WEG SSW-07 - Voltage Ramp Starting

CHAPTER 5 - PROGRAMMING INFORMATION AND SUGGESTIONS
37
English
5.1.1 Voltage Ramp
Starting
Current
Torque
T/Tn
Tn
I/In
Figure 5.2 - Characteristic curves of torque and current in a
current limitation start
1) Set the value of the initial voltage to a low value;
2) When a load is applied to the motor, set the initial voltage to a
value that makes the motor rotate smoothly from the instant it is
started.
3) Set the acceleration time with the necessary start time, initially
withshorttimes,10to15seconds,andafterwardstrytondthe
best starting condition for the used load.
100%Un
Start
U(V)
Disable
Voltage Ramp
Enable
t(s)
0
Figure 5.3 - Voltage ramp starting
NOTES!
 With long starting times, or when the motor is without a load,
vibration can occur during the start of the motor, therefore lower
the starting time;
 If faults occur during the start, check all the connections from the
Soft-Starter to the supply network, motor connections, supply
network voltage levels, fuses and circuit breakers.