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6<br />
<strong>Grundfos</strong> E-<strong>pumps</strong><br />
EMC<br />
Back plate<br />
Control panels are often made of metal and/or have<br />
a metal back plate. This back plate can therefore be<br />
used as reference for all screening, i.e. all screens are<br />
connected to this back plate via cable brackets.<br />
When installing the cable brackets, make sure that<br />
they have a good electrical connection to the metal<br />
back plate. Therefore, any painting and surface<br />
treatment must be removed.<br />
b) Extension of control cable<br />
If an extension of the screened control cable is<br />
required, it must be made properly.<br />
As shown in fig. 62, both cable ends must be closed by<br />
a cable bracket to the common back plate and the<br />
unscreened cable ends must be as short as possible.<br />
Control signal from E-<strong>pumps</strong> to control<br />
panel<br />
a) Unbroken control cable<br />
An unbroken connection from the E-pump to the<br />
connection in the control panel is always preferable.<br />
Immediately after entry of the cable into the panel,<br />
remove a piece of insulation, and connect the screen<br />
to the back plate via a cable bracket. See page 61.<br />
Back plate<br />
Electronic unit<br />
Screen to back<br />
plate via bracket<br />
Fig. 61 Schematic drawing of connection of cable to back<br />
plate<br />
Connect the cable to the back plate of the control<br />
panel close to the final connection. The unscreened<br />
cable ends must be as short as possible.<br />
TM03 0249 5004<br />
Fig. 62 Schematic drawing of extension of control cable<br />
Keep as long a distance as possible to contactors and<br />
power current installation.<br />
Other conditions of importance<br />
Unscreened cable sections must be twisted-pair<br />
cables and as short as possible.<br />
Non-conductive panels<br />
Control panels not made of metal and with metal back<br />
plate are generally a bad solution with regard to EMC.<br />
In such cases, it is of great importance to be careful<br />
with the placing of the different types of unit and to<br />
keep distance between the noisy and sensitive units.<br />
Cabling<br />
Do not place the control signal cables in the same<br />
bunch as the power cables. A distance of 4 to 8 in.<br />
(10 to 20 cm) between the two groups should be<br />
observed.<br />
TM03 0250 5004<br />
54
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