Air Compressor

Can the soft starter be reprogrammed with a lower current limit during starting, and yet still start the compressor successfully?

3 x 74 = 222 A. You might want to look at the overcurrent-vs-time curve of the fuses.

That is my suspicion as well.

Typically Semiconductor fuses are NOT time delay, they are intentionally designed ot act FASTER than regular fuses as a way to protect the semiconductor power devices from damage due to rapid rises in curent (DI/Dt). So typically what you do is to size them at the absolute maximum that your installation code will allow, or over size them to just provide pure short circuit protection and install a separate long-time over current protection device. Here in the US, the Motor Overload Protection in the soft starter would qualify for that purpose, so you can size the fuses for up to 1300% of the motor FLA, although typically people size them at 400%.

By the way, Altistart 48 would be Schneider, not ABB.

thank you for the advice. i will look into it. Soft starter is schneider only, i spelled it as ABB by mistake. thank you again.

thank you for the advice. i will look into it.

I would suggest trying a different Brand of fuses and use the slow-blow type to allow for more inrush time on start up. Another suggestion would be to UP the current rating of the fuse. A little trial and error may reveal the REAL problem... Good Day Mark Abell

Pls check the motor. This may be happen due to negative phase sequence current.

How long has this compressor been running for?

Has it always had this problem?

Is it new?

Have any changes been made to the piping of this compressor?