Galvanic Isolation (Pelv) - Danfoss VLT HVAC Drive FC 102 Design Manual

Introduction

2.10 Galvanic Isolation (PELV)

2.10.1 PELV - Protective Extra Low Voltage
PELV (Protective Extra Low Voltage) offers protection
through extra low voltage. To ensure protection against
electric shock, use a PELV electrical supply and install 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).
Galvanic (ensured) isolation is obtained by fulfilling
requirements for higher isolation and providing the
relevant creepage/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 is shown in six locations. See
Figure 2.28:
To maintain PELV, all connections made to the control
terminals must be PELV.
MG16C122
Design Guide
6
Figure 2.28 Galvanic Isolation
1 Power supply (SMPS) including signal isolation of U
indicating the intermediate current voltage
2 Gate drive that runs the IGBTs (trigger transformers/opto-
couplers)
3 Current transducers
4 Opto-coupler, brake module
5 Internal soft-charge, RFI and temperature measurement
circuits.
6 Custom relays
a Functional Galvanic Isolation
b Functional Galvanic Isolation
Table 2.17 Legend to Figure 2.28
The functional galvanic isolation is for the 24 V backup
option and for the standard bus interface.
WARNING
Installation at high altitude:
380–480 V, enclosure A, B and C: At altitudes above
6,600 ft [2 km], contact Danfoss regarding PELV.
380–480 V, enclosure D, E and F: At altitudes above
10,000 ft [3 km], contact Danfoss regarding PELV.
Danfoss A/S © Rev. 2014-01-13 All rights reserved.
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