I presume the pressure switch and pressure tank are in the well house.
As I said, it's all buried in concrete.
How about if I install a small generator next to the well house to run the well pump (and nothing else)?
How about an extension cord above ground until you get this figured out. You may need help in getting that figured out. Talk to a local friend/neighbor who is electrically or even electronic hardware oriented. An electrician would be ideal. Water for your house is worth spending money on. Computer and software knowledge won't help.
Your friend may have an unconventional approach, and I don't want to try to talk you through an unconventional approach. I am not a pro, and I still don't feel comfortable with that. One thing that could make unconventional things safer: for some panels they sell ground fault two-pole breakers. Not cheap, but if something goes wrong, it avoids injury.
Longer term, there is more than one way to consider:
- search out the broken wire or connection, and fix it. You may be able to figure out where the break is electronically, but that hard.
- run another cable to bypass the failed connection, and use a new trench. See who can make a trench.
- Make a new trench, but since it is not a lot more work and expense, put in a subpanel in the well house. This gives you lights, outlets, and more out in the well house. You will run something like 6/3 cable to the well house. This is a non-minimal upgrade
Regarding a small generator, the smallest generators are probably not enough.