Specifications

2.8.6 Immunity Requirements
The immunity requirements for frequency converters
depend on the environment where they are installed. The
requirements for the industrial environment are higher
than the requirements for the home and office
environment. All Danfoss frequency converters comply
with the requirements for the industrial environment and
consequently comply also with the lower requirements for
home and office environment with a large safety margin.
2.9 Galvanic Isolation (PELV)
2.9.1 PELV - Protective Extra Low Voltage
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 440 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, 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
Illustration 2.26.
To maintain PELV all connections made to the control
terminals must be PELV, e.g. thermistor must be
reinforced/double insulated.
0.25-22 kW
SMPS
130BB896.10
1
2
3
a
M
Illustration 2.25 Galvanic Isolation
1 Power supply (SMPS)
2 Optocouplers, communication between AOC and BOC
3 Custom relays
a Control card terminals
Table 2.23 Legend to Illustration 2.25
30-90 kW
130BB901.10
1
3
24
5
a
M
Illustration 2.26 Galvanic Isolation
1 Power supply (SMPS) incl. signal isolation of UDC, indicating
the intermediate current voltage
2 Gate drive that runs the IGBTs (trigger transformers/opto-
couplers)
3 Current transducers
4 Internal soft-charge, RFI and temperature measurement
circuits
5 Custom relays
a Control card terminals
Table 2.24 Legend to Illustration 2.26
The functional galvanic isolation (see Illustration 2.25) is for
the RS-485 standard bus interface.
CAUTION
Installation at high altitude:
At altitudes above 2 km, contact
Danfoss regarding PELV.
Product Overview
VLT
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HVAC Basic Drive FC 101 Design Guide
MG18C502 - Rev. 2013-09-06 37
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