130BB955.11
a
b
Cable length [m]
Leakage current [mA]
Illustration 2.19 Leakage Current Influenced by the Cable Length
and Power Size
The leakage current also depends on the line distortion.
130BB956.11
Leakage current [mA]
THVD=0%
THVD=5%
Illustration 2.20 Leakage Current Influenced by Line Distortion
NOTE
When a filter is used, remove the RFI screw (enclosure size
J1 to J5) or turn off
14-50 RFI Filter
(enclosure size J6 to J7)
when charging the filter, to avoid that a high leakage
current makes the RCD switch.
EN/IEC61800-5-1 (Power Drive System Product Standard)
requires special care if the leakage current exceeds 3.5mA.
Earth grounding must be reinforced in one of the
following ways:
•
Earth ground wire (terminal 95) of at least 10
mm
2
•
Two separate earth ground wires both complying
with the dimensioning rules
See EN/IEC61800-5-1 and EN50178 for further information.
Using RCDs
Where residual current devices (RCDs), also known as earth
leakage circuit breakers (ELCBs), are used, comply with the
following:
•
Use RCDs of type B only which are capable of
detecting AC and DC currents
•
Use RCDs with an inrush delay to prevent faults
due to transient earth currents
•
Dimension RCDs according to the system configu-
ration and environmental considerations
130BB958.11
L
leakage
[mA]
f [Hz]
f
sw
Cable
f
s
150 Hz
3rd harmonics
50 Hz
Mains
RCD with low f
cut-off
RCD with high f
cut-off
Illustration 2.21 Main Contributions to Leakage Current
Product Overview
VLT
®
AutomationDrive FC 360 Design Guide
36
MG06B202 - VLT
®
is a registered Danfoss trademark
2
2
