Galvanic Isolation (Pelv) - Danfoss VLT DriveMotor FCP 106 Design Manual

Product Overview
RCD with low f
Leakage current
RCD with high f
50 Hz 150 Hz
Mains 3rd harmonics
Illustration 2.23 Main Contributions to Leakage Current
The amount of leakage current detected by the RCD
depends on the cut-off frequency of the RCD.
Leakage current [mA]
Illustration 2.24 Influence of the RCD Cut-off Frequency on
Leakage Current
WARNING
SHOCK HAZARD
The frequency converter can cause a DC current in the
PE conductor and thus result in death or serious injury.
•
When a residual current-operated protective
device (RCD) is used for protection against
electrical shock, only an RCD of Type B is
permitted on the supply side.
Failure to follow the recommendation means that the
RCD cannot provide the intended protection.
MG03M202
Design Guide
cut-
cut-
f Frequency
sw
Cable
100 Hz
2 kHz
100 kHz
Danfoss A/S © 06/2016 All rights reserved.

2.8 Galvanic Isolation (PELV)

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 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/IEC 61800-5-1 standard.
The components that make up the electrical isolation also
comply with the requirements for higher isolation and the
relevant test as described in EN/IEC 61800-5-1.
The PELV galvanic isolation is shown in Illustration 2.25.
To maintain PELV, all connections made to the control
terminals must fulfil the requirements for PELV.
2
+24 V
18
Control
Functional
isolation
RS485
Relay
output
3
1 High-voltage circuit
2 I/O control card
3 Custom relays
Illustration 2.25 Galvanic Isolation
NOTICE
HIGH ALTITUDE
For installation at altitudes above 2000 m (6562 ft),
contact Danfoss hotline regarding clearance (PELV).
PELV isolation
1
Mains
High
voltage
Motor
DC bus
Thermistor
input
27
2 2