Danfoss VLT AQUA Design Manual page 104

5. How to Install
5.5.5. Parallel Connection of Motors
5
The frequency converter can control several parallel-connected motors.
The total current consumption of the motors must not exceed the rated
output current I for the frequency converter.
INV
NB!
When motors are connected in parallel, par. 1-02
tomatic Motor Adaptation (AMA)
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 electronic thermal relay (ETR) of the frequency converter cannot be
used as motor protection for the individual motor of systems with parallel-
connected motors. Provide further motor protection by e.g. thermistors
in each motor or individual thermal relays. (Circuit breakers are not suit-
able as protection).
104
Au-
cannot be used.
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MG.20.N3.02 - VLT is a registered Danfoss trademark
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VLT AQUA Drive Design Guide