Jon the measurements were taken with the engine at fast idle(see Quote). I will set about the task of disconnection all the cables one by one, clean and tighten. I appreciate the time you have taken to work through this with me. Additionally I also appreciate all the impute I have received from everyone else. I to hope Ben weighs in here before I have to undertake the removing cleaning and tightening of all the connections. I'm still at a loss for a definitive answer as to why the inverters shut down and I'm not really fond of the shotgun approach to a problem but sometimes it can't be helped. Ben where are you??