Motor Connection - Danfoss FC 300 Design Manual

FC 300 Design Guide

Motor Connection

NB!
Motor cable must be screened/arm-
oured. If an unscreened/unarmoured
cable is used, some EMC requirements
are not complied with. For more infor-
mation, see EMC specifications in the
VLT AutomationDrive FC 300 Design
Guide.
See section General Specifications for correct di-
mensioning of motor cable cross-section and
length.
• Use a screened/armoured motor cable to
comply with EMC emission specifications.
If an unscreened/unarmoured cable is
used, some EMC requirements are not
complied with. For more information, see
EMC specifications in the VLT Automation-
Drive FC 300 Design Guide.
• Keep the motor cable as short as possible
to reduce the noise level and leakage cur-
rents.
• Connect the motor cable screen to both
the decoupling plate of the FC 300 and to
the metal housing of the motor.
• Make the screen connections with the
largest possible surface area (cable
clamp). This is done by using the supplied
installation devices in the FC 300.
• Screening of cables: Avoid installation
with twisted screen ends (pigtails). They
spoil the screening effect at higher fre-
quencies. 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.
• If it is necessary to split the screen to in-
stall a motor isolator or motor relay, the
screen must be continued with the lowest
possible HF impedance.
Screening of cables:
twisted screen ends (pigtails). They spoil the
screening effect at higher frequencies. If it is nec-
essary to break the screen to install a motor iso-
lator or motor contactor, the screen must be
continued at the lowest possible HF impedance.
How to Install
Avoid installation with
MG.33.B7.02 - VLT is a registered Danfoss trademark
Cable-length and cross-section:
cy converter has been tested with a given length
of cable and a given cross-section of that cable. If
the cross-section is increased, the cable capaci-
tance - and thus the leakage current - may in-
crease, and the cable length must be reduced
correspondingly.
Switching frequency:
ers are used together with LC filters to reduce the
acoustic noise from a motor, the switching fre-
quency must be set according to the LC filter in-
struction in Par. 14-01.
1. Fasten decoupling plate to the bottom of
FC 300 with screws and washers from the
accessory bag.
2. Attach motor cable to terminals 96 (U), 97
(V), 98 (W).
3. Connect to earth connection (terminal 99)
on decoupling plate with screws from the
accessory bag.
4. Insert plug connectors 96 (U), 97 (V), 98
(W) (up to 7.5 kW) and motor cable to
terminals labelled MOTOR.
5. Fasten screened cable to decoupling plate
with screws and washers from the acces-
sory bag.
Motor connection ≤ 7.5 kW IP 20 (A1, A2 and A3 enclo-
sures)
The frequen-
When frequency convert-
79