Regeneration Avoidance Function (Pr. 882 To Pr. 886) - Mitsubishi Electric FR-F740-00023 Instruction Manual

Special operation and frequency control

4.20.5 Regeneration avoidance function (Pr. 882 to Pr. 886)

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
Name
Number
Regeneration
882 avoidance operation
selection
Regeneration
883 avoidance operation
level
Regeneration
avoidance at
884
deceleration
detection sensitivity
Regeneration
avoidance
885
compensation
frequency limit value
Regeneration
886 avoidance voltage
gain
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 173)
(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.
Regeneration avoidance operation
example for acceleration
Pr.883
During regeneration
avoidance function operation
Setting Pr. 882 to "1, 2" validates the regeneration avoidance function.
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
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-regeneraion status and the frequency increases.
While overvoltage stall (
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.
Note that when coping parameters to the inverter without this function (inverter assembled in and before September 2005),
copied Pr.882 ="2" is regarded as Pr.882 ="0"(regeneration avoidance function invalid).
248
Initial Setting
Value Range
0
1
0
2
760VDC/
300 to 800V
785VDC *
0
0
1 to 5
0 to 10Hz
6Hz
9999
100% 0 to 200%
Regeneration avoidance operation
example for constant speed
Pr.883
Time
During regeneration
avoidance function operation
Time
2
) is activated only during deceleration and stops the decrease in output frequency, the regeneration
Regeneration avoidance function invalid
Regeneration avoidance function valid
Regeneration avoidance function is valid only during a constant
speed operation
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 .
2
* The initial value differs according to the inverter capacity.
(01160 or less/01800 or more)
Regeneration avoidance by bus voltage change ratio is invalid
Set sensitivity to detect the bus voltage change ratio
Setting
Detection sensitivity low
Set the limit value of frequency which rises at activation of
regeneration avoidance function.
Frequency limit invalid
Adjusts responsiveness at activation of regeneration avoidance.
A larger setting will improve responsiveness to the bus voltage
change. However, the output frequency could become unstable.
Time
Time
times greater than the input voltage.
Description
1 5
high
Regeneration avoidance operation
example for deceleration
Pr.883
During regeneration
avoidance function operation
Time
Time