One Wire Alternators.....

• Mad Electrical -- Alternator Tech Info

The standard OEM units are almost as simple to hook up. You just need to add a little wire and a diode or "idiot lamp" to make them work.

Advantages are less cost, and a standard 3-ire alternator starts charging at lower engine RPM's than the one-wire units.

A #194 "idiot lamp is a direct substitute for the diode, if you want to go that route.

1.) You are not understanding me. While the metal case of the rebuilt one-wire alternator you purchased may have been made by Delco, they DID NOT make the "innards" that make it "one-wire". The regulator and diode trio setup are non-standard aftermarket parts. (Delco DID make BIG semi truck alternators that will function as one-wire units.)

2.) You admit you have to "REV" the engine to get the one-wire alternator to charge. This can be a real problem with some of the older machines, if they have a relatively small crankshaft pulley and a slow-turning engine that maxes out at maybe 1400 RPM's. In some cases, one-wire alternators won't excite even with the engine "revved". That is why I recommend the standard 3-wire units that begin to charge at low engine speeds. They will work on ALL engine applications, saving trouble, returns, complaints, and comebacks.

3.) That being said, I'm glad the one-wire units have worked well for your applications, but I would not recommend them as a "one size fits all" solution to ALL old iron alternator conversions. If they are so great, why did the OEM's go through the added expense of the added wiring to make a "3-wire" system???

I buy aftermarket 1 wire and 3 wire regulators by the box of 12 and build whatever fits the application. I have never found any indication that any parts are different between a 1 and 3 wire alternator except for the regulator. The instructions that came with a box of 1 wire regulators stated that if you have a situation where the "kick in" rpm is too high with your 1 wire alternator,you need only add a the #1 excite wire to your 1 wire alternator to make it operate as a stock 3 wire alternator. The only difference being that you still do not need the #2 sense wire,as the 1 wire regulator senses system voltage internally through the diode trio.

There is a Factory stock Delco 1 wire kit designed for the 27 SI Delco alternators that fits the little 10-12SI units without modification. They consist of a special regulator and a regulator plug with a little red cap that can be inserted in 4 different positions for 4 different chargeing voltages,which seems to be of little value. I seldom use them ,as they are 5 times the cost of an aftermarket 1 wire regulator,and will slowly discharge your battery because they are constantly connected to the live battery stud. The aftermarket 1 wire regulators do not have any connection to battery power and will not drain your battery any more than a standard 3 wire alternator.