VLT ® 2900 Series 1. Use the factory settings of R S which the fre- quency converter itself chooses on the basis of the motor nameplate data. Function: It is possible to optimise the resonance damping in CT mode. The grade of the influence is adjusted in this parameter. The value may be set between 0% (OFF) and 100%. 100% corresponds to 50% reduction of U/F ratio. Default value is OFF. 2. The value is stated by the motor supplier. 3. The value is obtained through manual meas- urements: R S can be calculated by measur- ing the resistance R PHASE-PHASE between two phase terminals.
Where R PHASE-PHASE is low- er than 1-2 Ohms (typical for motors > 5.5 kW, 400 V), a special Ohm-meter should be used (Thomson-bridge or similar). R S = 0.5 x R PHASE-PHASE . Internal settings (fixed): The resonance filter is active from 10% of nominal speed and above. In this case 5Hz and above. Speed to go from 0 to nominal flux level: 500ms Speed to go from nominal to 0 flux level: 500ms 4. R S is set automatically when AMT has been completed. See parameter 107 Auto motor adaption. Description of functionality: The filter monitors the active motor current and changes the motor voltage according to the figure be- low. The filter reacts on levels referring to the nominal motor current.
0.00 - X,XX Ω Depends on choice of motor After setting of parameters 102-106 Nameplate data , a number of adjustments of various parameters are made automatically, including stator reactance X S . The shaft performance can be improved by fine-tuning R S and X S , see procedure below. X S can be set as follows: 1. The value is stated by the motor supplier. 2. The value is obtained through manual meas- urements X S is obtained by connecting a mo- tor to mains and measuring the phase-phase voltage U M and the idle current φ . If the active motor current is below 10%, the motor voltage will be decreased by the speed mentioned above until the voltage reaches the setting for Par. 117.
If the active motor current comes over 20% the voltage will be increased by the above mentioned speed. If the active motor current reaches 40% the motor voltage will be increased immediately to normal motor voltage. The reduction in motor voltage depends on the pa- rameter 117 setting. U M 3 Ч I ϕ − X L 2 X s = X L : See parameter 142. 3. Use the factory settings of X S which the fre- quency converter itself chooses on the basis of the motor nameplate data. Description of choice: Set the grade of Motor current [Imact] influence on the U/F ratio between 0% (OFF) and 100%. 100% corre- sponds to 50% reduction of U/F ratio. Default value is OFF.
OFF - 100% [OFF - 100] OFF % [OFF] = factory setting, () = display text, [] = value for use in communication via serial communication port 22 MG.29.A3.02 - VLT ® is a registered Danfoss trademark 109 Stator reactance XS (STATOR REACTANCE) Value: Function: Description of choice: 117 Resonance damping (resonance damping) Value: