3.1.8.1 Cabinet Options and Ratings
Danfoss frequency converters are available with 3 different
protection ratings:
•
IP00 or IP20 for cabinet installation.
•
IP54 or IP55 for local mounting.
•
IP66 for critical ambient conditions, such as
extremely high (air) humidity or high concen-
trations of dust or aggressive gases.
3.1.9 Radio Frequency Interference
The main objective in practice is to obtain systems that
operate constantly without radio frequency interference
between components. To achieve a high level of immunity,
use frequency converters with high-quality RFI filters.
Use Category C1 filters specified in the EN 61800-3 which
conform to the Class B limits of the general standard EN
55011.
Place warning notices on the frequency converter if RFI
filters do not correspond to Category C1 (Category C2 or
lower). The responsibility for proper labelling rests with the
operator.
In practice, there are 2 approaches to RFI filters:
•
Built in to the equipment
-
Built-in filters take up space in the
cabinet but eliminate extra costs for
fitting, wiring, and material. However,
the most important advantage is the
perfect EMC conformance and cabling
of integrated filters.
•
External options
-
Optional external RFI filters that are
installed on the input of the frequency
converter cause a voltage drop. In
practice, this means that the full mains
voltage is not present at the frequency
converter input and a higher-rated
frequency converter may be necessary.
The maximum length of the motor cable
for compliance with EMC limits ranges
from 1–50 m. Costs are incurred for
material, cabling, and assembly. EMC
conformance is not tested.
NOTICE
To ensure interference-free operation of the frequency
converter/motor system, always use a category C1 RFI
filter.
NOTICE
VLT
®
Refrigeration Drive FC 103 units are supplied as
standard with built-in RFI filters conforming to category
C1 (EN 61800-3) for use with 400 V mains systems and
power ratings up to 90 kW or category C2 for power
ratings of 110–630 kW. FC 103 units conform to C1 with
screened motor cables up to 50 m or C2 with screened
motor cables up to 150 m. Refer to
for details.
3.1.10 PELV and Galvanic Isolation
Compliance
Ensure the protection against electric shock, when the
electrical supply is of the protective extra-low voltage
(PELV) type, and the installation complies with local and
national PELV regulations.
To maintain PELV at the control terminals, all connections
must be PELV, such as thermistors being reinforced/double
insulated. All Danfoss frequency converter control and
relay terminals comply with PELV (excluding grounded
Delta leg above 400 V).
Galvanic (ensured) isolation is obtained by fulfilling
requirements for higher isolation and by providing the
relevant creepage/clearance distances. These requirements
are described in the EN 61800-5-1 standard.
Electrical isolation is provided as shown in
The components described comply with both PELV and the
galvanic isolation requirements.
System Integration
Design Guide
MG16G202
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