Danfoss FC 300 Design Manual page 158

8 Electrical Installation
NB!
The 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
tions
in the
See section General Specifications
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.
8
Make the screen connections with the largest possible surface area (cable clamp). This is done by using the supplied installation devices within the
frequency converter.
Cable-length and cross-section:
The frequency converter has been EMC tested with a given length of cable. Keep the motor cable as short as possible to reduce the noise level and
leakage currents.
Switching frequency:
When frequency converters are used together with Sine-wave filters to reduce the acoustic noise from a motor, the switching frequency must be set
according to the instruction in par. 14-01
Term. no. 96
U
U1
W2
U1
1) Protected Earth Connection
158
Design Guide
.
for correct dimensioning of motor cable cross-section and length.
Switching Frequency
.
97 98 99
V W
PE 1)
V1 W1
PE 1)
U2 V2
V1 W1 PE 1)
MG.33.BC.02 - VLT
Motor voltage 0-100% of mains voltage.
3 wires out of motor
Delta-connected
6 wires out of motor
Star-connected U2, V2, W2
U2, V2 and W2 to be interconnected separately.
NB!
In motors without phase insulation paper or other in-
sulation reinforcement suitable for operation with volt-
age supply (such as a frequency converter), fit a Sine-
wave filter on the output of the frequency converter.
® is a registered Danfoss trademark
FC 300 Design Guide
EMC specifica-