2.3 Main Menu - Load and Motor - Group 1
2.3.1 General Settings, 1-0*
Define whether the frequency converter operates in open loop or closed loop.
1-00 Configuration Mode
Option:
Function:
[0] *
Open Loop
Motor speed is determined by applying a speed reference or by setting desired speed when in Hand
Mode.
Open Loop is also used if the frequency converter is part of a closed loop control system based on
an external PID controller providing a speed reference signal as output.
[3]
Closed Loop
Motor Speed will be determined by a reference from the built-in PID controller varying the motor
speed as part of a closed loop control process (e.g. constant pressure or flow). The PID controller
must be configured in par. 20-** or via the Function Setups accessed by pressing the [Quick Menus]
button.
NB!
This parameter cannot be changed when motor is running.
NB!
When set for Closed Loop, the commands Reversing and Start Reversing will not reverse the direction of the motor.
2.3.2 Motor Control Principle, 1-01
1-01 Motor Control Principle
Option:
Function:
Select the motor control principle.
[0]
U/f
[1] *
VVC+
1-03 Torque Characteristics
Option:
Function:
[0]
Constant Torque
For speed control of constant torque applications like axial pumps, positive displacement pumps and
blowers. Provides a voltage which is optimized for a constant torque load characteristic of the motor
in the entire speed range.
[1]
Variable torque
For speed control of centrifugal pumps and fans. Also to be used when controlling more than one
motor from the same frequency converter (e.g. multiple condenser fans or cooling tower fans).
Provides a voltage which is optimized for a squared torque load characteristic of the motor.
[2]
Auto energy optim. CT
For optimum energy efficient speed control of axial pumps, positive displacement (PD) pumps and
blowers. Provides a voltage which is optimized for a constant torque load characteristic of the motor
in the entire speed range but in addition the AEO feature will adapt the voltage exactly to the current
load situation, thereby reducing energy consumption and audible noise from the motor. To obtain
optimal performance, the motor power factor cos phi must be set correctly. This value is set in par.
14-43, Motor cos phi. The parameter has a default value which is automatically adjusted when the
motor data is programmed. These settings will typically ensure optimum motor voltage but if the
motor power factor cos phi requires tuning, an AMA function can be carried out using par. 1-29,
VLT
®
AQUA Drive Programming Guide
2 Parameter Description
MG.20.O4.02 - VLT
®
is a registered Danfoss trademark
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