Danfoss VLT 2800 Design Guide

4.5 Special Functions
400 Brake function
Value:
Off (off) [0]
Resistor brake
(Resistor) [1]
AC brake (AC Brake) [4]
Load sharing (load sharing) [5]
Factory setting depends on unit type.
Function:
[1] Resistor brake
is selected if the adjustable frequency
drive has an integral brake transistor and brake resistor is
connected to terminals 81, 82. A higher intermediate
circuit voltage is permitted during braking (generated
operation) when a brake resistor is connected.
[4] AC brake can be selected to improve braking without
using brake resistors. Note that [4] AC brake is not as
effective as [1] Resistor brake.
Description of choice:
Select [1] Resistor brake if a brake resistor is connected.
Select [4] AC brake if short-term generated loads occur. See
parameter 144 Gain AC brake to set the brake.
Select [5] Load sharing if this is used.
NOTICE
A change of selection does not become active until the
mains voltage has been disconnected and reconnected.
405 Reset function
Value:
Manual reset (manual reset) [0]
Automatic reset x 1
(AUTOMATIC x 1) [1]
Automatic reset x 3
(AUTOMATIC x 3) [3]
Automatic reset x 10
(AUTOMATIC x 10) [10]
Reset at power-up
(RESET AT POWER UP) [11]
Function:
Select whether reset and restart after a trip are to be
manual, or whether the adjustable frequency drive is to be
reset and restarted automatically. Furthermore, it is
possible to select the number of times a restart is to be
attempted. The time between each attempt is set in
parameter 406 Automatic restart time.
Description of choice:
If [0] Manual reset is selected, reset is to be carried out via
the [STOP/RESET] key, a digital input or serial communi-
cation. If the adjustable frequency drive is to carry out an
automatic reset and restart after a trip, select data value [1]
Automatic reset x 1, [3] Automatic reset x 3 or [10] Automatic
reset x 10.
If
[11] Reset at power-up is selected, the adjustable
frequency drive carries out a reset if there has been a fault
in connection with the mains failure.
WARNING
The motor may start without warning.
406 Automatic restart time
Value:
0 - 1800
5
Function:
This parameter allows setting of the time from tripping
until the automatic reset function begins. It is assumed
that automatic reset has been selected in parameter 405
Reset function.
Description of choice:
Set the required time.
409
Trip delay overcurrent, I
LIM
Value:
0 - 60 (61=OFF)
OFF
Function:
When the adjustable frequency drive registers that the
output current has reached the current limit I
LIM
(parameter
221 Current limit) and remains there for the preset time, it
is disconnected. Can be used to protect the application,
like the ETR protects the motor if selected.
Description of choice:
Select how long the adjustable frequency drive should
maintain the output current at the current limit I
LIM
before
it disconnects. At OFF, parameter 409 Trip delay overcurrent,
I
LIM
is not working, i.e. disconnection does not take place.
411
Switching frequency
Value:
3000 - 14000 Hz (VLT 2803 - 2875)
4500 Hz
3000 - 10000 Hz (VLT 2880 - 2882)
4500 Hz
Function:
The set value determines the switching frequency of the
inverter. If the switching frequency is changed, this may
help to minimise possible acoustic noise from the motor.
Description of choice:
When the motor is running, the switching frequency is
adjusted in parameter 411 Switching frequency until the
frequency has been obtained at which the motor is as low-
noise as possible.
WARNING
The output frequency of the adjustable frequency drive
can never assume a value higher than 1/10 of the
switching frequency.
Programming Design Guide
92 Danfoss A/S © Rev. May/2014 All rights reserved. MG27E402
44

Danfoss VLT 2800 Specifications

General

Brand	Danfoss
Model	VLT 2800
Category	DC Drives
Language	English