Power Connections - Danfoss VLT AutomationDrive FC 300 Design Manual

Electrical Installation

7.1.2 Power Connections

NOTICE
All cabling must comply with national and local
regulations on cable cross-sections and ambient
temperature. UL applications require 75 °C copper
conductors. Non-UL applications can use 75 °C and 90 °C
copper conductors.
The power cable connections are situated as shown in
Illustration 7.1. Dimensioning of cable cross section must
comply with the current ratings and local legislation. See
4.3 General Specifications for correct dimensioning of motor
cable cross-section and length.
For protection of the frequency converter, use the
recommended fuses unless the unit has built-in fuses.
Recommended fuses are listed in the Operating
Instructions. Ensure that proper fusing complies with local
regulations.
The mains connection is fitted to the mains switch if
included.
3 Phase
power
input
Illustration 7.1 Power Cable Connections
NOTICE
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 7.8 EMC-Correct
Installation.
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
contactor, continue the screen at the lowest possible HF
impedance.
Connect the motor cable screen to both the de-coupling
plate of the frequency converter and the metal housing of
the motor.
®
VLT AutomationDrive FC 300 Design Guide 90-1200 kW
91 (L1)
92 (L2)
93 (L3)
95 PE
MG34S202 - Rev. 2013-08-19
Make the screen connections with the largest possible
surface area (cable clamp) by using the 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
instructions in 14-01 Switching Frequency.
Term. 96 97 98 99
no.
U V W PE Motor voltage 0-100% of mains
1)
voltage.
3 wires out of motor
U1 V1 W1 Delta-connected
PE 1)
W2 U2 V2 6 wires out of motor
U1 V1 W1 PE Star-connected U2, V2, W2
1)
U2, V2, and W2 to be interconnected
separately.
Table 7.2 Motor Cable Connection
1)
Protected Earth Connection
NOTICE
In motors without phase insulation, paper or other
insulation reinforcement suitable for operation with
voltage supply, fit a sine-wave filter on the output of the
frequency converter.
Motor
U V W
2 2 2
U V W
1 1 1
FC
96 97 98
Illustration 7.2 Motor Cable Connection
Motor
U V W
2 2 2
V W
U
1 1
1
FC
96 97 98
161
7 7