Power Connections; Grounding - Danfoss VLT HVAC Drive FC 102 Operating Instructions Manual

Electrical Installation

4.3 Power Connections

NOTICE
Cables–General Information
All cabling must comply with national and local
regulations on cable cross-sections and ambient
temperature. UL applications require 75 °C copper
conductors. For non-UL applications, 75 and 90 °C
4 4
copper conductors are thermally acceptable.
The power cable connections are situated as shown in
Illustration 4.2. Dimension cable cross-section in accordance
with the current ratings and local legislation. See
chapter 8.3.1 Cable lengths and cross-sections for details.
For protection of the frequency converter, use the
recommended fuses if there are no built-in fuses. Fuse
recommendations are provided in chapter 8.5 Fuses. Ensure
that proper fusing is made according to local regulation.
The mains connection is fitted to the mains switch, if
included.
3 Phase
power
input
Illustration 4.2 Power Cable Connections
NOTICE
To comply with EMC emission specifications, screened/
armoured cables are recommended. If an unscreened/
unarmoured cable is used, see chapter 4.7.3 Power and
Control Wiring for Unscreened Cables.
See chapter 8 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 breaking
the screen is necessary 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 to the metal housing
of the motor.
30
Operating Instructions
91 (L1)
92 (L2)
93 (L3)
95 PE
Danfoss A/S © Rev. 2014-07-29 All rights reserved.
Make the screen connections with the largest possible
surface area (cable clamp). Use 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
14-01 Switching Frequency.
Term. 96 97 98 99
no.
Motor voltage 0–100% of mains
1)
U V W PE voltage.
3 wires out of motor
U1 V1 W1 Delta-connected
1)
PE
W2 U2 V2 6 wires out of motor
Star-connected U2, V2, W2
U1 V1 W1 PE 1) U2, V2, and W2 to be interconnected
separately.
Table 4.1 Terminal Connections
1) Protective Earth Connection
Motor
U V W
2 2 2
U V W
1 1 1
FC
96 97 98
Illustration 4.3 Y and Delta Terminal Configurations

4.4 Grounding

Consider the following basic issues for electromagnetic
compatibility (EMC) during installation:
•
Safety grounding: The frequency converter has a
high leakage current and must be grounded
appropriately for safety reasons. Apply local
safety regulations.
•
High-frequency grounding: Keep the ground wire
connections as short as possible.
Connect the different ground systems at the lowest
possible conductor impedance. Keep the conductor as
short as possible and use the greatest possible surface area
for the lowest possible conductor impedance.
Motor
U V W
2 2 2
V W
U
1 1
1
FC
96 97 98
MG16I202