3-phase borehole pump, relay trigger delay?

I bought a couple Shelly 3 Pro for automating various 3-phase pumps. During my bench tests w/ Home Assistant I notice that the three relays aren't triggering 100% simultaneously (there is a very tiny delay as the relays engage; always in the same order 1-2-3, with approx. 0.25 seconds gap in between each relay).

I'm not sure if this is due to Home Assistant / network delays etc. causing sequential triggering... But my question:

Is there any way to gang all the three relays together within the S3Pro firmware, and trigger all relays as *one* single device / entity (instead of three individual devices / entities)?

Note: My concern is to avoid the (very small) risk of one-of-three relays not 'getting the message' from Home Assistant and my borehole pumps being forced to run on less than 3 complete phases. Many thanks!

Note 2: Yeah, my alternative option is to use a single-relay type Shelly plus a 3-phase contactor (which is probably the more bullet-proof solution).

Zitat von thgoebel

I would appreciate the “bullet-proof” solution too! Cheaper and more reliable…

Not sure if a 3 phase contactor + 1 Shelly is indeed cheaper than a S3Pro these days! All my local electrical shops are selling ABB, Hager, Schneider, Legrand etc. etc. brand DIN 3-phase contactors for anywhere from EUR 60~120 depending on spec. But I'll probably go this route all the same. Pulling up a broken borehole pump from 200m+ is a huge pain and definitely more expensive than a contactor

Zitat von thgoebel

Oh, that’s not really a bargain. Had the cheap Polish/Chinese contactors in mind while giving my guess…

lol such is life here in Portugal! Even the taxes here are taxed