VLT
®
4000 VT
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Motor connection
The motor must be connected to terminals 96,
97, 98. Ground to terminal 99.
Nos. 96, 97, 98
Motor voltage 0-100% of
U, V, W
line voltage.
No. 99
Ground connection.
See
Technical data
for correct sizing of cable
cross-sections.
All types of three-phase asynchronous standard
motors can be used with a VLT 4000 VT unit.
Small-size motors are normally star-connected.
(220/380 V,
/Y).
Large-size motors are delta-connected (380/660
V,
/Y). The correct connection and voltage can
be read from the motor nameplate.
NOTE
In older motors without phase coil insulation, a
LC filter should be fitted to the VLT AFD output.
See the Design Guide or contact Danfoss.
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Direction of IEC motor rotation
The factory setting is for clockwise rotationwith the VLT
frequency transformer output connected as follows.
Terminal 96 connected to U-phase
Terminal 97 connected to V-phase
Terminal 98 connected to W-phase
The direction of rotation can be changed by switching
two phases in the motor cable.
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Parallel coupling of motors
VLT 4000 VT is able to control several motors
connected in parallel. If the motors are to have
diffe-rent rpm values, the motors must have
different rated rpm values. Motor rpm is changed
simultaneously, which means that the ratio between
the rated rpm values is maintained across the range.
The total current consumption of the motors
is not to exceed the maximum rated output
current I
VLT,N
for the VLT AFD.
Problems may arise at the start and at low rpm values if
the motor sizes are widely different. This is because the
relatively high ohmic resistance in small motors calls for
a higher voltage at the start and at low rpm values.
In systems with motors connected in parallel, the
electronic thermal relay (ETR) of the VLT AFD cannot
be used as motor protection for the individual
motor. Consequently, additional motor protection
is required, such as thermistors in ground motor
(or individual thermal relays).
NOTE
Parameter 107
Automatic Motor Adaptation,
AMA
and
Automatic Energy Optimization, AEO
in parameter 101
Torque characteristics
cannot
be used motors are connected in parallel.
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Motor cables
See
Technical data
for correct sizing of motor
cable cross-section and length.
Always comply with national and local regulations
on cable cross-sections.
MG.40.A7.22 - VLT is a registered Danfoss trademark
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