CD Automation srl
STE Soft Starter
User’s Manual
36
7.2.7
Thermal Overload
The starter continuosly calculated the temperature rise of the motor based on the controlled nominal
current In and the actual current absorbed. Temperature rises can be caused by a low or high overload
with a long or short duration.The tripping curves are based on the relationship between the starting
current I and the (adjustable) motor current In.
Standard IEC 60947-4-2 defines the protection classes giving the starting capacities of the motor
without thermal faults. Different protection classes are given for a thermal state at nominal power.
The thermal state is calculated only with the control circuit powered.The starter thermal control prevents
the motor from restarting if the temperature rise is too high.
7.2.8
Unbalanced
This critical alarm is active when one of the three motor current (read on the terminals M1, M2, M3)
differs from the others more than the threshold value set in the parameter P040
0C'
for a time set in
the parameter P041
0C/
(see par. 9).
The unbalanced alarm could be active also if there are a wrong wiring of the motor winding.
When the problem is solved before to restart is necessary Reset the Alarm (see par. 6.5)
7.2.9
Start Failure
This critical alarm is active when the output voltage not reaches the nominal value in the maximum start
time (30sec.).
For restart the STE Soft Starter, check the motor mechanism or increase the Initial Voltage.
When the problem is solved before to restart is necessary Reset the Alarm (see par. 6.5)
Summary of Contents for STE Series
Page 1: ...USER S MANUAL Rev 01 2007 STE Enhanced Soft Starter ...
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