Danfoss VACON NX All-in-One Application Manual page 168

VACON® NX All-in-One
Application Guide
• P2.19 (Basic Application)
• P2.1.15 (Standard Application)
• P2.1.16 (Multi-Step Speed Control Application, Multi-Purpose Control Application)
Use this parameter to set the preset frequency reference when the preset frequencies function is used. Select the preset frequencies
with the digital input signals.
Parameter values are automatically limited to the maximum frequency (ID 102).
Note the use of TTF-programming method in the Multi-purpose Control Application. Because all digital inputs are programmable,
first assign two DINs for the Preset Speed functions (parameters ID 419 and ID 420).
10.7 (ID 107) Current Limit
Location in the menu:
• P2.5 (Basic Application)
• P2.1.5 (Standard Application, Local/Remote Control Application, Multi-Step Speed Control Application, PID Control Application,
Multi-Purpose Control Application, Pump and Fan Control Application)
Use this parameter to set the maximum motor current from the AC drive.
The range of values for the parameter is different for each enclosure size of the drive. When the current limit is changed, the stall
current limit (ID 710) is internally calculated to 90% of current limit.
When the current limit is active, the drive output frequency decreases.
The Motor Current Limit is not an overcurrent trip limit.
10.8 (ID 108) U/f Ratio Selection
Location in the menu: P2.6.3 (Standard Application, Local/Remote Control Application, Multi-Step Speed Control Application, PID
Control Application, Multi-Purpose Control Application, Pump and Fan Control Application)
Use this parameter to set the type of the U/f curve between zero frequency and the field weakening point.
Selec- Selection
tion name
num-
ber
0 Linear
1 Squared
2 Programma-
ble
3 Linear with
flux optimi-
zation
168 | Danfoss A/S © 2023.02
N O T I C E
Description
The voltage of the motor changes linearly as a function of the output frequency. The voltage changes
from the value of Zero Frequency Voltage (ID 606) to the value of Voltage at Field Weakening Point (ID
603) at a frequency set in Field Weakening Point Frequency (ID 602). Use this default setting if a differ-
ent setting is not necessary.
The voltage of the motor changes from the value of Zero Frequency Voltage (ID 606) to the value of
Field Weakening Point Frequency (ID 603) at a squared curve. The motor operates undermagnetized
below the field weakening point and produces less torque. Use the squared U/f ratio in applications
where the torque demand is in relation to the square of the speed, for example in centrifugal fans and
pumps.
It is possible to program the U/f curve with 3 different points: the zero frequency voltage (P1), the
midpoint voltage/ frequency (P2), and the field weakening point (P3). Use the programmable U/f
curve at low frequencies if it is necessary to have more torque. To find the optimal settings automati-
cally, use the identification run (ID 631).
The AC drive starts to search for the minimum motor current to save energy and to lower the motor
noise. Use it in applications such as fans and pumps.
Parameter Descriptions
AB296635287482en-000301 / DPD00903