Mitsubishi Electric FR-A720-0.4K Instruction Manual page 268

Operation selection at power failure
and instantaneous power failure
(4) 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.
1.5K or less . . . . . . 0.5s, 2.2K to 7.5K. . . . . . 1s, 11K to 55K . . . . . . . . . 3.0s, 75K 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.
(5) 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 magnitude 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 control or vector control.
Voltage
100%
Pr.164
(Pr.163)
CAUTION
⋅
Changing the terminal assignment using Pr. 178 to Pr. 189 (input terminal function selection) may affect the other functions. Please
make setting after confirming the function of each terminal.
⋅
When automatic restart operation is selected, undervotage protection (E.UVT) and instantaneous power failure protection
(E.IPF) among the alarm output signals will not be provided at occurrence of an instantaneous power failure.
⋅
The SU and FU signals are not output during a restart. They are output after the restart cushion time has elapsed.
⋅
Automatic restart operation will also be performed after a reset made by an inverter reset is canceled or when a retry is made
by the retry function.
⋅
Automatic restart after instantaneous power failure function is invalid when load torque high speed frequency control (Pr. 270 =
"2, 3") is set.
Provide mechanical interlocks for MC1 and MC2. The inverter will be damaged if the power supply is input to the
inverter output section.
When automatic restart after instantaneous power failure has been selected, the motor and machine will start
suddenly (after the reset time has elapsed) after occurrence of an instantaneous power failure. Stay away from
the motor and machine. When you have selected automatic restart after instantaneous power failure function,
apply in easily visible places the CAUTION stickers supplied to the instruction manual (basic).
♦ Parameters referred to ♦
Pr. 7 Acceleration time, Pr. 21 Acceleration/deceleration time increments
Pr. 13 Starting frequency Refer to page 170
Pr. 65, Pr. 67 to Pr. 69 Retry function
Pr. 78 Reverse rotation prevention selection
Pr. 178 to Pr. 189 (input terminal function selection)
258
(6) Automatic restart operation adjustment (Pr. 163 to
Pr.58
Time
CAUTION
Refer to page 262
Refer to page 296
Refer to page 222
Pr. 165, Pr. 611)
⋅ Using Pr. 163 and Pr. 164, you can adjust the voltage rise time at a
restart as shown on the left.
⋅ 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 automatic restart operation is performed
besides the normal acceleration time.
REMARKS
⋅ If the setting of Pr. 21 Acceleration/deceleration time increments is
changed, the setting increments of Pr. 611 does not change.
Refer to page 168