Xylem SSW-07 Soft-Starter - Manual (Page 40)

CHAPTER 5 - PROGRAMMING INFORMATION AND SUGGESTIONS
39
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 find 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.