07-13-2013, 03:25 PM
Join Date: Nov 2012
Location: Sault Ste Marie, ON, Canada
First, some of my credentials:
Studied Electronic Engineering Technology
Graduated with Electronic Engineering Technician diploma from Sault College of Applied Arts and Technology, Sault Ste Marie, Ontario, Canada, 1996.
Have half of the final year of requirements to get my Electronic Engineering Technologist diploma, but ran out of money to continue, and this course of study is no longer available locally to me.
Iow, I know what I'm talking about regarding electricity in this situation and not talking out of my ass.
I'm not saying in any way that that's what people are doing here. We're all here to learn things, and to provide accurate information to others on a subject we all love.
I've learned a lot here from reading, now I have an opportunity to contribute information to the members that are looking for accurate information.
Now, to the current discussion.
Originally Posted by Fast Eddie
The alt produces a set amount of electrical energy, based on engine speed (there are more variables but we assume they are constant). That is then manipulated by the diode pack to convert from AC to DC and by the voltage regulator to meet the demands placed on the battery. Conceptually the alt is powering the whole electric system. In reality the battery is powering the elec. system and the alternator is maintaining the battery's amount of chemical energy. Like I said before the battery acts like a huge Cap. in this system.
In a vehicular electrical system, the battery is a power storage device, used when starting the vehicle, and called upon for power consumption when demand exceeds the power/current that the alternator (or in older vehicles, the generator) is capable of supplying to the electrical system.
To keep terms simple, we'll use the term "alternator" to cover either an alternator, or a generator.
When the vehicle is running, and the alternator is turning at sufficient rpms in order to produce enough power to allow the voltage regulator to pass the regulated power to the output of the alternator, all power required of the electrical system is sourced from the supply the alternator, NOT the battery, unless demand exceeds the supply capabilities of the alternator. If demand starts to exceed the supply that can be produced by the alternator, then the power in the battery starts to be used as needed.
The more power that is demanded from the output of the alternator, the more power it takes to be able to be spin the rotor of the alternator.
This phenomena is true and factual, because of the law of physics referred to as "the Conservation of Energy."
See https://en.wikipedia.org/wiki/Conservation_of_energy if you want a detailed explanation of this, but in a nutshell, to sum it up,
Energy cannot be created or destroyed, but can change form
The alternator changes rotating energy to electrical energy. The regulator dissipates excessive energy not being used as heat. If more energy is required, then more energy is required to spin the alternator, in other words, it becomes harder to spin the alternator and more energy has to be supplied by the engine in order to continue to turn it. Once the system is at it's maximum capacity, if more energy is needed than it can pass through, then the energy reserves stored in the battery is called upon, and added to the electrical system's capacity.
The braking system on your vehicle is another perfect example of the laws of conservation of energy. It converts the rotating energy of your drivetrain's associated parts into heat in order to slow your vehicle.
The energy doesn't just magically disappear or appear. Energy put into a system has to equal the total energy out, no matter what the system functions as.
Other examples of the conservation of energy:
Brakes convert motion into heat.
A loudspeaker converts electricity into mechanical energy, sound, and heat.
An amplifier takes a small audio signal and with adding more energy from an external power source, makes a bigger signal plus heat.