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C The surrounding equipment is separately earthed , which can avoid the interference caused by the、
leakage current of the inverter’s earth wire when common earth mode is adopted .
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 .
There are distributed capacitance between the lead cables and the earth . The larger the distributed
The leakage current may increase along with the addition of circuit current . Therefore , when motor
There is distributed capacitance between the output cables of the inverter . If the current passing the
The solution is to reduce the carrier frequency or install output reactor . It is recommended that
thermal relay should not be installed before the motor when the inverter is working , and electronic over current
protection function of the inverter could be used instead .
lines has higher harmonic , it may cause resonance and thus result in leakage current . if thermal relay is
used , it may generate error action .
power is high , the corresponding leakage current will be high too .
capacitance is , the larger the leakage current will be . The distributed capacitance can be reduced by
effectively reducing the distance between the inverter and the motor . The higher the carrier frequency is,
the larger the leakage current will be . The leakage current can be reduced by reducing the carrier frequency .
However , reducing the carrier frequency may result in addition of motor noise . Note that additional
installation of reactor is also an effective method to remove the leakage current .
Chapter 3 Mechanical and Electrical Installation
3 Leakage current and handling、
1) Factors influencing the leakage current to the earth and the solutions :
2) Factors of producing leakage current between the cables and solutions :
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