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.
Use 24 V DC supply of type PELV to ensure correct galvanic isolation (type PELV) on
the control terminals of the frequency converter.
3.5.2. Power Connections
Cabling and Fusing
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.
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
Specifications
section
for details.
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.
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
Design Guide
.
See section
General Specifications
for correct dimensioning of motor cable cross-section and
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.
3. How to Install
VLT
®
Automation Drive FC 300
Operating Instructions High Power
48
MG.33.U1.02 - VLT
®
is a registered Danfoss trademark
3
