Mitsubishi Electric FR-A700 Instruction Manual page 530

Operation selection at power failure
Undervoltage avoidance function (Pr. 261 = 11 or 12, Pr. 294)
When Pr. 261 = "11, 12", the deceleration time is automatically adjusted (shortened) to prevent
undervoltage from occuring during deceleration at an instantaneous power failure.
Adjust the slope of frequency decrease and response level with Pr. 294. A larger setting will
improve responsiveness to the bus voltage.
Since the regeneration amount is large when the inertia is large, decrease the setting value.
NOTE Undervoltage avoidance function is invalid during torque control by real sensorless vector
control. When Pr. 261 = "11 (12)", the inverter operates in the same manner as when "1 (2)"
is set in Pr. 261.
Power failure deceleration signal (Y46)
After deceleration at an instantaneous power failure, inverter can not start even if the start com-
mand is given. In this case, check the power failure deceleration signal (Y46 signal). (at occur-
rence of input phase failure protection (E.ILF), etc.)
The Y46 signal is on during deceleration at an instantaneous power failure or during a stop after
deceleration at an instantaneous power failure.
For the Y46 signal, set "46 (source logic)" or "146 (sink logic)" in any of Pr. 190 to Pr. 196 (output
terminal function selection) to assign the function.
When Pr. 872 = 1 "Input phase failure protection provided" and Pr. 261 ≠ 0 (power failure
NOTES
stop function valid), input phase failure protection (E.ILF) is not provided but power-failure
deceleration is made.
When Pr. 30 "Regenerative function selection" = 2 (FR-HC, MT-HC, FR- CV is used), the
power failure deceleration function is invalid.
When the (output frequency − Pr. 262) at under voltage or power failure occurrence is nega-
tive, the calculation result is regarded as 0Hz. (DC injection brake operation is performed
without deceleration).
During a stop or error, the power failure stop selection is not performed.
Changing the terminal assignment using Pr. 190 to Pr. 196 "Output terminal function selec-
tion" may affect the other functions. Please make setting after confirming the function of
each terminal.
b
CAUTION:
If power-failure deceleration operation is set, some loads may cause the inverter to
trip and the motor to coast. The motor will coast if enough regenerative energy is given
from the motor.
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Parameter