FR-A701 INSTRUCTION MANUAL (Applied) - Automation Systems ...

4PARAMETERS4.25.7 Regeneration avoidance function (Pr. 665, Pr. 882 to Pr. 886)(1) What is regeneration avoidance function? (Pr. 882, Pr. 883)Special operation and frequency controlThis function detects a regenerative status and increases the frequency to avoid the regenerative status.• Possible to avoid regeneration by automatically increasing the frequency and continue operation if the fanhappens to rotate faster than the set speed due to the effect of another fan in the same duct.ParameterNumber882883884885886665NameRegenerationavoidance operationselectionRegenerationavoidance operationlevelRegenerationavoidance atdecelerationdetection sensitivityRegenerationavoidancecompensationfrequency limit valueRegenerationavoidance voltagegainRegenerationavoidance frequencygain200Vclass400VclassInitialValue006Hz380VDC/760VDCSettingRangeDescription0 Regeneration avoidance function invalid1 Regeneration avoidance function is always valid2300 to800VRegeneration avoidance function is valid only during a constantspeed operationSet the bus voltage level at which regeneration avoidanceoperates. When the bus voltage level is set to low, overvoltageerror will be less apt to occur. However, the actual decelerationtime increases. The set value must be higher than the powersupply voltage × 2.0 Regeneration avoidance by bus voltage change ratio is invalid1 to 5100% 0 to 200%100% 0 to 200%Set sensitivity to detect the bus voltage change ratioSetting 1 5Detection sensitivity low high0 to 10HzSet the limit value of frequency which rises at activation ofregeneration avoidance function.9999 Frequency limit invalidAdjust responsiveness at activation of regeneration avoidance.A larger setting will improve responsiveness to the bus voltagechange. However, the output frequency could becomeunstable. When vibration is not suppressed by decreasing thePr. 886 setting, set a smaller value in Pr. 665.⋅ When the regenerative status is serious, the DC bus voltage rises and an overvoltage fault (E. OV) may occur.When this bus voltage rise is detected and the bus voltage level reaches or exceeds Pr. 883, increasing thefrequency avoids the regenerative status.⋅ For regeneration avoidance operation, you can select whether it is always activated or activated only at a constantspeed.Regeneration avoidance operationexample for accelerationBus voltage(VDC)Outputfrequency(Hz)Pr. 883TimeDuring regeneration Timeavoidance function operationRegeneration avoidance operationexample for constant speedBus voltage(VDC)Outputfrequency(Hz)Pr. 883TimeDuring regenerationavoidance function operationTimeBus voltage(VDC)Outputfrequency(Hz)Regeneration avoidance operationexample for decelerationPr. 883During regenerationavoidance function operationTimeTime⋅ Setting Pr. 882 to "1, 2" validates the regeneration avoidance function.REMARKS⋅ The inclination of the frequency increased or decreased by the regeneration avoidance function changes depending on theregenerative status.⋅ The DC bus voltage of the inverter is normally about 2 times greater than the input voltage.When the input voltage is 220VAC (440VAC), the bus voltage is about 311VDC (622VDC).However, it varies with the input power supply waveform.⋅ The Pr. 883 setting should be kept higher than the DC bus voltage level. Otherwise, the regeneration avoidance function isalways on even if the non-regeneration status and the frequency increases.⋅ While overvoltage stall ( ) is activated only during deceleration and stops the decrease in output frequency, the regenerationavoidance function is always on (Pr. 882 = 1) or activated only during a constant speed (Pr. 882 = 2) and increases the frequencyaccording to the regeneration amount.351