Power Connections - Danfoss VLT HVAC Drive FC 100 Operating Instructions Manual

®
VLT HVAC DRIVE High Power
Operating Instruction
24 V external DC supply can be used as low-voltage supply to the control card and any option
cards installed. This enables full operation of the LCP (incl. parameter setting) without connection
to mains. Please note that a warning of low voltage will be given when 24 V DC has been con-
nected; however, there will be no tripping.

3.6.2. Power Connections

Cabling and Fusing
The power cable connections are situated as shown below. Dimensioning of cable cross section
must be done in accordance with the current ratings and local legislation. See the
section
For protection of the frequency converter the recommended fuses must be used or the unit must
be with built-in fuses. Recommended fuses can be seen in the tables in the fuses section. Always
ensure that proper fusing is made according to local regulation.
The mains connection is fitted to the mains switch if this is included.
See section
length.
Screening of cables:
Avoid installation with twisted screen ends (pigtails). They spoil the screening effect at higher
frequencies. If it is necessary to break the screen to install a motor isolator or motor contactor,
the screen must be continued at the lowest possible HF impedance.
Connect the motor cable screen to both the de-coupling plate of the frequency converter and to
the metal housing of the motor.
Use 24 V DC supply of type PELV to ensure correct galvanic isolation (type PELV) on
the control terminals of the frequency converter.
NB!
Cables General
All cabling must comply with national and local regulations on cable cross-sections
and ambient temperature. Copper (75°C) conductors are recommended.
for details.
NB!
Motor cable must be screened/armoured. If an unscreened/unarmoured cable is
used, some EMC requirements are not complied with. Use a screened/armoured
motor cable to comply with EMC emission specifications. For more information, see
EMC specifications
in the
General Specifications
MG.11.F1.02 - VLT ® is a registered Danfoss trademark
Design Guide
.
for correct dimensioning of motor cable cross-section and
3. How to Install
3
Specifications
45