50
MG.30.A7.02 - VLT
®
is a registered Danfoss trademark
With the VLT
®
3000 Series, all types of
3-phase asynchronous standard motors
can be used.
In general, small motors (220/380 V,
∆
/ )
are star-connected. Large motors are
delta-connected (380/660 V,
∆
/ ).
Motor connection
The factory setting will give clockwise
rotation when the output of the VLT
®
3000
Series is connected as follows:
Terminal 96 connected with U phase
Terminal 97 connected with V phase
Terminal 98 connected with W phase
The rotation direction can be changed by
swapping the two motor cable phases.
With the VLT
®
3000 Series controls, the
rotation direction can also be changed
using the “reverse” function.
VLT
®
3000 Series can control several
motors connected in parallel. If the motor
speeds must be different, motors of
different rated speeds must be applied.
The motor speed can be changed simul-
taneously and the ratio between the rated
motor speeds is maintained in the whole
range.
The total current consumed by the motors
may not exceed the maximum rated output
current I
VLT,N
of the VLT
®
3000 Series.
If motor sizes deviate considerably, prob-
lems may arise during start and at low
speed. This is due to the fact that small
motors have a relatively high ohmic resist-
ance in the stator, and therefore they
require more start voltage during start and
at low speed.
In systems with parallel motor operation,
the internal overcurrent protection cannot
be used as motor protection for the indi-
vidual motor, since the output current must
be programmed for the total motor current.
Additional motor protection should there-
fore be used, e.g. thermistors in each
motor (or individual thermal relay).
Direction of rotation
Parallel connection
of motors
Connection of motor
Y
Y
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