Frequency Inverter DF51... - Moeller.com.tr

04/07 AWB8230-1541GB Monitoring functionsMonitoring functionsThe functions described here are used to monitor the powersection for overload and to protect the connected motor.HOLLimiting motor currentIf the output current (= motor current, I M ) exceeds the value setwith PNU b022 (b222), the output frequency (rotating fieldfrequency) is reduced. You can set the deceleration time constantwith PNU b023 (b223).h Attention!Note that the current limit cannot prevent a fault messageand shutdown due to a sudden overcurrent (e.g. causedby a short-circuit).Figure 119:0 – 10 VI LVL = 10 – 150 % I eConnection of potentiometer to the external overloadlimitation (resistance value of potentiometer between2kO and 10 kO; re<strong>com</strong>mended value about 5 kO)With an analog 0 to +10 V reference value signal (terminal O-L)you can adjust current limitation (I LVL ) in a range from 10 to 150 %of the rated device current (I e ). The change of the analog currentlimitation is delayed by 100 to 200 ms by the “sampling time” a(internal process time of CPU and controller).I M10 Vb0220150 %tfaa10 %0100...200 ms atFigure 118: Current limit enableda Deceleration time constant (PNU b023/b223)b022 (b222): Tripping current limitI M :Motor currenttFigure 120: Variable overload limitationa Sampling time (internal processing time of CPU and controller)With PNU b028 (b228) you can match the current limitation to theprocess. The reference frequency must be provided digitallythrough:• Digital inputs 1 to 5:– Fixed frequency (f1 to f 15 )– Electronic motor potentiometer (UP, DWN)• Keypad– Fixed frequency PNU A020– Electronic motor potentiometer: Arrow keys Í and Ú.113