Danfoss VT2800 Series User Manual

VLT
®
2800 Series
feedback signal varies by a higher freque ncy than 1.6
Hz, it will be dampened by the lowpass filter.
445 Flying start
(FLYINGSTART)
Value:
✭Off (DISABLE)
[0]
OK - same direction
(OK-SAME DIRECTION)
[1]
OK - both directions
(OK-BOTH DIRECTIONS)
[2]
DC brake and start
(DC-BRAKE BEF. START)
[3]
Function:
This function makes it possible to ’catch’ arotating
motor shaft, which is no longer controlled by the
frequency converter, e.g. because of a mains
drop-out. The funct ion is act ivated each t ime a start
command is enabled. For the frequency converter
to be able to ’catch’ the rotating motor shaft, the
motor speed must be lower than the frequency
that corresponds to the frequency in parameter
202 Output frequenc y, high limit, f
MAX
.
Description of choice:
Select Disable [0] if this function is not required.
Select OK - same direction [1] if the motor shaft
is only ab le to rotate in the same direction when
cutting i n. OK - same direct ion [1] should be
selected if in parameter 200 Output frequency range
a selection has been of Clockwise only .
Select OK - both directions [2] if the mo tor is able
to rotate in both directions when cutting in.
Select DC brake and start [3] if the frequency converter
is to be able to brake the motor using the DC brake
first, followed by start. It is assumed that parameters
126-127/132 DC brake a re enabled. In the case
of higher ’Wind m illi ng’ (rotating m otor) effects, the
frequency converter is not able to ’catch ’ arotating
motor without selecting DC brake and start .
Limitations:
- Too low inertia will lead to load accelerat ion, which
can be dangerous or prevent correct catching of a
rotating motor. Use the DC brake instead.
- If the load is driven, e.g. by ’Windmilling’
(rotating motor) effects, the unit may cut
out because of overvoltage.
- Fly ing start does not work at lower v alues
than 250 rpm.
451 Speed PID feedforward factor
(FEEDFORWARD FACT)
Value:
0 - 500 %
✭ 100 %
Function:
This parameter is only active if in parameter 100
Configuration the selection made is Speed regulation,
closed loop. The FF funct i on sends a larger or sma ller
part of the reference signal outside the PID controller
in such a way that the PID controller only has an
influence on pa rt of the control signal. Any change
to the set point will thus have a direct effect on the
motor speed. The FF factor provides high dynamism
when changing the set point and less ove rswing.
Description of choice:
The required % value can be selected in the interval
f
MIN
-f
MAX
. Values over 100 % are used if the
set p oint variations are only small.
452 Controller range
(PID CONTR. RANGE)
Value:
0 - 200 %
✭ 10 %
Function:
This parameter is only active if in parameter
100 Configurat ion the selection made is Speed
regulation, closed loop.
The controller range (bandwidth) limits the output from
the PID controller as a % of motor frequency f
M,N
.
Description of choice:
The required % value can be selected for motor
frequency f
M,N
. If the controller range is reduced the
speed variat ions will be le ss during initial tuning.
456 Brake Voltage Reduce
(BRAKE VOL REDUCE)
Value:
0 - 25 V if 200V devic e
✭ 0
0 - 50 V if 400V devic e
✭ 0
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.E9.02 - VLT is a registered Danfoss trademark
106

Danfoss VT2800 Series Specifications

General

Brand	Danfoss
Model	VT2800 Series
Category	Controller
Language	English