Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual page 602

NOTE
• The rotation speed detection time (frequency search) changes according to the rotation speed of the motor. (maximum 1 s)
• When the inverter capacity is two ranks or greater than the motor capacity, the overcurrent protective function (E.OC[]) is
sometimes activated and prevents the inverter from restarting.
• If two or more motors are connected to one inverter, this function operates abnormally. (The inverter does not restart
successfully.)
• Because a DC injection brake is applied instantaneously at speed detection during a restart, the speed might drop if the
moment of inertia (J) of the load is small.
• If reverse operation is detected when "1" (reverse rotation disabled) is set to Pr.78, operation decelerates by reverse rotation
and then changes to forward rotation when the start command is forward rotation. The inverter does not restart when the start
command is reverse rotation.
• When "3 or 13" is set to Pr.162, limit the wiring length to within 100 m.
 Restart operation without frequency search (Pr.162 = "1 or 11")
• When Pr.162 = "1 or 11", reduced voltage start is used for the restart operation. In this method, the voltage is raised
gradually while keeping the output frequency level at the level before an instantaneous power failure, regardless of the
motor's coasting speed.
V/F control, Advanced magnetic flux vector control
Instantaneous (power failure) time
Power supply
(R/L1, S/L2,
T/L3)
Motor speed N
(r/min)
Inverter output
*
frequency f(Hz)
Inverter output
voltage E(V)
Coasting time
Pr.57 setting
* The output shut off timing differs according to the load condition.
NOTE
• This restart method uses the output frequency that was active before the instantaneous power failure stored in memory. If the
instantaneous power failure time is 0.2 s or more, the output frequency can no longer be stored and held in memory, so the
restart is performed from Pr.13 Starting frequency (initial value: 0.5 Hz).
• During Real sensorless vector control, Pr.162 is set to "3 or 13" (reduced impact restart).
 Restart operation with encoder detection frequency search (Pr.162 = "2
or 12")
• When "2 or 12" is set in Pr.162 by encoder feedback control, the inverter is restarted by the motor speed and direction of
rotation that were detected by the encoder at the power restoration.
Restart cushion time
(Pr.58 setting)
5. PARAMETERS
5.14 (A) Application parameters
1
2
3
4
5
6
7
8
9
10
601