So, I went to local FLAPS to have my "alternator" tested (it tested good) and they asked me if it was a generator (since it was so old) or an alternator. I said alternator. I looked it up in the PET because the guy testing it needed the part number (022.903.023 is -4) and the PET says it's a generator. What shall I call it and would that have any influence on the testing. Someone might explain the difference btw alt and gen. (gen doesn't need external current for the field windings, if I recall...)

I'm pretty sure this is a simple case of "lost in translation".


In German a alternator is called a "Generator" and my guess would be that's what they used in their factory manuals and parts catalog.

Alternator is AC current ie 120 3 phase it's converted to DC power and provides more power at lower RPMs

Generator is DC and will have output that varies greatly with RPM

Remember the 6V bugs?

It's an alternator.

--DD

Boy this takes me back. In my college days, an old guy told me the origins of all this, which goes back way before our time.

There are DC generators and AC generators. Cars had DC generators from the beginning. As electronic devices developed, AC generators came into fashion being lighter weight and I'm sure a number of other advantages.

Chrysler introduced them first and decided to coin the term "Alternator" instead of using the correct term AC generator, figuring a new name for the improved genarator would offer a marketing advantage.

Within a year or two GM decided to change over to their own AC generator and gave it their own name, "Delcotron", not to be confused with some Chrysler product. So GM cars were advertised as having a "Delcotron" on board.

So people who owned Chryslers were happy to brag that their cars had an an "Alternator" providing lights and horn, and GM owners could feel smug knowing they had a "Delcotron" doing the same.

Remember how we used to Zerox things when we were actually photocopying on an HP or Topcon machine? Well, obviously the name "Alternator" became the common term for an AC generator.

Yeah, the old Bugs had a DC generator just like my friend's '49 Ford. Our 914's are a little more modern and have AC generators and we call them alternators.

Hello?...anybody still awake out there? :-)

Good story / explanation. Thanks
Cheers Dion

....I think this explains it?
(maybe not?)it is an alternator!

Generator VS Alternator.

First some background. To generate electricity, you have to move a coil of wire past a magnetic field. The motion induces electrical current in the windings as it passes through the magnetic field. The spinning will cause the current to fluctuate as it spins due to the polarity of the magnetic field.

In a Generator, the magnetic field is created with permanent magnets. The armature is wound with wire, and a commutator assembly ( the split rings and brushes) are used to make DC voltage.


In an Alternator, the magnetic field is created by a coil that surrounds the armature. Battery voltage is used to energize the field, and the armature is turning, so it makes more voltage out than is required to energize it. The commutator is not a split ring, and the output is AC voltage. A series of diodes setup as a rectifier is used to convert the AC voltage to DC voltage that the battery can use.


Drawbacks to a generator are that the output voltage can vary. The advantages is that they don't need a battery, so you can push start a generator equipped car even if the battery is stone dead.

Like i said, i think you guys are putting way too much into this.

Ever noticed the "G" next to the red light for your alternator?

Guess why it's a "G" and not a "A".
Yepp, because the German word for alternator is "Generator" ...

but.... when the flaps guy asked if it was a generator or a alternator it would make a difference on how they would test it!!!!

Cool, haven't been up for 2 hours and already learned something. I love learning; no matter how trivial.

Well,
there is a lot of misunderstanding in this thread.
Our alternators only produce about 14-17 volts AC- not 120. A full wave bridge is used to convert the AC to DC. A full wave bridge is about 90% efficient so there is more AC voltage to the bridge than DC out. 14 AC to bridge is 12.6 DC out.
All generators do not use permanent magnets. Small ones mostly do, IE, bicycle type, and the early auto ones.
Generators may produce AC or DC, depending on the way they are constructed.
Basically for automobile use a generator is used to provide DC to charge the battery and an alternator is used for the same purpose. An alternator can produce more power out at a lower RPM due to it's 3 phase windings.
Tom

Thanks everyone. Now I have completly filled my brain with knowledge!!! It has been a long journey to get to this point. Unfortunatly, from now on every bit of new info that goes into my head will push something else out to make room. I hope I don't loose anything important in there because of this.