Yes I agree with the idea. A decent size ssr should be able to stand the surge of shutting the machine down. There are 3 phase ssR s that may be cheaper than using single phase ones but it should work either way.
I have virtually no experience of these things but although they imply that they are voltage driven I suspect they are really current driven although I haven't been able to find any data I understand.
Unless you have some auxiliary supply available such as 12v then working from nominal 48v makes life a bit difficult. If these things are really voltage driven then you need to reduce your roughly 60v down to 30 or below. It is out of the range of the typical regulators with a limit of 40v. Potential dividers are tricky unless we know something about the input requirements of these ssr s. You may have to zener clamp. If as I suspect they are current driven then a series resistor may be all that is required.
Again I don't know enough about a C60 but it seems a sledgehammer to crack a nut and although I am sure it will do it, i doubt that it will be convenient especially with the latching bit.
To me a simple voltage comparator to detect your 60v and then latch would be much simpler. Again the 60v supply causes issues and if you had some low voltage supply available then the whole thing would be far easier.
I will wait to see if anyone comes up with good ideas, preferably someone who has used ssr s . I don't have any easy way to draw circuits to post here, my scanner is a major pain so that rules out DanCad. If you are stuck I will do something.
I am inclined to think that you could adapt one of Ghurd's controllers to operate and latch a relay to power the ssr, the awkward bit being the nominal 60v.
Flux