Load And Motor - Danfoss VLT 2800 Manual

Load and Motor

Configuration
Selection of configuration and torque characteristics
has an effect on which parameters can be seen in the
display. If Open loop [0] is selected, all parameters re-
lating to PID regulation will be filtered out. This means
that the user only sees the parameters that are rele-
vant for a given application.
100 Configuration
(Configuration)
Value:
Speed control, open loop
(SPEED OPEN LOOP)
Speed control, closed loop
(SPEED CLOSED LOOP)
Process control, closed loop
(PROCESS CLOSED LOOP)
Function:
This parameter is used to select the configuration to
which the frequency converter is to be adapted. This
makes adaptation to a given application simple, since
the parameters not used in a given configuration are
hidden (not active).
Description of choice:
If Speed control, open loop [0] is selected, normal
speed control is obtained (without feedback signal)
with automatic load and slip compensation to ensure
a constant speed at varying loads. Compensations are
active, but may be disabled in parameter 134 Load
compensation and parameter 136 Slip compensation
as required.
If Speed control, closed loop [1] is selected, better
speed accuracy is obtained. A feedback signal must
be added, and the PID regulator must be set in pa-
rameter group 400 Special functions.
If Process control, closed loop [3] is selected, the in-
ternal process regulator is activated to enable precise
control of a process in relation to a given process sig-
nal. The process signal can be set to the relevant
process unit or as a percentage. A feedback signal
must be added from the process and the process reg-
ulator must be set in parameter group 400 Special
functions. Process closed loop is not active if a Devi-
ceNet card is mounted and Instance 20/70 or 21/71 is
chosen in parameter 904 Instance types.
= factory setting, () = display text, [] = value for use in communication via serial communication port
MG.27.E2.02 - VLT is a registered Danfoss trademark
101 Torque characteristic
(TORQUE CHARACT)
Value:
Constant torque
(Constant torque)
Variable torque low
(torque: low)
Variable torque medium
(torque: med)
Variable torque high
(torque: high)
Variable torque low with CT start
(VT LOW CT START)
Variable torque medium with CT start
(VT MED CT START)
[0]
Variable torque high with CT start
(VT HIGH CT START)
[1]
Special motor mode
(Special motor mode)
[3]
CT = Constant torque
Function:
This parameter enables a choice of principle for adap-
tation of the U/f ratio of the frequency converter to the
torque characteristic of the load. See par. 135 U/f ratio.
Description of choice:
If Constant torque [1] is selected, a load-dependent U/
f characteristic is obtained, in which output voltage and
output frequency are increased at increasing loads in
order to maintain constant magnetization of the motor.
Select Variable torque low [2], Variable torque medium
[3] or Variable torque high [4], if the load is square
(centrifugal pumps, fans).
Variable torque - low with CT start [5], - medium with
CT start [6] or high with CT start [7], are selected if you
need a greater breakaway torque than can be ach-
ieved with the three first characteristics.
NB!
Load and slip compensation are not active
if variable torque or special motor mode
have been selected.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
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