Relay Output; Parallel Connection Of Motors - Danfoss VLT AutomationDrive FC 300 Design Manual

FC 300 Design Guide

Relay Output

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Relay 1
Terminal 01: common
•
Terminal 02: normal open 240 V AC
•
Terminal 03: normal closed 240 V AC
•
Relay 2 (FC 302 only)
Terminal 04: common
•
Terminal 05: normal open 400 V AC
•
Terminal 06: normal closed 240 V AC
•
Relay 1 and relay 2 are programmed in par.
5-40, 5-41, and 5-42.
Additional relay outputs by using option
module MCB 105.

Parallel Connection of Motors

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The frequency converter can control several
parallel-connected motors. The total current
consumption of the motors must not exceed the
rated output current I
INV
This is only recommended when U/f is
selected in par. 1-01.
NB!:
When motors are connected in parallel,
par. 1-02 Automatic Motor Adaptation
(AMA) cannot be used, and par. 1-01
Motor Control Principle must be set to Special
motor characteristics (U/f).
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 suitable as protection).
102
How to Install
for the frequency converter.
MG.33.B4.02 - VLT is a registered Danfoss trademark