Mike W wrote:
Over voltage should be by fuse and a crowbar circuit. Do a search on
crowbar for details.

If you already have a fuse & crowbar circuit for overvoltage, wouldn't
the easy way to handle reverse polarity be a diode hooked in the
(normally) non-conducting direction across the output?
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com