Hub van Doorneweg 8 • 2171 KZ Sassenheim – NL •
T
+31(0)252 228850 •
F
+31(0)252 228235 •
E
I
euronormdrives.com
56
57
NEURN030000_220_A
NEURN030000_220_A
8.3.5 Remedies for leakage current
There are two forms of leakage current when using the inverter. One is leakage 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.
8.3.6 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.
