What is an alternator?

[ChevyChaser]

In the past few days, I've noted that there are threads relating electrical troubles to the alternator. Ayaw magstart ang engine pero nag crank naman...suspect: alternator. Battery lamp lights up...suspect: alternator.

Question: What is an ALTERNATOR?
How does it work?
What makes it work?
Where is it connected to and from?
WHY IS IT THERE?

Answers please!

[v6dreamer]

We'll start your tour of the alternator where it all starts in the alternator itself - at the alternator rotor. The rotor consists of a coil of wire wrapped around an iron core. Current through the wire coil - called "field" current - produces a magnetic field around the core. The strength of the field current determines the strength of the magnetic field. The field current is D/C, or direct current. In other words, the current flows in one direction only, and is supplied to the wire coil by a set of brushes and slip rings. The magnetic field produced has, as any magnet, a north and a south pole. The rotor is driven by the alternator pulley, rotating as the engine runs, hence the name "rotor." That is the alternator


There are a set of high current rectifiers in the alternator that rectify the AC to DC. A regulator controls the voltage and current into the battery. The regulator takes into account the amount of charge in the battery, and the temperature, to adjust the charging current.

Lead acid batteries are very sensitive to charge rate. They can be damaged easily.

You probably want the regulator as well as the alternator from an auto. You will have to gear up the rotation rate. The alternator need to be turning at at least 1000 RPM to operate.
electrical load. Load is created by operating vehicle accessories (lights and A/C have the highest 'demand'), as you state.

Your basic question is thus: what mechanical force operates the alternator? Response is: chemical potential (gasoline) is converted to rotary motion (engine turning crankshaft) and transmitted via pulley and belt. A belt drives the alternator.

Electrical demand places a larger or smaller load on the alternator depending on which accessories are in use. This load is 'paid for' in how much gasoline is consumed by engine.

Also, the battery essentially serves one function: to crank the engine. With the engine turning, the alternator can recharge the battery.

Finally, the alternator produces alternating current which is 'rectified' (converted) to direct current.

You should see from this explanation that the battery and alternator are complementary and not in use simultaneously.

I may not answer all the details but this is more than enough what you have been ask. Unless, if you are studying a Mechanical or Electrical Engineering I suggest you to search the book.