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Special operation and frequency control
4.20.3 Regeneration avoidance function (Pr. 665, Pr. 882, Pr. 883, Pr. 885, Pr. 886)
(1) What is regeneration avoidance function? (Pr. 882, Pr. 883)
When the regeneration load is large, 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 function is always on when "1" is set in Pr. 882, and activated only during a constant speed
when "2" is set in Pr. 882.
This function detects a regeneration status and increases the frequency to avoid the regenerative status.
Possible to avoid regeneration by automatically increasing the frequency to 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 is always valid
2
Regeneration avoidance function is valid only during a constant
speed operation
883
Regeneration
avoidance operation
level
200V
class
400
VDC
300 to 800V
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
780
VDC
885
Regeneration
avoidance
compensation
frequency limit value
6Hz
0 to 10Hz
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%
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 Extended function display selection = "0". (Refer to page 162)
2
Bus voltage
(VDC)
Regeneration avoidance operation example
for acceleration
Pr. 883
Output
frequency
(Hz)
During regeneration
avoidance function operation
Time
Time
Bus voltage
(VDC)
Regeneration avoidance operation example
for constant speed
Pr. 883
Output
frequency
(Hz)
During regeneration avoidance
function operation
Time
Time
Bus voltage
(VDC)
Regeneration avoidance
operation example for deceleration
Pr. 883
Output
frequency
(Hz)
Time
Time
During regeneration
avoidance function operation