My recommendations.

You could use magnetic starters, or just simple relay starters which are much cheaper. They just don't provide machine protection (elec motors) like mag starters. But, if the power drops off the line for 1 millisecond, that motor or device will be dead until someone walks over & physically re-energizes it by pushing a button or spring loaded toggle. The easiest example of this would be to put one on a large (5+ hp) air compressor. As long as power is never interrupted, it will run whenever it needs to. But, if line power drops off, it's dead. I think most of the stand-bys wait about 14 seconds before switching  ON their generator power. Now, you probably would NOT want to go re-energize you air compressor if you only have 12KW, but that's OK. If you really need compressed air during power outage, better have a gasoline powered unit in the shed also. Fairly simple to wire one of those boxes for 1ph or 3ph.

I would also do this same thing with dehumidifiers in a house with a stand-by if performance is on the critical edge. I think they sell little 120V relays that plug in wall sockets & then you plug the appliance in to them. Same thing....power drops off & your dehumidifier will go off line so that your refrigerator, freezer & tv set can continue. If you are gutsy enough, go reset the dehumidifier & decide if the generator has enough oomph to handle all the load.