211
Special operation and speed control
4
PARAMETERS
4.17.2 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 speed 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 speed to avoid the regenerative status.
Possible to avoid regeneration by automatically increasing the speed 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
400VDC 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
×
"
∗
.
885
Regeneration
avoidance
compensation speed
limit value
180r/min
0 to 900r/min/
0 to 600r/min ∗
Limit value of speed which rises at activation of regeneration
avoidance function.
9999 Speed 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 rotation speed could become unstable.
When vibration is not suppressed by decreasing the Pr. 886
setting, set a smaller value in Pr. 665.
665
Regeneration
avoidance speed gain
100% 0 to 200%
The above parameters can be set when Pr. 160 Extended function display selection = "0". (Refer to page 144)
∗ Differs according to capacities. (0.2K to 2.2K/3.7K)
2
Bus voltage
(VDC)
Regeneration avoidance operation example
for acceleration
Pr. 883
Rotation speed
(r/min)
During regeneration
avoidance function operation
Time
Time
Bus voltage
(VDC)
Regeneration avoidance operation example
for constant speed
Pr. 883
Rotation speed
(r/min)
During regeneration avoidance
function operation
Time
Time
Bus voltage
(VDC)
Regeneration avoidance
operation example for deceleration
Pr. 883
Rotation speed
(r/min)
Time
Time
During regeneration
avoidance function operation
