CHAPTER 7 - APPLICATIONS AND PROGRAMMING
130
7.1.6.1 Loads with constant torque
(P202=3 and P120=1
point)
1) Set P121 as percent of the rated motor torque, necessary for the
motor + load during running process;
2) Set P102 to the time required for the motor start. Firstly program
short times: 10 to 15s;
3) With the torque control you can start the load smoothly within short
starting times due to the linearity of the start speed ramp.
Figure7.11
– Start with constant torque control - 1 point
7.1.6.2 Loads with initial high
torque (P202=3 and
P120=3 points)
1) Through this function you can achieve a smooth and linear starting
ramp. This function is very useful for driving belt conveyors;
2) Through the load curve you can set a starting torque 10% to 20%
higher than the load torque for each one of the points P121, P123,
P122 and the times at P102 and P124;
3) For the first start you can use a speed measuring instrument, thus
ensuring the desired acceleration or the desired speed curve;
4) If no load curves are available, you can apply a similar method as
the current ramp method. Also the torque limit, P120=1, can be
used for executing the first start-ups and afterward changing to this
function.
Figure 7.12
– Starting with quadratic torque control, 3 points,
with higher initial load
Tn(%)
Start
Speed
P102
0
Enable
Disable
t(s)
Maximum Time
P121
Tn Nominal
Load Torque
Torque Control
P120
=1
P102
Torque
Control
P401
P400
P104
=0
P121
P640
P406
P404
P402
P405
Tn(%)
Start
Speed
P124
0
Enable
Disable
t(s)
Maximum Time
P121
Tn Nominal
Load Torque
Torque Control
P123
P102
P122
P120
=3
P102
Torque
Control
P401
P400
P122
P121
P640
P406
P404
P402
P405
P123
P124
P104
=0
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