SHENZHEN INVT ELECTRIC CO., LTD. CHV160 Operation Manual
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value depends on distributed capacitances and carrier frequency of the inverter. The
over-ground leakage current, which is the current passing through the common earthwire, can
flow into not only inverter system but also other equipment through earthwire, making residual
current circuit breaker, relay or other devices malfunction. The value of line-to-line leakage
current, which means the leakage current passing through distributed capacitors of input wire
and output wire, depends on the carrier frequency of inverter, the length of motor cables and
their section areas. The higher carrier frequency of inverter, the longer of the motor cable
and/or the bigger cable section area, the heavier leakage current will occur.
Countermeasure
Decreasing the carrier frequency can effectively reduce the leakage current, and in the
case of motor cable is relatively long (longer than 50m), it is necessary to install AC reactor or
sinusoidal wave filter at the output side, and even longer, it is necessary to install one reactor
at every certain distance.
4.7.3.5 Noise Filter
Noise filter has a great effect of electromagnetic decoupling, and so even if the optimal
operation is fulfilled, it is preferred for customer to install it.
For inverter, noise filter has following categories:
1
Noise filter installed at the input side of inverter
2
Noise insulation for other equipment by means of isolation transformer or mains filter
