REGULATORY COMPLIANCE UL AND CE
94 IPA Hardware Installation Guide
Figure 36. - 360° Bonding Techniques
All braid termination connections must remain secure. For small diameter cables, it may be necessary to fold back
the braid to increase the effective diameter of the cable so that R-Clamps are secure.
Within the cabinet itself, all the motor cables should lie in the same trunking as far as possible. Keep these and any
high power cables separate from any low-level control signal cables. This applies particularly where the control
cables are unscreened and run close to the drive. If high power and low-level cables must cross, attempt to avoid
running them parallel and cross them at 90 degrees.
There must be no break in the 360° coverage that the screen provides around the cable conductors. Pigtail braid
connections will adversely affect EMC performance and are to be avoided.
A steel equipment cabinet will screen radiated emissions provided all panels are bonded to a central earth point.
Separate earth circuits are commonly used within equipment cabinets to minimize the interaction between
independent circuits. A circuit switching large currents and sharing a common earth return with another low-level
signal circuit could conduct electrical noise into the low level circuit, thereby possibly interfering with its
operation. For this reason, so called ‘dirty earth’ and ‘clean earth’ circuits may be formed within the same cabinet,
but all such circuits will eventually need to be returned to the cabinet’s main star earth point.
Mount the individual drives and EMC filter on a metal earth plane. The earth plane will have its own individual star
point earth that should be hard wired (using an insulated copper conductor) back to the cabinet’s ‘clean earth’
connection point.
Panel mounting can provide a similar measure of EMC performance if strict attention is paid to cable screen
termination and cable layout.
Again, the machine builders primary focus should be on ensuring operators are kept safe from all hazards.
Install a Mains filter. IPA drives require a mains supply filter to meet EMC emission requirements. It is
recommended that the drive is mounted on a conductive panel which is shared with the EMC filters. If the panel
has a paint finish, it will be necessary to remove the paint in certain areas to ensure filters and drive make a good
large-area surface metal to metal contact between filter case and panel.
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