CHAPTER 7 - PROGRAMMING INFORMATION AND SUGGESTIONS
148
7.1.4 Starting by Current Ramp
with Low Initial Current
(P202=4)
1) To start the motor with current ramp you must apply load on the
motor. No-load tests can be done by voltage ramp;
2) Use this function to help starting loads that require a lower initial
torque, as fans and blowers;
3) When such a load is started with fixed current limit, you can note
that the motor starts accelerating and than stops to accelerate;
4) As solution we recommend setting a lower initial current to only
starting rotating and than increase the current limit gradually until
the end of the start. In this way you will certainly ensure a smooth
start;
5) Set P111 to the current value required to start rotating the motor
only;
6) Set P112 initially to 75% of P102(20s) = 15s and then increase
it gradually;
7) The motor must start rotating as soon as it is enabled;
8) Set P110 with current limit that maintains the motor accelerating;
9) The motor must accelerate till the start end.
Figure 7.6
- Starting with current ramp, initial lower current
NOTES!
1) If the current limit is not reached during the starting, the motor will
reach nominal speed immediately;
2) P401 must be set according to the current of the used motor;
3) A low Current Limit results in too low torque for the motor start.
Always maintain the motor running after it has been enabled;
4) If errors are detected during the motor start, check all connections
of the Soft-Starter to the power line, the motor connections, the
voltage levels of the power line, the fuses, circuit-breakers and
disconnecting switches.
I(A)
Start
I Nominal
P110
P102
0
Enable
Current Ramp
Disable
t(s)
I Limit
Maximum Time
P111
P112
P110
P102
Current
Ramp
P401
P400
P112
P111
P640
P406
Summary of Contents for SSW06
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