Blowing voltage regulators

Are you talking about the fusible links?
One or both?
They melt when there is too much current drawn through them as explained here
Blowing voltage regulators

Knowing which one (or both) you can look for what caused that.
if it doesn't make sense - ask.
The fusible link for the upper contact melted. So if I'm reading correctly the problem is not enough resistance in the alternator and replacing the fusible link would not solve the problem. Might as well buy one of those new alts with the built in regulators.