Danfoss VLT AutomationDrive FC 300 Design Guide

7.4.2 Parallel Connection of Motors
The adjustable frequency drive can control several motors connected in parallel. When using parallel motor connection,
observe the following points:
•
Run applications with parallel motors in U/F mode (volts per hertz).
•
VCC
plus
mode may be used in some applications.
•
Total current consumption of motors must not exceed the rated output current I
INV
for the adjustable frequency
drive.
•
Problems may arise at start and at low RPM if motor sizes are widely different because the small motors’ relatively
high ohmic resistance in the stator demands a higher voltage at start and at low RPM.
•
The electronic thermal relay (ETR) of the adjustable frequency drive cannot be used as motor protection. Provide
further motor protection by including thermistors in each motor winding or individual thermal relays.
•
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 Special motor characteristics (U/f).
Electrical Installation Design Guide
220 Danfoss A/S © Rev. 2014-02-10 All rights reserved. MG34S222
77

Danfoss VLT AutomationDrive FC 300 Specifications

General

Brand	Danfoss
Model	VLT AutomationDrive FC 300
Category	DC Drives
Language	English