10 Parameter description
On the next pages you can find the descriptions of certain parameters. The
descriptions have been arranged according to parameter group and number.
(Control panel: Menu PAR
This parameter determines the maximum motor current from the frequency
converter. To avoid motor overload, set this parameter according to the rated
current of the motor. The current limit is equal to (1.5 × I
Motor control mode
With this parameter the user can select the motor control mode. The selec-
0 = Frequency control:
Drive frequency reference is set to output frequency without slip compensation.
Motor actual speed is finally defined by motor load.
1 = Open loop speed control:
Drive frequency reference is set to motor speed reference. The motor speed re-
mains the same regardless of motor load. Slip is compensated.
Application manual HVAC232/402 | Document 27-652 | Issue ENG06 | 2019-08-07
U / f ratio
There are three selections for this parameter:
) by default.
0 = Linear:
The voltage of the motor changes linearly with the frequency in the constant flux
area from 0 Hz to the field weakening point (FWP) where the field weakening point
voltage (FWP) is supplied to the motor. Linear U/f ratio should be used in constant
torque applications. See the graphic below.
This default setting should be used if there is no special need for another set-
1 = Square:
The voltage of the motor changes following a squared curve form with the fre-
quency in the area from 0 Hz to the field weakening point where the field weaken-
ing point voltage is also supplied to the motor. The motor runs under magnetised
below the field weakening point and produces less torque, power losses and elec-
tromechanical noise. Squared U/f ratio can be used in applications where torque
demand of the load is proportional to the square of the speed, e.g. in centrifugal
fans and pumps.
voltage of the motor
Fig. 43. Linear and squared change of motor voltage
of the motor