|
Tom, Some "One Wire" alternators require a fairly high RPM before they begin to charge and some can cause a small trickle discharge on the battery when setting, thats why I prefer the cheaper easy to obtain GM 10 SI Three Wire. (See wiring insteructions below) For a true One Wire its output simply wires to the Load (NOT to battery/starter) side of the ammeter. WIRING A GM 10SI 3 WIRE ALTERNATOR ON A COIL TYPE GAS ENGINE WITH NEGATIVE GROUND This is for a GM 10 SI Negative Ground 3 wire alternator to excite it to make it work like a one wire alternator. FOR NEGATIVE GROUND ONLY Run a 16 Gauge or so wire from the Ignition switches IGN output terminal (what feeds the coil when ON) or from the high input (NOT to distributor) side of the coil with a series 10 ohm 5 watt current limiting protection resistor to the lil No. 1 terminal on the Alternators side. (Excitation circuit) NOTE these ratings I use may be bigger than actually required, but the higher rated units have bigger leads easier to wire up. Thennnnn nnn even if when you turn the ignition off she still runs from backfeed, add in a series 5 amp 50 PIV Volt Diode (IT MUST be wired + anode end to switch, - cathode end to alternator). Run a 16 Gauge wire from the Alternators lil side No. 2 terminal jumped up to the big main rear output post. (Sensing circuit) It may be a lil more accurate to sense directly off the batterys + terminal, but this is much easier. Run a 10 Gauge wire from the Alternators big output post up to the Load (NOT to battery) side of ammeter (if it has an ammeter). If theres only a 12 Gauge wire from the ammeters other Supply terminal to the battery or starter etc., I replace it with a 10 gauge. NOTES: On a diesel where theres no coil and ignition switch I excite the alternator via an oil pressure switch. If the tractor uses an Idiot Light instead of an ammeter, it can be used to serve as the excitation voltage circuit to the alternators lil No. 1 side terminal. NOTES: If you�re switching from Pos to Neg ground, the ammeter leads (if it has one) need swapped/reversed or else it will read bass ackwards. NOTES: If you�re switching from Pos to Neg ground the coil needs re wired to match the polarity, i.e. if at Neg ground its lil � terminal wires to the distributor (+ from Ign Switch feed) but if at Pos ground its lil + terminal wires to the distributor (- from Ign Switch feed) John T Nordhoff in Indiana, retired Electrical Engineer
| 
