12-6 Certification for the Inverter
605C Frequency Inverter
3 Metal Work Earth Busbar
The back panel is used as this earth busbar, and should provide earthing points for all parts of
the cubicle including panels and doors. This busbar is also used for power screened cables
which terminate near to (10cm) or directly into a VSD - such as motor cables, braking choppers
and their resistors, or between VSDs - refer to the appropriate product manual to identify these.
Use U-clips to clamp the screened cables to the back panel to ensure optimum HF connection.
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 busbars 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 Inverter.
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 analog 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
• Office personal computers
• Capacitive devices such as proximity sensors and level transducers
• Mains borne communication systems
• Equipment not suitable for operation in the intended EMC environment, i.e. with
insufficient immunity to new EMC standards
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