Frequency Bypass; Motor Preheat; Four Programmable Set-Ups; Dynamic Braking - Danfoss VLT AutomationDrive FC 301 Series Design Manual

Product Features

4.2.8 Frequency Bypass

In some applications, the system may have operational
speeds that create a mechanical resonance. This can
generate excessive noise and possibly damage mechanical
components in the system. The adjustable frequency drive
has four programmable bypass-frequency bandwidths.
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These allow the motor to step over speeds which induce
system resonance.

4.2.9 Motor Preheat

To preheat a motor in a cold or damp environment, a
small amount of DC current can be trickled continuously
into the motor to protect it from condensation and a cold
start. This can eliminate the need for a space heater.

4.2.10 Four Programmable Set-ups

The adjustable frequency drive has four set-ups which can
be independently programmed. Using multi-setup, it is
possible to switch between independently programmed
functions activated by digital inputs or a serial command.
Independent set-ups are used, for example, to change
references, or for day/night or summer/winter operation, or
to control multiple motors. The active set-up is displayed
on the LCP.
Set-up data can be copied from adjustable frequency drive
to adjustable frequency drive by downloading the
information from the removable LCP.

4.2.11 Dynamic Braking

Dynamic Brake is established by:
•
Resistor brake
A brake IGBT keeps the overvoltage under a
certain threshold by directing the brake energy
from the motor to the connected brake resistor
(2-10 Brake Function = [1]).
•
AC brake
The brake energy is distributed in the motor by
changing the loss conditions in the motor. The
AC brake function cannot be used in applications
with high cycling frequency since this overheats
the motor (2-10 Brake Function = [2]).
•
DC brake
An overmodulated DC current added to the AC
current works as an eddy current brake (2-02 DC
Braking Time ≠ 0 s).
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Design Guide
Rev. 2014-04-04 All rights reserved. MG33BF22