Galvanic Isolation (Pelv); Earth Leakage Current - Danfoss VLT AutomationDrive FC 300 Design Manual

FC 300 Design Guide

Galvanic Isolation (PELV)

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PELV offers protection by way of extra low voltage. Protection against electric shock is
ensured when the electrical supply is of the PELV type and the installation is made as
described in local/national regulations on PELV supplies.
All control terminals and relay terminals 01-03/04-06 comply with PELV (Protective Extra Low Voltage)
(Does not apply to 525-600 V units and at grounded Delta leg above 300 V).
Galvanic (ensured) isolation is obtained by fulfilling requirements for higher isolation and by providing the
relevant creapage/clearance distances. These requirements are described in the EN 61800-5-1 standard.
The components that make up the electrical isolation, as described below, also comply with the
requirements for higher isolation and the relevant test as described in EN 61800-5-1.
The PELV galvanic isolation can be shown in six locations (see illustration):
Power supply (SMPS) incl. signal isolation of
1.
U , indicating the intermediate current voltage.
DC
Gate drive that runs the IGBTs (trigger
2.
transformers/opto-couplers).
Current transducers.
3.
Opto-coupler, brake module.
4.
Internal inrush, RFI, and temperature
5.
measurement circuits.
Custom relays.
6.
The functional galvanic isolation (a and b on drawing) is for the 24 V back-up option
and for the RS 485 standard bus interface.

Earth Leakage Current

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Warning:
Touching the electrical parts may be fatal - even after the equipment has
been disconnected from mains.
Also make sure that other voltage inputs have been disconnected, such as load-sharing (linkage
of DC intermediate circuit), as well as the motor connection for kinetic back-up.
Using VLT AutomationDrive FC 300 (at and below 7.5 kW): wait at least 2 minutes.
Leakage Current
The earth leakage current from the FC 300 exceeds 3.5 mA. To ensure that the earth cable has
a good mechanical connection to the earth connection (terminal 95), the cable cross section
must be at least 10 mm
Residual Current Device
This product can cause a d.c. current in the protective conductor. Where a residual current device
(RCD) is used for extra protection, only an RCD of Type B (time delayed) shall be used on the
supply side of this product. See also RCD Application Note MN.90.GX.02.
Protective earthing of the frequency converter and the use of RCD's must always
follow national and local regulations.
Introduction to FC 300
Galvanic isolation
2 or 2 rated earth wires terminated separately.
MG.33.B4.02 - VLT is a registered Danfoss trademark
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