
Chapter 6 – Parameters
ACH 500 Programming Manual
6-21
Figure 6-5 Acceleration and Deceleration Ramp Shapes
3 ACCEL TIME 1
The time required for the output frequency to change from minimum to
maximum frequency. Regardless of the settings, the maximum acceleration/
deceleration is 120 Hz/0.1s and the minimum is120 Hz/1800s. The time
required for the acceleration from zero to minimum frequency depends on the
Accel Time (acceleration equals f
max
-f
min
/ acceleration time).
Note: The ACH 500 incorporates a bus controller that prevents overcurrent
and overvoltage trips caused by too quick acceleration and
deceleration settings for a given system (by increasing the
acceleration/deceleration).
If a small number is entered for acceleration time in a system with high
inertia, the acceleration time will be limited by Parameter 20.1.4 (Current
Limit). Conversely, if a small number is entered for deceleration time in such
a system, the deceleration time will be limited by the DC bus regulator. In
some cases, the motor will take a long time to come to a stop. If a short
deceleration time is critical to your application, we suggest you add a dynamic
braking device to your system.
The maximum/minimum recommended acceleration/deceleration for the
nominal size motor is 40 Hz in one second. If the motor rating is less than the
maximum power of the ACH 500, smaller settings can be used.
If the reference signal changes at a rate slower than the acceleration or
deceleration time, the output frequency change will follow the reference
signal. If the reference signal changes faster than the acceleration or
deceleration time, the output frequency change will be limited by the
parameters.
4 DECEL TIME 1
The time required for output frequency to change from maximum to
minimum. Refer to Parameter 20.3.3.
5 ACCEL TIME 2
Refer to Parameter 20.3.3.
S2
S3
Linear
S1
60
[Hz]
1
t [s]
f
out
1.25
2