Issue:
Minimum rating current for a motor to use with an ATS48 on a standard application.
Product Line:
ATS48
Environment:
Minimum current rating
Cause:
N/A
Resolution:
The performances are not affected, the goal is to protect the motor against thermal overloads.
The level of the thermal protection (ITH) is set with In parameter. The minimum for this parameter is 40%Icl so if you want to protect the motor with the internal thermal overload protection the nominal current of the motor must not be under 40% of Icl (starter max permanent current).
However it's possible to start a smaller motor (with external protection) the limit is fixed by the PHF fault current threshold. The minimum current controlled by the starter can be set to 5% of the nominal without SST function (see parameter PHL).
5% is the no load current (It's about 20% to 30% of the motor nominal current).
i.e for ATS48D17Q standard
Icl = 17A => 5%Icl = 0.85A
=> the nominal motor current mini must be about :
In min = (0.85/30)*100 = 2.8A