What's the R connection for on a Yanmar / Hitachi alternator? Jun 01, 2010You don't say what engine or what manual you are looking at or where it is to be found but IIRC Tb training only covers positive regulation. The Hitachi alternator is however negative regulated. Maybe this diagram of the regulator and internal wiring of the alternator which I found in one of the Yanmar manuals for the YM series will help.Motor Boat Forum · Yachting Monthly's Scuttlebutt Alternator : Hitachi Automotive Systems Americas, Inc. Hitachi Automotive Systems Americas, Inc. is proud to announce the latest addition to our High Performance family, the new 1-wire 100amp Chrome GM alternator. As we did with our high performance starter line, Hitachi Automotive Systems Americas, Inc. recognized an opportunity to offer a superior product at an incredible price.