconnect the grounding connection of equipment may avoid this misoperation and/or faults
could be put into metallic conduits between which the distance shall be no less than 20cm, and shall
be kept as far away from drive and its peripheral devices, cables as possible. Never make signal lines
in parallel with power lines or bundle them up.
this cross inevitable.
-thick pipelines or buried
cement groove, also, power lines can be put into metallic conduit and grounded well with shielded
cables.
-core motor cables of which one is grounded at close side of the drive and the other side is
connected to motor enclosure.
filter. For example, ferrite common mode choke can restrain radiation noise of power lines.
3.9.2 Grounding
Recommended ground electrode is shown in the figure below:
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Fig 3-28 Inverter grounding diagram
Use to the fullest extent the maximum standard size of grounding cables to reduce the impedance of
grounding system;
Grounding wires should be as short as possible;
Grounding point shall be as close to the drive as possible;
-core motor cables shall be grounded at the drive side and connected to grounding
terminal of motor at the other side. Better effect will be achieved if motor and drive are provided with
dedicated ground electrodes;
When grounding terminals of various parts of system are linked together, leakages current turns into
a noise source that may influence other equipment in the system, thus, grounding terminals of the
drive and other vulnerable equipment should be separated.
e kept away from inlet & output of noise-sensitive equipment.
3.9.3 Leakage Current Suppression
Leakage current passes through the line-to-line and ground distributed capacitors at input & output
sides of drive, and its size is associated with the capacitance of distributed capacitor and the carrier
frequency. Leakage current is classified into ground leakage current and line-to-line leakage current.
Ground leakage current not only circulates inside drive system, but may also influence other
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