VLT
®
8000 AQUA
All about VLT 8000
AQUA
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Ground leakage current
Ground leakage current is primarily caused by the
capacitance between motor phases and the motor
cable shield. See drawing on the following page. The
size of the leakage current to the ground depends
on the following factors, in order of priority:
1. Length of motor cable
2. Motor cable with or without shield
3. Switching frequency
4. RFI filter used or not
5. Motor grounded on site or not
The leakage current is of importance to safety
during handling/operation of the AFD if (by mistake)
the AFD has not been grounded.
NOTE
RCD
Since the leakage current is > 3.5 mA, reinforced
earthing/grounding must be established, which
is required if EN 50178 is to be complied with. Never
use ELCB relays (type A) that are not suitable for DC
fault currents from three-phase rectifier loads.
If ELCB relays are used, they must be:
-
Suitable for protecting equipment with a direct
current content (DC) in the fault current
(3-phase bridge rectifier)
-
Suitable for power-up with short pulse-shaped
charging current to ground
-
Suitable for a high leakage current (300 mA)
Leakage currents to ground
MG.80.A7.22 - VLT is a registered Danfoss trademark
179
Rosewood STP ST42 General (Operation and Maintenance Manual - Part 4:
Section 6.3 Manufacturers Manuals 6.3.33 Danfoss VLT Aquadrive 8000) Vendor Manual
QP Id: VM207
Active: 03/09/2013
Page 185 of 208