Vacon Plc
Phone: +358-201 2121
Fax:+358-201 212 205
Service: +358-40-8371 150
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Page 32
Vacon
Pump and fan control with autochange
4. 1
Acc/Dec ramp 1 shape
4. 2
Acc/Dec ramp 2 shape
The start and end of the acceleration and deceleration ramps can be smoothed with
these parameters. Setting value 0 gives a linear ramp shape which causes
acceleration and deceleration to react immediately to the changes in the reference
signal with the time constant set by the parameter 1
.
3 and 1
.
4
(4
.
3 and 4
.
4).
Setting value 0.1—10 seconds for 4
.
1 (4
.
2) causes linear acceleration/deceleration
to adopt an S-shape. Parameters 1
.
3 and 1
.
4
(4
.
3 and 4
.
4) determine the time
constant of acceleration/deceleration in the middle of the curve.
See figure 6-13.
4. 3
Acceleration time 2
4. 4
Deceleration time 2
These values correspond to the time required for the output frequency to accelerate
from the set minimum frequency (par. 1
.
1) to the set maximum frequency
(par. 1
.
2). These times give the possibility to set two different acceleration/
deceleration time sets for one application. The active set can be selected with the
programmable signal DIA3 of this application, see parameter 2
.
2. Acceleration/
deceleration times can be reduced with an external free analogue input signal, see
parameters 2
.
18 and 2
.
19.
4. 5
Brake chopper
0 = No brake chopper
1 = Brake chopper and brake resistor installed
2 = External brake chopper
When the frequency converter is decelerating the motor, the inertia from the motor
and the load is fed into the external brake resistor. This enables the frequency
converter to decelerate the load with the torque equal to that of acceleration, if the
brake resistor is selected correctly. See separate Brake resistor installation manual.
[Hz]
[t]
4
.
1 (4
.
2)
4
.
1 (4
.
2)
UD009K20
1
.
3, 1
.
4
(4
.
3, 4
.
4)
Figure 6-13 S-shaped acceleration / deceleration.