Megmeet MV820 - Leakage Current and Measures

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4.3.5 Leakage current and measures
The leakage current passes the line capacitor and motor capacitor at the input and output ends of the drive. Its
magnitude depends on the distributed capacitance and carrier frequency. The leakage current includes the grounding
leakage current and line-to-line leakage current.
Fig. 4-34 Leakage current path
(1) Grounding leakage current
The leakage current will not only pass the drive system, but also pass other equipment through the grounding cable,
causing misoperation of the leakage circuit breaker, relay and other equipment. The higher the carrier frequency, or the
longer the motor cable is, the larger the leakage current will be.
Suppression measures:
 Lower the carrier frequency, but the motor noise will increase;
 Shorten the motor cable;
 Adopt the leakage current breaker designed for the leakage current of high harmonics/surge in the drive system and
other systems;
 Try to disconnect the EMC capacitor connection screw to avoid leakage protection, as shown in Fig. 4-35.
Fig. 4-35 Connection screws for EMC capacitor and varistor