Mitsubishi Electric 800 Series Instruction Manual (Function page 490

17.9
Regeneration avoidance function
The regenerative status can be detected and avoided by raising the frequency.
• The operation frequency is automatically increased to prevent the regenerative operations. This function is useful when a
load is forcibly rotated by another fan in the duct.
Pr. Name
Regeneration
882
avoidance operation
G120
selection
Regeneration
883
avoidance operation
G121
level
Regeneration
885 avoidance
G123 compensation
frequency limit value
886 Regeneration
G124 avoidance voltage gain
Regeneration
665
avoidance frequency
G125
gain
 Regeneration avoidance operation (Pr.882, Pr.883)
• When the regenerative voltage increases, the DC bus voltage will rise, which may cause an overvoltage fault (E.OV[]). The
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 "1 or 2" in Pr.882 Regeneration avoidance operation
selection.
Regeneration avoidance operation
example for acceleration
Pr. 883
During regeneration
avoidance function operation
Setting
Initial value
range
0
1
0
2
200 V
400 VDC
class
400 V
780 VDC
300 to 1200 V
class
575 V
944 VDC
class
0 to 45 Hz
6 Hz
9999
100% 0% to 200%
100% 0% to 200%
Regeneration avoidance operation
example for constant speed
Pr. 883
Time
During regeneration
avoidance function operation
Time
Description
The regeneration avoidance function is disabled.
The regeneration avoidance function is always enabled.
The regeneration avoidance function is enabled only during
constant-speed operation.
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 the (power supply voltage ×
√
) value.
2
Set the limit value for frequency to rise when the regeneration
avoidance function is activated.
The frequency limit is disabled.
Adjust the response during the regeneration avoidance
operation. Increasing the setting improves the response to
change in the bus voltage. However, the output frequency may
become unstable. If setting a smaller value in Pr.886 does not
suppress the vibration, set a smaller value in Pr.665.
Regeneration avoidance operation
example for deceleration
Pr. 883
Time
During regeneration
avoidance function operation
Time
17.9 Regeneration avoidance function
Time
Time
489
17. (G) Control Parameters
11
12
13
14
15
16
17
18
19
20