Shanghai STEP Electric Corporation
Appendix A EMC Installation Guide
Fig 4.1 Use Requirements of Relay, Contactor and Electromagnetic Brake
A5 Leakage Current and Countermeasures
Figure A5.1 shows the wiring capacitance, motor capacitance, ground leakage current and
line-to-line leakage current by the input/output side of elevator integrated drive controller. The
intensity of leakage current depends upon the carrier frequency and capacitance.
Fig A5.1 Paths of Leakage Current
A5.1 Ground Leakage Current
Ground leakage current not only flows by elevator integrated drive controller but also flows by
other equipment via the ground wire. As a result, it may cause malfunction of leakage protection
circuit breaker, relay or other equipment. The leakage current increases with the increment of
carrier frequency of elevator integrated drive controller and the extension of motor cable.
Suppression measures: reduce carrier frequency; shorten motor cable as practicably as possible;
use leakage protection circuit breaker specially designed for leakage current due to higher
harmonic/surge.
A5.2 Line-to-Line Leakage Current
As for leakage current flowing by the distributed capacitance between I/O side cables of elevator
integrated drive controller, its higher/sub harmonics may cause malfunction of external
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