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Special operation and frequency control
4
PARAMETERS
4.21.3 Regeneration avoidance function (Pr. 665, Pr. 882 to Pr. 886)
(1) What is regeneration avoidance function? (Pr. 882, Pr. 883)
⋅ When the regeneration 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 the
frequency avoids the regeneration status.
⋅ The regeneration avoidance operation, you can select whether it is always activated or activated only a constant speed.
⋅ Setting Pr. 882 to "1, 2" validates the regeneration avoidance function.
This function detects a regeneration status and increases the frequency to avoid the regeneration status.
Possible to avoid regeneration by automatically increasing the frequency and continue operation if the fan
happens to rotate faster than the set speed due to the effect of another fan in the same duct.
Parameter
Number
Name Initial Value
Setting
Range
Description
882
Regeneration
avoidance operation
selection
0
0 Regeneration avoidance function invalid
1 Regeneration avoidance function valid
2
Regeneration avoidance function is valid only during a
constant speed operation
883
Regeneration
avoidance operation
level
200V
class
380VDC
300 to 800V
Set the bus voltage level at which regeneration
avoidance operates. When the bus voltage level is set to
low, overvoltage error will be less apt to occur. However,
the actual deceleration time increases. The set value
must be higher than the power supply voltage × .
400V
class
760VDC
884
Regeneration
avoidance at
deceleration
detection sensitivity
0
0
Regeneration avoidance by bus voltage change ratio is
invalid
1 to 5
Set sensitivity to detect the bus voltage change ratio
Setting 1 5
Detection sensitivity low high
885
Regeneration
avoidance
compensation
frequency limit value
6Hz
*1
0 to 30Hz
Set the limit value of frequency which rises at activation
of regeneration avoidance function.
9999 Frequency limit invalid
886
Regeneration
avoidance voltage gain
100% 0 to 200%
Adjust responsiveness at activation of regeneration
avoidance. A larger setting will improve responsiveness
to the bus voltage change. However, the output
frequency could become unstable. When vibration is not
suppressed by decreasing the Pr. 886 setting, set a
smaller value in Pr. 665.
665
Regeneration
avoidance frequency
gain
100% 0 to 200%
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 201)
...............Specifications differ according to the date assembled. Refer to page 378 to check the SERIAL number.
*1 Performing IPM parameter initialization changes the settings. (Refer to page 80)
REMARKS
⋅ The inclination of the frequency increased or decreased by the regeneration avoidance function changes depending on the
regeneration status.
⋅ The DC bus voltage of the inverter is normally about times greater than the input voltage.
When the input voltage is 220VAC, the bus voltage is about 311VDC.
When the input voltage is 440VAC, the bus voltage is about 622VDC.
However, it varies with the input power waveform.
⋅ The Pr. 883 setting should be kept higher than the DC bus voltage level. Otherwise, the regeneration avoidance function is always ON
even in the non-regeneration status and the frequency increases.
⋅ While overvoltage stall ( ) is activated only during deceleration and stops the decrease in output frequency, the regeneration
avoidance function is always ON (Pr. 882 = 1) or activated only during a constant speed (Pr. 882 = 2) and increases the
frequency according to the regeneration amount.
2
Pr.883
Time
Time
Regeneration avoidance operation
example for acceleration
Bus voltage
(VDC)
Output
frequency(Hz)
During regeneration
avoidance function operation
Pr.883
Time
Time
Regeneration avoidance operation
example for constant speed
Bus voltage
(VDC)
Output
frequency(Hz)
During regeneration
avoidance function operation
Pr.883
Time
Time
Bus voltage
(VDC)
Output
frequency(Hz)
During regeneration
avoidance function operation
Regeneration avoidance operation
example for deceleration
2