Motor Connection - Danfoss VLT FC 102 Series Design Manual

Electrical Installation
U
V W
Figure 6.13 AC Line Input Connection Enclosure Type C4
(IP20).
Usually the power cables for line power are non-shielded
cables.

6.1.4 Motor Connection

NOTICE!
To comply with EMC emission specifications, shielded/
armored cables are required. For more information, see
chapter 2.9.2 EMC Test Results.
See chapter 9 General Specifications and Troubleshooting for
correct dimensioning of motor cable cross-section and
length.
Shielding of cables:
Avoid installation with twisted shield ends (pigtails). They
spoil the shielding effect at higher frequencies. If it is
necessary to break the shield to install a motor isolator or
motor contactor, the shield must be continued at the
lowest possible HF impedance.
Connect the motor cable shield to both the decoupling
plate on the adjustable frequency drive and to the metal
housing on the motor.
Make the shield connections with the largest possible
surface area (cable clamp). This is done by using the
supplied installation devices in the adjustable frequency
drive.
If it is necessary to split the shield to install a motor
isolator or motor relay, continue the shield with the lowest
possible HF impedance.
MG11BC22
Design Guide
Cable length and cross-section
The adjustable frequency drive 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,
thereby requiring that the cable length is reduced
accordingly. Keep the motor cable as short as possible to
reduce the noise level and leakage currents.
Switching frequency
When adjustable frequency drives are used with sine-wave
filters to reduce the acoustic noise from a motor, the
switching frequency must be set according to the sine-
wave filter instruction in 14-01 Switching Frequency.
1.
2.
3.
4.
5.
All types of three-phase asynchronous standard motors can
be connected to the adjustable frequency drive. Normally,
small motors are star-connected (230/400 V, Y). Large
motors are normally delta-connected (400/690 V, Δ). Refer
to the motor nameplate for correct connection mode and
voltage.
Procedure
1.
2.
3.
4.
5.
Danfoss A/S © Rev. 06/2014 All rights reserved.
Fasten decoupling plate to the bottom of the
adjustable frequency drive with screws and
washers from the accessory bag.
Attach motor cable to terminals 96 (U), 97 (V),
98 (W).
Connect to ground connection (terminal 99) on
decoupling plate with screws from the accessory
bag.
Insert plug connectors 96 (U), 97 (V), 98 (W)
(up to 10 hp [7.5 kW]) and motor cable to
terminals labeled MOTOR.
Fasten shielded cable to the decoupling plate
with screws and washers from the accessory bag.
Strip a section of the outer cable insulation.
Position the stripped wire under the cable clamp
to establish mechanical fixation and electrical
contact between cable shield and ground.
Connect ground wire to the nearest grounding
terminal in accordance with grounding
instructions.
Connect the three-phase motor wiring to
terminals 96 (U), 97 (V), and 98 (W), see
Figure 6.14.
Tighten terminals in accordance with the
information provided in chapter 6.1.1 Torque.
6 6
97