23 January 2021
Troubleshooting StF Fault on Altistart 22
ATS22 Soft Starter
The StF fault means the starter has exceeded the maximum start time setting, tLS, in the SEt menu.
tLS needs to be set higher than the ACC time.
For example: If ACC (ramp up time) is 10 seconds, then set the tLS max starting time to 20 seconds.
If ILt current limit is too low, the motor may not reach full speed within tLS limit.
Mechanical problems on the load may prevent the motor from reaching full speed within tLS limit.
See page 51 in the ATS22 User Manual
The following video is a guide for troubleshooting the StF fault code, indicating a longer than expected start-up time, on the Altistart ATS22 soft starter by adjusting the tLS (maximum start time in seconds) and ACC (ramp up time) parameters under the SET menu. tLS must be set higher then the ACC time value.