Mitsubishi Electric FR-E800 Instruction Manual page 265

• For example, the following calculation is used to find the setting value for Pr.8 when decreasing the output frequency from
the maximum frequency of 50 Hz in 10 seconds with Pr.20 = 120 Hz and Pr.10 = 3 Hz.
Pr.8 setting = 120 Hz × 10 s / (50 Hz - 3 Hz) ≈ 25.5 s
NOTE
• If the acceleration/deceleration time is set, the actual motor acceleration/deceleration time cannot be made shorter than the
shortest acceleration/deceleration time determined by the mechanical system J (moment of inertia) and motor torque.
• If the Pr.20 setting is changed, the settings of Pr.125 and Pr.126 (frequency setting signal gain frequency) do not change.
Set Pr.125 and Pr.126 to adjust the gains.
• Under PM sensorless vector control, if the protective function (E.OLT) is activated due to insufficient torque in the low-speed
range, set longer acceleration/deceleration times only in the low-speed range in Pr.791 Acceleration time in low-speed
range and Pr.792 Deceleration time in low-speed range.
 Changing the minimum increment of the acceleration/deceleration time
(Pr.21)
• Use Pr.21 to set the minimum increment of the acceleration/deceleration time.
Setting value "0" (initial value): minimum increment 0.1 s
Setting value "1": minimum increment 0.01 s
• Pr.21 setting allows the minimum increment of the following parameters to be changed.
Pr.7, Pr.8, Pr.16, Pr.44, Pr.45, Pr.791, Pr.792, Pr.1103
NOTE
• Pr.21 setting does not affect the minimum increment setting of Pr.611 Acceleration time at a restart.
• The operation panel provides a 4-digit readout (including the number of decimal places) on a value of parameters. Therefore,
a value of "100" or larger is set/displayed only in increments of 0.1 second even if Pr.21 = "1".
• When Pr.21 is set to "0" after the time is set in 0.01 s increments while Pr.21 is set to "1", the value is displayed in increments
of 0.1 second (rounded down to one decimal place). However, the value for the acceleration/deceleration time setting can be
set in increments of 0.01 second.
 Setting multiple acceleration/deceleration times (RT signal, Pr.44, Pr.45,
Pr.147)
• Pr.44 and Pr.45 are applied when the RT signal is ON or when the output frequency is equal to or higher than the
frequency set in Pr.147 Acceleration/deceleration time switching frequency.
• Even at the frequency lower than the Pr.147 setting, turning ON the RT signal switches the acceleration/deceleration time
to the second acceleration/deceleration time. The priority of the signals and settings is as follows: RT signal > Pr.147
setting.
• When "9999" is set in Pr.45, the deceleration time becomes equal to the acceleration time (time set in Pr.44).
• While the Pr.147 setting is equal to or less than the setting of Pr.10 DC injection brake operation frequency or Pr.13
Starting frequency, the time used as the acceleration/deceleration time switches to the time set in Pr.44 (Pr.45) when the
output frequency reaches or exceeds the Pr.10 or Pr.13 setting.
Pr.147 setting
9999 (initial value)
0.00 Hz
0.01 Hz ≤ Pr.147 ≤ Set frequency
Set frequency < Pr.147
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9. (F) Settings for Acceleration/Deceleration
9.1 Setting the acceleration and deceleration time
Acceleration/deceleration time
Pr.7, Pr.8
Pr.44, Pr.45
Output frequency < Pr.147: Pr.7, Pr.8
Pr.147 ≤ Output frequency: Pr.44, Pr.45
Pr.7, Pr.8
Description
Acceleration/deceleration time is not
automatically changed.
Second acceleration/deceleration time is
applied from the start.
Acceleration/deceleration time is
automatically changed.
Not changed as the frequency has not
reached the switchover frequency.