Mitsubishi Electric FR-A820-00046 Instruction Manual page 437

Parameters
Optimum acceleration/deceleration (Pr. 292 = "3", Pr. 293)
● The inverter operates at the most efficient level within the rated range that can be used continu-
ously with reasonable inverter capacity.
Using self-learning, the average current during acceleration/deceleration is automatically set so
as to become the rated current.
This is ideal for applications operated with a predetermined pattern and minimal load fluctua-
tions, such as by an automatically operated conveyor.
● When the optimum acceleration/deceleration is selected, at first, the operation is performed with
the values set in Pr. 0 "Torque boost", Pr. 7 "Acceleration time", and Pr. 8 "Deceleration time". After
the first operation is completed, average and peak currents are calculated based on the motor
current during acceleration/deceleration, and the obtained values are compared with the refer-
ence current (initially set to the rated inverter current) to adjust the Pr. 0, Pr. 7, and Pr. 8 settings
to their optimal values.
The operation is the performed with the updated Pr. 0, Pr. 7, and Pr. 8 values onwards, and those
parameters settings are adjusted each time.
Under Advanced magnetic flux vector control, Real sensorless vector control and vector control,
however, the Pr. 0 setting is not changed.
● When a Regenerative overvoltage trip during deceleration or stop (E.OV3) occurs during deceler-
ation, the setting of Pr. 8 is multiplied by 1.4.
● Parameter storage
The optimum values of Pr. 0, Pr. 7 and Pr. 8 are written to both the parameter RAM and EEPROM
only three times of acceleration (deceleration) after the optimum acceleration/deceleration has
been selected or after the power is switched ON or the inverter is reset. At or after the fourth
attempt, they are not stored into EEPROM. Hence, after power-ON or inverter reset, the values
changed at the third time are valid. However, the optimum values are calculated even for the
fourth time and later, and Pr. 0, Pr. 7, and Pr. 8 are set to the RAM; therefore, these can be stored
to the EEPROM by reading and writing the settings with the operation panel (FR-DU08).
Number of optimum value
changes
1 to 3 times
4 and more times
Tab. 5-97:
● Either acceleration or deceleration can be made in the optimum acceleration/deceleration using
Pr. 293 "Acceleration/deceleration separate selection". When the setting value is "0" (initial value),
both acceleration and deceleration are made in the optimum acceleration/deceleration.
● It is inappropriate for machines which change in load and operation conditions.
Optimum values are saved for the next operation. If the operating condition changes before the
next operation, a fault such as overcurrent trip or a lack of acceleration/deceleration may occur.
FR-A800
(F) Setting of acceleration/deceleration time and acceleration/deceleration pattern
EEPROM value
Updated
Unchanged from the 3rd value
Storage of optimum values
Pr. 0, Pr. 7, Pr. 8
RAM value
Updated
Updated
Operating condition
Updated
Updated
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