Certification
Page
C-8
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D
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A
B
C
D
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2
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E
Long cable lengths may have the following undesirable effects:
♦
Tripping on `overcurrent’ as the cable capacitance is charged and discharged at the switching frequency.
♦
Producing increased conducted emissions that degrade the performance of the EMC filter due to
saturation.
♦
Causing RCDs (Residual Current Devices) to trip due to increased high frequency earth current.
♦
Producing increased heating inside the EMC ac supply filter from the increased conducted emissions.
These effects can be overcome by adding chokes or output filters at the output of the VSD.
Emissions
All VSDs potentially produce electrical emissions which are radiated into the environment and conducted
back into the ac supply. The following information is provided to maximise the Electro Magnetic
Compatibility (EMC) of VSDs and systems in their intended operating environment, by minimising their
emissions.
The standards are concerned with two types of emission
♦
Radiated
Those in the band 30MHZ – 1000MHz which radiate into the environment
♦
Conducted
Those in the band 150kHz – 30MHz which are injected into the supply.
