Select
[1] OK - same direction
if the motor shaft is only able
to rotate in the same direction when cutting in. Select
[1]
OK - same direction
if [0] Clockwise only has been selected
in
parameter 200 Output frequency range
.
Select
[2] OK - both directions
if the motor is able to rotate
in both directions when cutting in.
Select
[3] DC brake and start
if the adjustable frequency
drive 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
are enabled. In the case of higher
windmilling (rotating motor) effects, the adjustable
frequency drive is not able to catch a rotating motor
without selecting
[3] DC brake and start
.
Limitations:
•
Too low inertia leads to load acceleration, 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.
•
Flying start does not work at lower values than
250 RPM.
451
Speed PID feedforward factor
Value:
0 - 500%
100%
Function:
This parameter is only active if in
parameter 100 Configu-
ration
the selection made is
Speed regulation, closed loop
.
The FF function sends a larger or smaller part of the
reference signal outside the PID controller in such a way
that the PID controller only has an influence on part of the
control signal. Any change to the set point has a direct
effect on the motor speed. The FF factor provides high
dynamism when changing the set point and less
overswing.
Description of choice:
The required % value can be selected in the interval f
MIN
-
f
MAX
. Values over 100% are used if the set point variations
are only small.
452
Controller range
Value:
0 - 200%
10%
Function:
This parameter is only active if [1] Speed control, closed
loop has been selected in
parameter 100 Configuration
.
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 variations
is less during initial tuning.
455
Frequency range monitor
Value:
Disable
[0]
Enable
[1]
Function:
Use this parameter to turn off warning
33 Out of frequency
range
in the display in process control closed loop. This
parameter does not affect the extended status word.
Description of choice:
Select
[1] Enable
to enable the readout in the display if
warning
33 Out of frequency range
occurs. Select
[0] Disable
to disable the readout in the display if warning
33 out of
frequency range
occurs.
456
Brake Voltage Reduce
Value:
0-25 V if 200 V device
0
0-50 V if 400 V device
0
Function:
The user sets the voltage by which the level for resistor
braking is reduced. It is only active when resistor in
parameter 400 Brake function
is selected.
Description of choice:
The greater the reduction value, the faster the reaction to
a generator overload. Should only be used if there are
problems with overvoltage in the intermediate circuit.
Programming
Design Guide
100
Danfoss A/S © Rev. May/2014 All rights reserved.
MG27E402
4
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