WEG SSW-06 - Page 157

CHAPTER 7 - PROGRAMMING INFORMATION AND SUGGESTIONS
157
Stopping (P104≠0 and P125=3):
1) Quadratic deceleration torque, 3 points=quadratic;
2) Applied to high water columns with high pressures;
3) Thiscontrolisusedwhenitisdi󰀩culttoachieveagradualpressure
drop without sudden pressure oscillations, mainly at the start of
the stopping process;
4) The best way to perform this is to use the load curve as a base
and set the 3 points 10% to 15% lower;
5) Set P128 initially to 50%;
6) Set P127 so that at the beginning of the pump stopping, the pressu-
re decreases gradually and no sudden pressure oscillation occurs;
7) Set P126 so that at the end of the pump stopping process the motor
is not still enabled for a long time.
Figure 7.21 - Hydraulic pump stopping with quadratic torque, 3 points
8) If the load shows a higher initial torque, use the quadratic torque
control (P120=3 points).
Figure 7.22 - Manometer showing the pressure drop, torque control
NOTES!
1) The main purpose of the torque control types applied to the stopping
is to maintain the drop in the pressure ramp as linear as possible,
decreasing the pressure gradually and thus preventing sudden
pressure oscillation, at the beginning, middle and at the end of
the stopping;
2) As already described in the pump control, the use of a measuring
instrument is required to measure the pressure and obtain the
best setting;
3) Remember: constant torque control is suitable for the greatest
number of applications and its use is very easy.
Tn(%)
Start
Speed
P128
0
Enable
Disable
t(s)
Maximum Time
P121
Tn Nominal
LoadTorque
Torque Control
P102
P122
P104
P126
P127
%Tn
0
P104
Tn Nominal
Speed
P127
P128
P126
t(s)
Disable
P401
P400
P640
P406
P404
P402
P405
P120 =2
P102
Controle
de Torque
P122
P121
P104 0
P125 =3
P126
P127
≠
P128