Grounding; Extra Protection (Rcd); Rfi Switch; Torque - Danfoss VLT AQUA Drive FC 202 Operating Instructions Manual

How to Install

4.1.2 Grounding

To obtain electromagnetic compatibility (EMC), consider
the following basic issues when installing a frequency
converter.
•
Safety grounding: The frequency converter has a
high leakage current (> 3.5 mA) and must be
grounded appropriately for safety reasons. Apply
local safety regulations.
•
High-frequency grounding: Keep the ground wire
connections as short as possible.
Connect the different ground systems at the lowest
possible conductor impedance. This is obtained by keeping
the conductor as short as possible and by using the
greatest possible surface area.
The metal cabinets of the different devices are mounted
on the cabinet rear plate using the lowest possible High-
frequency impedance. This avoids having different High-
frequency voltages for the individual devices and avoids
the risk of radio interference currents running in any
connection cables used between the devices. The radio
interference has been reduced.
To obtain a low High-frequency impedance, use the
fastening bolts of the devices as High-frequency
connection to the rear plate. Remove any insulating paint
or similar from the fastening points.

4.1.3 Extra Protection (RCD)

If local safety regulations are complied with, ELCB relays,
multiple protective earthing or grounding can be used as
extra protection.
A ground fault may cause a DC component to develop in
the fault current.
If ELCB relays are used, observe local regulations. Relays
must be suitable for the protection of 3-phase equipment
with a bridge rectifier and for a brief discharge on power-
up.
See also Special Conditions in the product relevant design
guide.

4.1.4 RFI Switch

Mains supply isolated from ground
1)
Turn off (OFF) the RFI switch via 14-50 RFI Filter on the
frequency converter and 14-50 RFI Filter on the filter if:
•
The frequency converter is supplied from an
isolated mains source (IT mains, floating delta and
grounded delta).
•
The frequency converter is supplied from TT/TN-S
mains with grounded leg.
MG20Y202
Operating Instructions
For further reference, see IEC 364-3.
Set 14-50 RFI Filter to [ON] if:
•
•
•
1)
Not available for 525-600/690 V frequency converters.
In OFF, the internal RFI capacities (filter capacitors)
between the chassis and the intermediate circuit are cut
off to avoid damage to the intermediate circuit and to
reduce the ground capacity currents (according to IEC
61800-3).
Also refer to the application note VLT on IT mains. It is
important to use isolation monitors which are compatible
with power electronics (IEC 61557-8).

4.1.5 Torque

When tightening all electrical connections, it is important
to tighten with the correct torque. Too low or too high
torque results in a poor electrical connection. Use a torque
wrench to ensure correct torque.
Nm/in-lbs
Illustration 4.12 Tightening Torques.
Enclosure size Terminal
F8-F14
Table 4.2 Tightening Torques
Danfoss A/S © Rev. 06/2014 All rights reserved.
Optimum EMC performance is needed.
Parallel motors are connected.
The motor cable length is above 25 m.
Torque
Mains
19-40 Nm
Motor
(168-354 in-
lbs)
Brake 8.5-20.5 Nm
Regen (75-181 in-lbs)
4 4
Bolt size
M10
M8
35