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The type 6 and 7 620 filters are not of the footprint mounting design. These filters may be mounted to the left,
right, above, below or spaced behind the product, but can be mounted in two orientations i) flat against the wall
or ii) projecting over from the wall, mounting arrangements are shown in figures 3-9 and 3-10. Wallmount
applications require the EMC filter to be mounted in a separate suitable enclosure, and the gland box to be fitted
to the 620.
The EMC filter should be mounted as close to the 620 drive module as possible. The connection between the 620
and filter must always be as short as possible taking care not to obstruct any ventilation spacing and be
segregated from all other cables. If this cable/busbar exceeds 0.3m in length then it must be replaced with a
screened/armoured cable, with the screen/armour earthed at both the filter and inverter ends with large-area
contact surfaces, preferably with metal cable glands. The connection between the 620 drive module and the
motor must be installed away from all other cables or wires. Ideally the filter will be mounted onto the same
metallic panel as the drive. The RF connection between the inverter, filter and panel should be enhanced as
follows:
-
Remove any paint/insulation between the mounting points of the EMC filter, 620 drive module and
panel.
-
Liberally apply petroleum jelly over the mounting points and securing threads to prevent corrosion.
Alternatively conducting paint could be used on mounting panels.
-
If the proceeding is not possible, then the RF earth bond between the filter and 620 drive module is
usefully improved by making an additional RF earth connection using wire braid of at least 10 mm
2
cross sectional area (due to skin effect).
-
For wall mount application, ensure that the cable between the EMC filter and the 620 drive module
cable is passed through conduit mounted between the filter and the Gland Box. This cable must be as
short as possible and segregated from all other cables. The conduit must be electrically connected to
the filter and drive module gland box.
NOTE:
Metal surfaces such as eloxized or yellow chromed e.g. with cable mounting or 35 mm DIN rails,
screws and bolts have a high RF impedance which can be very detrimental for EMC performance.
Care should be taken to ensure that the protective earth (PE) conductor exiting from the filter is connected to the
protective earth connection of the 620 drive module. Any additional RF earth such as a cable screen is not a
protective earth. The EMC filter must be permanently earthed to prevent the risk of electric shock under
abnormal operating instances (such as the loss of one phase of the AC supply). Permanent earthing can be
achieved by either:
-
Using a copper protective earth conductor of at least 10 mm
2
or
-
Installing a second conductor in parallel connection with the protective conductor to a separate protective
earth terminal.
Each conductor shall on its own meet the requirements for a protective earth conductor. On all recommended
underfloor EMC filters two protective earth connections are provided for permanent earthing.
The recommended EMC filters are designed to operate from normal three-phases supplies which are balanced
with respect to earth (earth referenced supplies). This minimises the earth leakage current due to the filter
capacitors between phase and earth. On some specific customer sites the supply may not be balanced with respect
to earth (non-earth referenced supplies). The earth leakage currents would increase and interfere with the
operation of any earth-fault monitoring equipment. In addition the EMC performance of the filter will be
degraded. Eurotherm Drives do not recommend the use of AC supply filters on non earth-referenced supplies.
As with all power electronic drives the conducted emissions increase with motor cable length. EMC
conformance to the stringent limits is only guaranteed up to a cable length of 50 m (types 4, 5, 6 and 7).
This length can be increased. Refer to section entitled Motor Cable-length Limitations in this chapter.
If one EMC filter is to be used in an enclosure, then this filter should be mounted as close to the incoming AC
supply to the enclosure as possible.
This manual was downloaded on www.sdsdrives.com
+44 (0)117 938 1800 - info@sdsdrives.com