Danfoss VLT HVAC Drive FC 100 Instruction Manual page 59

4 How to Install
1) External Temperature Monitoring
2) AUX Relay
01 02 03
04 05 06
3) NAMUR
4) AUX Fan
100 101 102 103
L1 L2 L1
5) Brake
-R +R
81 82
4
4.6.2 Grounding
The following basic issues need to be considered when installing an adjustable frequency drive, so as to obtain electromagnetic com-
patibility (EMC).
• Safety grounding: Please note that the adjustable frequency drive has a high leakage current and must be grounded appropriately for safety
reasons. Always follow 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. The lowest possible conductor impedance 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 HF impedance. This prevents having different
HF voltages for the individual devices and prevents the risk of radio interference currents running in connection cables that may be used between the
devices, as radio interference is reduced.
In order to obtain a low HF impedance, use the fastening bolts of the devices as HF connections to the rear plate. It is necessary to remove insulating
paint and the like from the fastening points.
4.6.3 Extra Protection (RCD)
ELCB relays, multiple protective grounding or grounding can be used as extra protection, provided that local safety regulations are complied with.
In the case of a ground fault, a DC component may develop in the fault current.
If ELCB relays are used, local regulations must be observed. Relays must be suitable for protection of 3-phase equipment with a bridge rectifier and for
a brief discharge on power-up.
See also the section Special Conditions
4-42
L2
in the Design Guide.
MG.16.A1.22 - VLT
VLT HVAC Low Harmonic Drive Instruction
6) Motor
U V W
96 97 98
T1 T2 T3
7) NAMUR Fuse. See fuse tables for part numbers
8) Fan Fuses. See fuse tables for part numbers
9) SMPS Fuses. See fuse tables for part numbers
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is a registered Danfoss trademark
Manual