88
Setting of acceleration/deceleration time and acceleration/ deceleration pattern
(2) Deceleration time setting (Pr. 8, Pr. 20)
Use Pr. 8 Deceleration time to set the deceleration time required to reach 0r/min from Pr. 20 Acceleration/deceleration reference
speed.
Set the deceleration time according to the following formula.
(3) Set two kinds of acceleration/deceleration times (RT signal, Pr. 44, Pr. 45 )
Pr. 44 and Pr. 45 are valid when the RT signal is ON.
When "9999" is set to Pr. 45, the deceleration time becomes equal to the acceleration time (Pr. 44).
For the RT signal, set "3" in any of Pr. 178 to Pr. 182 (input terminal function selection) to assign the function.
(4) Setting the acceleration/deceleration time in the low-speed range (Pr. 791, Pr. 792)
If torque is required in the low-speed range (300r/min or less), set the Pr. 791 Acceleration time in low-speed range and Pr. 792
Deceleration time in low-speed range settings higher than the Pr. 7 Acceleration time and Pr.8 Deceleration time settings so that
the slow acceleration/deceleration is performed in the low-speed range.
The setting value of Pr. 785 PM control torque boost is the maximum generatable torque in the low-speed range (300r/min or
less). Refer to page 77
For the acceleration time, set the time takes to accelerate from a stop to Pr. 20 Acceleration/deceleration reference speed. For
the deceleration time, set the time takes to decelerate from Pr. 20 Acceleration/deceleration reference speed to a stop.
Deceleration
time setting
=
Pr. 20
× Deceleration time from maximum operating speed to stop
Maximum operating speed
Example) How to find the setting value for Pr. 8 when decreasing the rotation
speed from the maximum speed of 1800r/min in 10s with Pr. 20 =
3000r/min (initial setting).
Pr. 8 =
3000r/min
×
10s 16.7s
1800r/min
NOTE
When the acceleration/deceleration pattern is S-pattern acceleration/deceleration A (refer to page 90), the acceleration/
deceleration time is the time required to reach the rated motor speed.
Changing terminal assignment may affect the other functions. Set parameters after confirming the function of each
terminal.
REMARKS
⋅ The RT signal acts as the second function selection signal and makes the other second function valid. (Refer to page
103)
⋅ If the Pr. 20 setting is changed, the Pr. 125 and Pr. 126 (speed setting signal gain speed) settings do not change. Set Pr. 125
and Pr. 126 to adjust the gains.
⋅ Set Pr. 791 higher than Pr. 7, and Pr. 792 higher than Pr. 8. If set as Pr. 791 < Pr. 7, the operation is performed as Pr. 791 =
Pr. 7. If set as Pr. 792 < Pr. 8, the operation is performed as Pr. 792 = Pr. 8.
⋅ 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.
Parameters referred to
Pr. 29 Acceleration/deceleration pattern selection Refer to page 90
Pr. 125, Pr. 126 (speed setting gain speed) Refer to page 135
Pr. 178 to Pr. 182 (input terminal function selection)
Refer to page 100
Low-speed range
(300r/min or less)
(r/min)
Acceleration time
Slope set by Pr. 7
Deceleration time
Slope set by Pr. 8
Deceleration time
in low-speed range
Slope set by Pr. 792
cceleration time
in low-speed range
Slope set by Pr. 791
Time
Rotation speed
