Mitsubishi Electric FR-F800 Series Instruction Manual page 575

• Set the frequency around the motor rated slip frequency. Increase the setting value if the overvoltage protection function
(E.OV[]) is activated at the start of deceleration.
Rated motor slip frequency =
 Adjusting the regeneration avoidance operation (Pr.665, Pr.886)
• If the frequency becomes unstable during regeneration avoidance operation, decrease the setting of Pr.886 Regeneration
avoidance voltage gain. On the other hand, if an overvoltage fault occurs due to a sudden regeneration, increase the
setting.
• If setting a smaller value in Pr.886 does not suppress the vibration, set a smaller value in Pr.665 Regeneration avoidance
frequency gain.
NOTE
• During the regeneration avoidance operation, the stall prevention (overvoltage) "oL" is displayed and the Overload warning
(OL) signal is output. Set the operation pattern at an OL signal output using Pr.156 Stall prevention operation selection.
Use Pr.157 OL signal output timer to set the OL signal output timing.
• The stall prevention is enabled even during regeneration avoidance operation.
• The regeneration avoidance function cannot decrease the actual deceleration time for the motor to stop. Since the actual
deceleration time is determined by the regenerative power consumption performance, consider using a regeneration unit (FR-
BU2, BU, FR-BU, FR-CV, FR-HC2, or FR-XC) to decrease the deceleration time.
• When using a regeneration unit (FR-BU2, BU, FR-BU, FR-CV, FR-HC2, or FR-XC) to consume the regenerative power at
constant speed, set Pr.882 = "0 (initial value)" to disable the regeneration avoidance function. When consuming the
regenerative power at the time of deceleration with the regeneration unit, etc., set Pr.882 = "2" (enables regeneration
avoidance function only at the constant speed).
Parameters referred to
Pr.1 Maximum frequencypage 287
Pr.8 Deceleration timepage 228
Pr.22 Stall prevention operation
5.13.13 Increased magnetic excitation deceleration
Magnetic flux Magnetic flux Magnetic flux
V/F V/F V/F
Increase the loss in the motor by increasing the magnetic flux during deceleration. The deceleration time can be reduced by
suppressing the stall prevention (overvoltage) (oL).
The deceleration time can further be shortened without a brake resistor.
Pr.
Increased magnetic
660
excitation deceleration
G130
operation selection
661 Magnetic excitation
G131 increase rate
662 Increased magnetic
G132 excitation current level
 Setting of increased magnetic excitation rate (Pr.660, Pr.661)
• To enable the increased magnetic excitation deceleration, set Pr.660 Increased magnetic excitation deceleration
operation selection = "1".
• Set the amount of excitation increase in Pr.661 Magnetic excitation increase rate.
574
5. PARAMETERS
5.13 (G) Control parameters
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Synchronized speed at the time of base frequency – rated rotation speed
Synchronized speed at the time of base frequency
Limit level
Output frequency (Hz)
Pr.885
Pr.885/2
Time
levelpage 290
Name Initial value
0
9999
100%
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Setting
range
0 Without the increased magnetic excitation deceleration function
1 With the increased magnetic excitation deceleration function
0% to 40% Set the increase of excitation.
9999 and Advanced magnetic flux vector control.
The increased magnetic excitation rate is automatically lowered
0% to 300% when the output current exceeds the setting value during increased
magnetic excitation deceleration.
× Rated motor frequency
Description