Too Many Starts

What does SnbF mean?

The soft starter has exceeded the maximum number of motor starts allowed within a defined time period ('SLG' period, as configured by the 'Snb' parameter). This protection mechanism prevents excessive thermal stress on the motor and soft starter from frequent starting attempts.

• Motor application's operational demands require more frequent starts than allowed by the configured 'Snb' (maximum starts per hour) parameter.
• The 'SLG' (start inhibit grace period) parameter is set too short for the actual start frequency, triggering the fault prematurely.
• Control system error or faulty external sensor causing inadvertent, rapid cycling of the motor start command.
• External control system (e.g., PLC) rapidly sending RUN command signals to the soft starter's LI input terminals.

Click steps to track your progress.

1. 1

   1. Review the application's process requirements to determine if frequent motor starts are genuinely necessary for operation.

2. 2

   2. Adjust the 'Snb' (max starts per hour) and 'SLG' (start inhibit grace period) parameters to match application demands, considering motor and starter thermal limits.

3. 3

   3. Inspect the control logic (PLC/DCS program) for errors that could cause rapid cycling of the motor start command.

4. 4

   4. Monitor the RUN command signal at the soft starter's LIx input terminals for unintended rapid ON/OFF transitions using a voltmeter.

5. 5

   5. Verify the motor's load characteristics to ensure it isn't stalling or having difficulty reaching full speed, which can trigger restart attempts.