Chapter 7—EMC Installation
42 DG1 Series VFD MN040002EN—March 2014 www.eaton.com
International EMC Protection Cable
Requirements
The screened cables between the variable frequency drive
and the motor should be as short as possible.
●
Connect the screening, on both sides and across a large
area (360° overlap), to the protective earth (PE). The power
screening protective earth (PES) connection should be in
the immediate proximity of the variable frequency drive
and directly on the motor terminal box.
●
Prevent the screening from becoming unbraided, e.g., by
pushing the opened plastic sheath over the end of the
screening or with a rubber grommet on the end of the
screening. As an alternative, in addition to a broad area
cable clip, you can also twist the shielding braid at the end
and connect to protective ground with a cable clip. To
prevent EMC disturbance, this twisted shielding
connection should be made as short as possible
●
Screened three- or four-wire cable is recommended for the
motor cables. The green/yellow line of a four-wire cable
connects the protective ground connections from the
motor and the variable frequency drive and therefore
minimizes the equalizing current loads on the shielding
braid.
●
If there are additional subassemblies in a motor feeder
(such as motor contactors, overload relays, motor reactor,
sinusoidal filters or terminals), the shielding of the motor
cable can be interrupted close to these subassemblies and
connected to the mounting plate (PES) with a large area
connection.
Free or non-screened connection cables should not be any
longer than about 300 mm.
Table 25. 1st Environment 2nd Environment EMC Levels
According to EN 61800-3 (2004)
Note
1
360° earthing of the shield with cable glands in motor end needed for
EMC Level C2.
Table 26. Control Wiring Requirements
Table 27. Cable Categories
Figure 28. Cable Description
Cable Type Category C2 Category C3 Level T
Line voltage/mains 1 1 1
Motor cable 3
1
22
Control cable 4 4 4
Item Directive
Product IEC 61800-2
Safety UL 508C, IEC / EN 61800-5-1
EMC (at default
settings)
Immunity: EN / IEC 61800-3, 2nd environment
Radiated emissions: EN / IEC 61800-3 (Transient Testing
included), 1st environment
Conducted emissions: EN / IEC 61800-3
Category C1: is possible with external filter connected to
drive. Please consult factory
Category C2: with internal filter maximum of 10m motor
cable length
Category C3: with internal filter maximum of 50m motor
cable length
Cable
Category
Description
(All cables are rated for the specific operating voltage)
1 Intended for fixed installation
2 Symmetrical power cable equipped with a concentric protection
wire.
3 Symmetrical power cable with compact low-impedance shield.
Recommended cable transfer impedance of 1–30 MHz max.
See figure below.
4 Screened cable equipped with compact low-impedance shield
PE Conductor
and Shield
Shield
PE Conductor
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