Mitsubishi FR-A800

(G) Control parameters
PARAMETERS
621
5
GROUP
G
5.16.11 Regeneration avoidance function
What is regeneration avoidance operation? (Pr.882, Pr.883)
• When the regenerative status is large, DC bus voltage will rise, which may cause overvoltage alarm (E.OV[]).
Regenerative status can be avoided by detecting this rise of bus voltage, and raising the frequency when the bus voltage
level exceeds Pr.883 Regeneration avoidance operation level.
• The regeneration avoidance operation can be selected to operate constantly or operate only during constant speed.
• The regeneration avoidance function is enabled by setting to Pr.882 Regeneration avoidance operation selection = "1,
2".
The regenerative status can be avoided by detecting the regenerative status and raising the frequency.
• Continuous operation is possible by increasing the frequency automatically so it will not go into regenerative
operation even when the fan is turned forcefully by other fans in the same duct.
Pr. Name Initial value
Setting
range
Description
882
G120
Regeneration avoidance
operation selection
0
0 Disables regeneration avoidance function
1 Constantly enables regeneration avoidance function
2
Enables regeneration avoidance function only during
constant-speed operation
883
G121
Regeneration avoidance
operation level
200 V
Class
380 VDC
300 to 800 V
Set the bus voltage level to operate the regeneration
avoidance operation. When the bus voltage level is set
low, it will be harder to generate overvoltage error, but
actual deceleration time will be longer.
Set the setting value higher than power supply voltage
 .
400 V
Class
760 VDC
884
G122
Regeneration avoidance
at deceleration detection
sensitivity
0
0
Disables regeneration avoidance due to bus voltage
change rate
1 to 5
Set the sensitivity to detect the bus voltage change rate
Setting value 1 5
Detection sensitivity Low High
885
G123
Regeneration avoidance
compensation frequency
limit value
6 Hz
0 to 590 Hz
Set the limit value for frequency to rise when the
regeneration avoidance function operates.
9999 Disables frequency limit
886
G124
Regeneration avoidance
voltage gain
100% 0 to 200%
Adjust the response at the time of regeneration
avoidance operation. When the setting value is set
larger, response against the bus voltage change will
improve, but the output frequency may become
unstable.
When the vibration cannot be stabilized even if the
setting value of Pr.886 is made smaller, set the setting
value of Pr.665 smaller.
665
G125
Regeneration avoidance
frequency gain
100% 0 to 200%
•
•
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