Chapter 6 Troubleshooting
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Ch
ap
ter 6
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.
