Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net> Hi All, Today I made a fairly accurate MicroSim Model of the OLTC: http://hot-streamer-dot-com/temp/OLTCigbtC-8-13-01.gif http://hot-streamer-dot-com/temp/OLTCigbtC-8-13-02.gif I change a few component values in the controller between the LM311 and the LMC555 for better control: http://hot-streamer-dot-com/temp/OLTCigbtC-8-13-03.gif Cheers, Terry