Certification
Page C-14 890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D
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4. Signal/Control Screen Earth Busbar (insulated from the mounting panel)
Used for signal/control screened cables which do not go directly to the VSD. Place this busbar as close
as possible to the point of cable entry. ‘U’ clamp the screened cables to the busbar to ensure an optimum
HF connection.
Sensitive Equipment
The proximity of the source and victim circuit has a large effect on radiated coupling. The electromagnetic
fields produced by VSDs falls off rapidly with distance from the cabling/cubicle. Remember that the
radiated fields from EMC compliant drive systems are measured at least 10m from the equipment, over the
band 30-1000MHz. Any equipment placed closer than this will see larger magnitude fields, especially when
very close to the drive.
Do not place magnetic/electric field sensitive equipment within 0.25 metres of the following parts of the
VSD system:
♦ Variable Speed Drive (VSD)
♦ EMC output filters
♦ Input or output chokes/transformers
♦ The cable between VSD and motor (even when screened/armoured)
♦ Connections to external braking chopper and resistor (even when screened/armoured)
♦ AC/DC brushed motors (due to commutation)
♦ DC link connections (even when screened/armoured)
♦ Relays and contactors (even when suppressed)
From experience, the following equipment is particularly sensitive and requires careful installation:
♦ Any transducers which produce low level analogue outputs (<1V) , e.g. load cells, strain gauges,
thermocouples, piezoelectric transducers, anemometers, LVDTs
♦ Wide band width control inputs (>100Hz)
♦ AM radios (long and medium wave only)
♦ Video cameras and closed circuit TV
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