Mitsubishi Electric 800 Series Instruction Manual page 617

(G) Control parameters
Adjustment of regeneration avoidance operation (Pr.665, Pr.886)
• When the frequency becomes unstable at the time of regeneration avoidance operation, set the setting value for Pr.886
Regeneration avoidance voltage gain smaller. On the other hand, if an overvoltage fault occurs due to a sudden
regeneration, increase the setting.
• When the vibration cannot be stabilized even if the setting value of Pr.886 is made smaller, set the setting value of Pr.665
Regeneration avoidance frequency gain smaller.
NOTE
• During the regeneration avoidance operation, the stall prevention (overvoltage) (oL) is displayed and the overload alarm (OL)
signal is output. The operation when the OL signal is output can be set with Pr.156 Stall prevention operation selection.
The OL signal output timing can be set with Pr.157 OL signal output timer.
• The stall prevention is enabled even at the time of regeneration avoidance operation.
• The regeneration avoidance function cannot decrease the actual deceleration time for the motor to stop. The actual
deceleration time is determined by the regenerative power consumption performance, so to decrease the deceleration time,
consider using a regeneration unit (brake unit) or a brake resistor.
• When using a regeneration unit (brake unit) or a brake resistor to consume the regenerative power, set to Pr.882 = "0 (initial
value)" (disables regeneration avoidance function). When consuming the regenerative power at the time of deceleration with
the regeneration unit, etc., set to Pr.882 = "2" (enables regeneration avoidance function only at the time of constant speed).
• When using the vector control and the regeneration avoidance function together, there may be a sound from the motor at the
time of deceleration. In such case, adjust the gain by performing easy gain tuning, etc. (Refer to
Parameters referred to
Pr.1 Maximum frequency
Pr.8 Deceleration time page 269
Pr.22 Stall prevention operation level
616
PARAMETERS
page 329
page 332
page 164.)