Mitsubishi Electric FR-A800 Series Instruction Manual page 374

 Linear acceleration/deceleration (Pr.29 = "0 (initial value)")
• When the frequency is changed for acceleration, deceleration, etc. during inverter operation, the output frequency is
changed linearly (linear acceleration/deceleration) to reach the set frequency without straining the motor and inverter.
Linear acceleration/deceleration has a uniform frequency/time slope.
Setting value "0"
[Linear acceleration
/ deceleration]
 S-pattern acceleration/deceleration A (Pr.29 = "1")
• Use this when acceleration/deceleration is required for a short time until a high-speed area equal to or higher than the base
frequency, such as for the main shaft of the machine.
• The acceleration/deceleration pattern has the Pr.3 Base frequency (Pr.84 Rated motor frequency under PM motor
control) (fb) as the point of inflection in an S-pattern curve, and the acceleration/deceleration time can be set to be suitable
for the motor torque reduction in the constant-power operation range at the base frequency (fb) or more.
[S-pattern acceleration
/deceleration A]
fb
• Acceleration/deceleration time calculation method when the set frequency is equal to or higher than the base frequency
Acceleration time t = (4/9) × (T/fb
Where T is the acceleration/deceleration time (s), f is the set frequency (Hz), and fb is the base frequency (rated motor
frequency)
• Reference (0 Hz to set frequency) of acceleration/deceleration time when Pr.3 = 60 Hz
Acceleration/deceleration
time (s)
5
15
NOTE
• For the acceleration/deceleration time setting of the S-pattern acceleration/deceleration A, set the time to Pr.3 (Pr.84 under
PM sensorless vector control) instead of Pr.20 Acceleration/deceleration reference frequency.
 S-pattern acceleration/deceleration B (Pr.29 = "2")
• This is useful for preventing collapsing stacks such as on a conveyor. S-pattern acceleration/deceleration B can reduce
the impact during acceleration/deceleration by accelerating/decelerating while maintaining an S-pattern from the present
frequency (f2) to the target frequency (f1).
[S-pattern acceleration
/deceleration B]
f1
f2
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Time
Time
2 2
) × f + (5/9) × T
Set frequency (Hz)
60 120
5 12
15 35
Time
search engine
200 400
27 102
82 305
5.8 (F) Setting of acceleration/deceleration time and acceleration/deceleration pattern
1
2
3
4
5
6
7
8
9
10
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5. PARAMETERS