Mitsubishi Electric FR-F740 EC User Manual

Special operation Parameter
6 - 386
6.20.3 Regeneration avoidance function (Pr. 665, Pr. 882 to Pr. 886)
This function detects a regeneration status and increases the frequency to avoid the regener-
ation status.
Possible to avoid regeneration by automatically increasing the frequency and continue opera-
tion if the fan happens to rotate faster than the set speed due to the effect of another fan in the
same duct.
The above parameters can be set when Pr. 160 = 0.
What is regeneration avoidance function? (Pr. 882, Pr. 883)
When the regeneration status is serious, the DC bus voltage rises and an over voltage alarm
(E.OV첸) 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 performed during any of acceleration, constant speed
and deceleration.
Pr. No. Name
Initial
Value
Setting
Range
Description Parameters referred to
Refer to
Section
882
Regeneration
avoidance operation
selection
0
0 Regeneration avoidance function invalid
1
8
22
Maximum
frequency
Deceleration time
Stall prevention
operation level
6.3.1
6.6.1
6.2.4
1 Regeneration avoidance function valid
883
Regeneration
avoidance operation
level
760V DC/
785V DC *
300–800V
Set the bus voltage level at which regener-
ation avoidance operates. When the bus
voltage level is set to low, over voltage
error will be less apt to occur. However, the
actual deceleration time increases. The set
value must be higher than the power sup-
ply voltage x √2
.
* The initial value differs according to the
inverter capacity.
(01160 or less/0180 or more)
884
Regeneration
avoidance at
deceleration detection
sensitivity
0
0
Regeneration avoidance by bus voltage
change ratio is invalid
1–5
Set sensitivity to detect the bus voltage
change
1 (low) → 5 (high)
885
Regeneration
avoidance
compensation
frequency limit value
6Hz
0–30Hz
Set the limit value of frequency which rises
at activation of regeneration avoidance
function.
9999 Frequency limit invalid
886
Regeneration
avoidance voltage
gain
100% 0–200%
Adjust responsiveness at activation of
regeneration avoidance.
A larger setting of Pr. 886 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% 0–200%
I001257E
Fig. 6-214: Regeneration avoidance function
Bus voltage
[V DC]
Output
frequency [Hz]
Regeneration avoidance operation
example for acceleration
Regeneration avoidance operation
example for constant speed
Regeneration avoidance operation
example for deceleration
Pr. 883
Pr. 883
Pr. 883
During regeneration avoidance
function operation
During regeneration avoidance
function operation
Time
Time
Time
Bus voltage
[V DC]
Output
frequency [Hz]
Bus voltage
[V DC]
Output
frequency [Hz]
During regeneration avoidance
function operation

Mitsubishi Electric FR-F740 EC Specifications

General

Brand	Mitsubishi Electric
Model	FR-F740 EC
Category	Inverter
Language	English