Short circuit fault (SCF) on Alit start 22

Anonymous user · ‎2021-09-30

Replaced an old, but working telemecanique soft starter with a new AYS22D75Q for a 30kw cement mixer wired in Delta.

When I start the motor it runs for a moment then faults out on SCF... strange this is when I change the DLTA parameter back to LINE the motor seems to run fine under no load.

I'll be going back tomorrow morning to run under load but I'm expecting some high Amps and higher temps. I have very limited experience with Schneider gear so anyone has any suggestions I'd appreciate it!

Tested insulation resistance of the motor and the cable, they both passed.

Tested motor windings resistance, with all 3 windings reading around 1.3ohms

Hope that information helps

BJacqz · ‎2023-06-02

You have to know that Delta setting on ATS22 means your motor is connected in Delta And the Soft Starter is connected inside the delta of the motor (complicated drawing is shown in the ATS22 User's manual, see attached file). So as far I understand, your Soft Starter is connected on line, this is the reason it works fine with line setting.

We have improved this very much on the ATS480 including an internal test allowing to test the connection in case the Soft Starter is connected inside delta of motor

Bruno Jacqz, Drives training leader

See Answer In Context

BJacqz · ‎2023-06-02

You have to know that Delta setting on ATS22 means your motor is connected in Delta And the Soft Starter is connected inside the delta of the motor (complicated drawing is shown in the ATS22 User's manual, see attached file). So as far I understand, your Soft Starter is connected on line, this is the reason it works fine with line setting.

We have improved this very much on the ATS480 including an internal test allowing to test the connection in case the Soft Starter is connected inside delta of motor

Bruno Jacqz, Drives training leader