Hi there I am bored tonight and thought I could share my thoughts on your topic about alternators types.

It's my understanding that there are different types of alternators too.

The difference being in the way that some get their first "nip" of exciter current delivered from an outside source, like ours, into carbon brushes on slip rings.
That wee bit of current makes a magnetic field in the (rotating) "rotor" to cut though the outer windings of the stator, that's "stationary."
Once there is an output from the stator windings, that current is fed back into the rotor, by the voltage/current regulator device, as it monitors the system for "total" voltage fluctuations.
All excess current flows where needed out on the battery wire. There it can go and be "used" or "absorbed." Hence, battery maintenance is included.

Then there are those doing it internally.
I propose they "Picked off" the B+ terminal from the battery. This done inside the alternator, with limiting done inside the alternator and those are termed a "single wire hook up!"
Most likely without an idiot light being involved on the outside.

They all have to work the same from that point on out in its generating principles.

The outcome of how the idiot lights works only depends which type source or its direction, that comes to the bulb. The bulb doesn't care, it just get hot and is a voltage drop or current resistance in our case.

If the Bulb burns out or wire breaks, whoops!
Which is why there is a test mode we take for granted.
Past that, don't trust it! Get a voltmeter!

It's the Dash Cluster circuity that varies like where certain types of diodes are used and their placements in relation to charging units and provide charging indicator designs.
An example:
In older VW clusters, they used a Zener diode for voltage stabilization and a license plate light bulb (encased together in a unit) used like a temperature compensator, to control the gas gauge meter. Heat dissipation varies current flow through the meter.
Very cheap and effective, but that was the VW Bug! One problem, No bulb to light, no gas gauge either. Sounds familiar!

Any idiots light designs don't work if there is a small amount of voltage generated in the stator winding.

The reason is the voltage opposes the flow of current through the bulb and it dims. The lights brightness varies quickly until it's not seen.
It's like gradually making a poor ground circuit on a light bulb.
The voltage restricts current just the same as a corroded wire does.

On other alternators, the light can/could be switch on or off, while lighting a bulb, once it's below or above certain threshold level.
I do not know if that is done, at all, or within any regulator design or not?
Never studied or done surgery on a single wire Delco brand alternator or if a cluster system using an idiot light with single wire alternators.

An example of our battery warning light is like a car with one or both dim headlights.
We have all seen them on the highway, but we know you do not see them well or do they see with them, very well.

Same goes for the idiot light but it's subject to reverse interpretation of a working headlight!

A dim battery light that you cannot really see in daylight or at night, hello!
It could be burning only slightly, indicating lack of enough charge. So, it might be just maintaining a few amperes and the battery will slowly drain away.

If you cannot see it, it will not indicate to you whether it's fully charging as well.
That's why it's been termed, over many automotive years, as an "idiot light" for that very Lack of Reasoning from the bulb or its reader!

Today's cars are supplied with voltmeters, except those "economy models," that also have only "four lug nuts" on their wheels!

Over those years, there has been battles over which is better, an ampere meter or a voltmeter.

Over the years voltmeters have won because, in essence, they are more accurate!

Their safer than some ammeter circuits and cheaper to design into a vehicle.
They can be place "almost anywhere" permanently to monitor a systems health.

Ammeters are directional devices with limited capacity or are shunted in certain locations. Amounts or their readings are mostly ignored just as much!
Mostly because they suffer rapid fluctuations in order to provide very useful information and in turned is looked upon as, tell me, "IS" it in or out of the battery only?

A voltmeter works like your coolant temperature gauge.
That is, it shows when its "normal" with numbers, colored bands or a relative steady Position! But will show is it too low or in rare cases, too high.
Very much like blood pressure for our bodies!

I Hope this help explained the frustration of an "idiot" battery condition light in our cars.
Of course it was an optional dealer item like Coco Mats in the late Seventies!

Ha ha, as I remember, they looked were made out of Hemp too! Was that Yuppie cars or was it Hippie cars back then?
That's only my understanding, I am no guru on alternators but I have leaned over a few ugly grills and peered into some strange thinking!

I am aware though of 2002 Range Rovers using the alternator for a tachometer source.
Picking a winding diode inside for a DC signal source.

Talking about the changing clusters in other posts and an alternator ($450 new or $300 rebuilt) being special! The tach is engineered for alternator pulley speeds to be actual engine speed! Crazy?

No wonder their cars are so expensive! Electrics in those things really suck!

This on top of a CPS, but theirs is mounted off the front crank pulley. Easier to get too, but their several ignition coils are, you guessed it, on the back of their extra Special modified "Chevy" engine where our CPS is even harder to get to.

I don't know, is a large flywheel more accurate than a crank pulley with these Sensors or apparently no difference? They both work?


Phil