Motor Connection - Danfoss VLT AutomationDrive FC 301 Design Manual

Electrical Installation

9.4 Motor Connection

WARNING
INDUCED VOLTAGE
Induced voltage from output motor cables that run
together can charge equipment capacitors even with the
equipment turned off and locked out. Failure to run
output motor cables separately or use screened cables
could result in death or serious injury.
•
run output motor cables separately, or
•
use screened cables
Motor Connection
NOTICE
To comply with EMC emission specifications, screened/
armoured cables are required. For more information, see
chapter 5.2.1 EMC Test Results and Illustration 3.3.
See chapter 6.2 General Specifications for correct
dimensioning of motor cable cross-section and length.
9 9
Term. 96 97
no.
U V
U1 V1 W1
W2 U2 V2
U1 V1 W1
Table 9.17 Terminal Descriptions
1)
Protected Ground Connection
Motor
U V
2 2
U V
1 1
FC
96 97
Illustration 9.29 Star and Delta Connections
132
VLT
98 99
W 1) Motor voltage 0-100% of mains
PE
voltage.
3 wires out of motor
Delta-connected
PE 1)
6 wires out of motor
1) Star-connected U2, V2, W2
PE
U2, V2 and W2 to be intercon-
nected separately.
Motor
W
U V
2 2 2
V
U
W
1
1 1
FC
98
96 97
®
AutomationDrive FC 301/FC 302 Design Guide, 0.25-75 kW
NOTICE
In motors without phase insulation paper or other
insulation reinforcement suitable for operation with
voltage supply (such as a frequency converter), fit a Sine-
wave filter on the output of the frequency converter.
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.
NOTICE
Strip a piece of the motor cable to expose the screen
behind the cable clamp, AND connect the ground
connection to terminal 99.
Connect the motor cable screen to both the decoupling
plate of the frequency converter 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 frequency converter.
If it is necessary to split the screen to install a motor
isolator or motor relay, the screen must be continued with
the lowest possible HF impedance.
Cable-length and cross-section
The frequency 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 capacitance - and
thus the leakage current - may increase, and the cable
length must be reduced correspondingly. Keep the motor
cable as short as possible to reduce the noise level and
leakage currents.
Switching frequency
When frequency converters are used with Sine-wave filters
W to reduce the acoustic noise from a motor, the switching
2
frequency must be set according to the Sine-wave filter
instruction in 14-01 Switching Frequency.
W
1
1. Fasten decoupling plate to the bottom of the
frequency converter with screws and washers
from the accessory bag.
2. Attach motor cable to terminals 96 (U), 97 (V), 98
98
(W).
3. Connect to ground 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 accessory bag.
MG33BF02 - Rev. 2013-12-20