Soft Starters for a Textile Dryer

I haven't any experience with excessive oversizing of soft-starters. Best is to get a product engineer help you determine if that's possible. Hopefully the rep would be more concerned with helping you rather than just getting you to buy another unit .

That said, in theory it will function. However, most soft-starters I know have current-limiting limits, meaning, their current-limit settings have a certain range based on their power rating. It's very possible that your existing soft-starter's current-limits are way, way over your 40kW motor's full-load-current (FLA).

Since your aim is to limit the starting current of your motor, your soft-starter will probably not be able to do it since its lowest current-limit setting would be much higher than what you need.

He's right. Most soft starters with current limit capability are either fixed (in the case of an older analog starter) or if digital, can only be adjusted down to a certain point, usually no more than 50% of their max. rating. So if you have 200A soft starter it might be able to be adjusted down to 100A, but that is still more than the 75A that a 380V motor would draw. Even so however, if you want to use them anyway because you already own them, you might be able to forgo the current limiting capability and just use them as a voltage ramping device only. That will indirectly limit the current by stretching out the ramp time, but you can run in to a limit on the amount of acceleration time you have on the motor before the overload relay trips. Just be aware though, some soft starters do not do straight voltage ramping.

You will also need to be aware of the overload protection capability of the soft starters, because they too may not turn down low enough to protect your small motors. That will mean external OL relays as well.

Gas driven internal combustion engines to replace the electric motors might be a solution