Mitsubishi Electric FR-A700 Instruction Manual page 524

Operation selection at power failure
Restart coasting time (Pr. 57)
Coasting time is the time from when the motor speed is detected until automatic restart control
is started.
Set Pr. 57 to "0" to perform automatic restart operation. The coasting time is automatically set
to the value below. Generally this setting will pose no problems.
00052 or less . . . . 0.5s, 00083 to 00250 . . . 1s, 00310 to 01800 . . . . . 3.0s, 02160 or more . . . 5.0s
Operation may not be performed well depending on the magnitude of the moment (J) of inertia
of the load or running frequency. Adjust the coasting time between 0.1s and 5s according to the
load specifications.
Restart cushion time (Pr. 58)
Cushion time is the length of time taken to raise the voltage appropriate to the detected motor
speed (output frequency prior to instantaneous power failure when Pr. 162 = "1" or "11").
Normally the initial value need not be changed for operation, but adjust it according to the mag-
nitude of the moment (J) of inertia of the load or torque.
Pr. 58 is invalid during encoder feedback control (Pr. 162 = "2, 12"), real sensorless vector con-
trol or vector control.
Automatic restart operation adjustment (Pr. 163 to Pr. 165, Pr. 611)
Using Pr. 163 and Pr. 164, you can adjust the voltage rise time at a restart as shown below.
Using Pr. 165, you can set the stall prevention operation level at a restart.
Using Pr. 611, you can set the acceleration time until the set frequency is reached after auto-
matic restart operation is performed besides the normal acceleration time.
NOTE
If the setting of Pr. 21 "Acceleration/deceleration time increments" is changed, the setting
increments of Pr. 611 does not change.
6 - 344
Voltage
Fig. 6-162:
Voltage rise at automatic restart
Time
Parameter
I001170E