Leakage Current - Danfoss VLT AQUA Drive FC 202 Design Manual

Electrical Installation Con...

10.9 Leakage Current

Follow national and local codes regarding protective
grounding of equipment where leakage current exceeds
3.5 mA.
Drive technology implies high-frequency switching at high
power. This high-frequency switching generates a leakage
current in the ground connection.
The ground leakage current is made up of several contri-
butions and depends on various system configurations,
including:
•
RFI filtering.
•
Motor cable length.
•
Motor cable screening.
•
Drive power.
Leakage current
Illustration 10.11 Motor Cable Length and pPower Size
Influence the Leakage Current. Power Size a > Power Size b.
The leakage current also depends on the line distortion.
MG22B102
Design Guide
Leakage current
Illustration 10.12 Line Distortion Influences Leakage Current
a
If the leakage current exceeds 3.5 mA, compliance with
EN/IEC61800-5-1 (power drive system product standard)
requires special care.
Reinforce grounding with the following protective earth
connection requirements:
b
•
Motor cable length
•
See EN/IEC61800-5-1 and EN 50178 for further information.
Danfoss A/S © 05/2017 All rights reserved.
Ground wire (terminal 95) of at least 10 mm
AWG) cross-section.
2 separate ground wires both complying with the
dimensioning rules.
THDv=0%
THDv=5%
10
2
(8
85
10