Precautions On Installing Emc Input Filter At The Input End Of Power Supply - Powtran PI9100 Series Manual

Chapter 6 EMC (Electromagnetic Compatibility)
current to the earth, and the other is leakage current between the cables.
1) Factors of affecting leakage current to the earth and its solutions:
There are the distributed capacitance between the lead cables and the earth. The
larger the distributed capacitance, the larger the leakage current; the distributed
capacitance can be reduced by effectively reducing the distance
between the inverter and the motor. The higher the carrier frequency, the larger the
leakage current. The leakage current can be redUced by reducing the carrier frequency.
However, the carrier frequency reduced may result in
the increase of motor noise.Please note that additional installation of reactor is also
an effective method to solve leakage current problem.
The leakage current may increase with the increase of circuit current. Therefore,
when the motor power is higher, the corresponding leakage current will be higher too.
2) Factors of producing leakage current between the cables and its solutions:
There is the distributed capacitance between the output cables of the inverter. If the
current passing lines has higher harmonic, it may cause resonance and thus result in
leakage current. If the thermal relay is used, it may generate error action.
The solution is to reduce the carrier frequency or install output reactor. It is
recommended that the thermal relay shall not be installed in the front of the motor when
using the inverter, and that electronic over current protection function of the inverter
shall be used instead.

6-3-6.Precautions on installing EMC input filter at the input end of power supply

1) Note: when using the inverter, please follow its rated values strictly. Since the
filter belongs to Classification I electric appliances, the metal enclosure of the filter and
the metal ground of the installing cabinet shall be well earthed in a large area, and have
good conduction continuity, otherwise there may be danger of electric shock and the
EMC effect may be greatly affected. Through the EMC test, it is found that the filter
ground end and the PE end of the inverter must be connected to the same public earth
end, otherwise the EMC effect may be greatly affected.
2) The filter shall be installed at a place close to the input end of the power supply
as much as possible.
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