Additional Motor Information; Motor Cable; Connection Of Multiple Motors - Danfoss VLT AutomationDrive FC 301 Design Manual

Electrical Installation

9.7 Additional Motor Information

9.7.1 Motor Cable

All types of 3-phase asynchronous standard motors can be
used with a frequency converter unit. The factory setting is
for clockwise rotation with the frequency converter output
connected as follows.
Motor
U V
2
U V
1
FC
96 97
Motor
9 9
U V
2
U V
1
FC
96 97
Illustration 9.49 Terminal Connection for Clockwise and
Counter-clockwise Rotation
The direction of rotation can be changed by switching 2
phases in the motor cable or by changing the setting of
4-10 Motor Speed Direction.
Motor rotation check can be performed using 1-28 Motor
Rotation Check and following the steps shown in the
display.
140
W
2 2
W
1 1
98
W
2 2
W
1 1
98
®
VLT AutomationDrive FC 301/FC 302 Design Guide, 0.25-75 kW

9.7.2 Connection of Multiple Motors

NOTICE
Problems may arise at start and at low RPM values if
motor sizes are widely different because small motors'
relatively high ohmic resistance in the stator calls for a
higher voltage at start and at low RPM values.
The frequency converter can control several parallel-
connected motors. When using parallel motor connection
observe the following:
•
•
•
•
•
•
•
NOTICE
When motors are connected in parallel, 1-02 Flux Motor
Feedback Source cannot be used, and 1-01 Motor Control
Principle must be set to [0] U/f.
Illustration 9.50 Common Joint Connection for Short Cable
Lengths
MG33BF02 - Rev. 2013-12-20
+
VCC mode may be used in some applications.
The total current consumption of the motors
must not exceed the rated output current I
the frequency converter.
Do not use common joint connection for long
cable lengths, see Illustration 9.51.
The total motor cable length specified in
Table 5.2, is valid as long as the parallel cables are
kept short (less than 10 m each), see
Illustration 9.53 and Illustration 9.54.
Consider voltage drop across the motor cable,
see Illustration 9.54.
For long parallel cables, use LC filter, see
Illustration 9.54.
For long cables without parallel connection, see
Illustration 9.55.
for
INV