Mitsubishi Electric FR-A820-00046 Instruction Manual page 764

(A) Application parameters
Continuous operation function at instantaneous power failure (Pr. 261 = "2, 12, 22")
● The motor re-accelerates to the set frequency if the power restores during the deceleration to stop.
● Combining with the automatic restart after instantaneous power failure function enables a power
failure time deceleration stop and re-acceleration at a power restoration.
If the power is restored after stoppage by a power failure, a restart operation is performed when
automatic restart after instantaneous power failure (Pr. 57 ≠ "9999") is selected.
Pr. 261 = 2
Power
supply
Output
frequency
Y46
Fig. 5-293:
Undervoltage avoidance function (Pr. 261 = "11, 12", Pr. 294)
● If "11, 12" is set to Pr. 261, the deceleration time is adjusted (shortened) to prevent an undervoltage
from occurring during deceleration at occurrence of power failure.
● Adjust the downward frequency slope and the response level using Pr. 294 "UV avoidance voltage
gain". Setting a large value improves the response to the bus voltage.
NOTE The undervoltage avoidance function is invalid under torque control by Real sensorless vector
control. When "11 (12)" is set to Pr. 261, operation is the same as when "1 (2) is set to Pr. 261.
5 - 584
When power is restored during
deceleration at occurrence of power failure
IPF
During deceleration
at occurrence of
Reacceleration *
power failure
* Acceleration time depends on Pr. 7 (Pr. 44 ).
Operation continuation at instantaneous power failure
≠
Pr. 261 = 2, Pr. 57 9999
Power
supply
Output
frequency
During deceleration
at occurrence of
power failure
Time
Y46
Parameters
When used with automatic restart
after instantaneous power failure
During power failure
Automatic restart
after instantaneous
power failure
Time
I002720E