Screened/Armoured Cables; Extra Protection; High Voltage Test - Danfoss VLT 2800 Design Manual

Installation
lation and the sensitivity of the signal cables. For this
reason, exact values cannot be given.
When being placed in cable trays, sensitive cables may not
be placed in the same cable tray as the motor cable. If
3 3 signal cables run across power cables, this is done at an
angle of 90 °. Only use screened/armoured noise-filled
inlet and outlet cables to a cabinet.
See also chapter 3.3.7 EMC-correct Electrical Installation.

3.3.4 Screened/armoured Cables

The screen must have low HF impedance, which is
achieved by a braided screen of copper, aluminium or iron.
Screen reinforcement intended for mechanical protection,
for example, is not suitable for EMC-correct installation.
See also chapter 3.3.8 Use of EMC Compliant Cables.

3.3.5 Extra Protection

RCD relays, multiple protective earthing or grounding can
be used as extra protection, provided that local safety
regulations are complied with. If a ground fault occurs, a
DC content may develop in the faulty current. Never use
an RCD (ELCB relay), type A, as it is not suitable for DC
faulty currents. If RCD relays are used, comply with local
regulations.
If RCD relays are used, they must be:
•
Suitable for protecting equipment with a DC
content in the faulty current (3-phase bridge
rectifier).
•
Suitable for a pulse-shaped, brief discharge on
power-up.
•
Suitable for a high leakage current.
N must be connected before L1 for single-phase 200 V
reduced leakage current units (type code R4).

3.3.6 High Voltage Test

A high-voltage test can be performed by short-circuiting
terminals U, V, W, L1, L2 and L3, and applying max. 2160 V
DC in 1 s between this short-circuit and terminal 95.
WARNING
Do not perform a high-voltage test between the control
terminals and the chassis, because the voltage potential
of the control card cannot exceed approximately 100 V
with respect to chassis due to a voltage limiting circuitry.
Performing such a test may lead to equipment damage
and personal injuries.
The terminals are protected against direct hazardous
access through barriers.
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Design Guide
Danfoss A/S © Rev. May/2014 All rights reserved. MG27E402