Figure 7.57 Electrical Connection Diagram (6-pulse example
shown)
7.8.2 Use of EMC-Compatible Cables
Danfoss recommends braided shielded/armored cables to
optimize EMC immunity of the control cables and the EMC
emission from the motor cables.
The cable’s ability to reduce the incoming and outgoing
radiation of electric noise depends on the transfer
impedance (ZT). The cable’s shield is normally designed to
reduce the transfer of electric noise; however, a shield with
a lower transfer impedance (Z
T
) value is the most effective.
Cable manufacturers rarely state transfer impedance (Z
T
),
but it is often possible to estimate transfer impedance (Z
T
)
by assessing the physical design of the cable. See
Figure 7.58 Transfer Impedance Z
T
7.8.3 Grounding of Shielded Control Cables
Correct Shielding
The preferred method is to secure control and serial
communication cables with shielding clamps at both ends
to ensure best possible high frequency cable contact.
If the ground potential between the adjustable frequency
drive and the PLC is different, electric noise may occur.
Solve this problem by fitting an equalizing cable next to
the control cable. Minimum cable cross section is 0.025 in
2
[16 mm
2
].
Electrical Installation
Design Guide
236
Danfoss A/S © Rev. 2014-02-10 All rights reserved.
MG34S222
7
7
Summary of Contents for VLT AutomationDrive FC 300
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