Alternators explained
23-01-2009, 05:12 PM
#1
Alternators explained
Want to know how they work? Grab a brew at have a read :P ,ive taken a liitle time to try and explain the basics, however i can add more info as required.
Some of you may already know ,some of you may not have a clue as to how an alternator actually produces a charge.
I hope this will help you to gain some sort of understanding into the process.
The alternator is made up from several components...
Heres what they do, i`ll explain in a little more detail later.
OK, so we need to make electricity, How can we do that?
Magnetic force can be used to create electron flow, this is the same principle as how an electric motor works, but basicly in reverse.
The stator houses three sets of windings, coild of wire in effect.
the rotor is a big electro magnet, electricity needs to be passed into this magnet for it work, this is done by sets of brushes.
When the rotor rotates inside the stator, electron flow is produced. If you were to connect a scope to this output from the stator windings you would see the SINE wave as below. This happens Three times, one for each of the stator windings we have in our stator, so in effect you lay three sine waves together giving you a 3 phase output so the wave looks like the one below..
The problem with this wave form is that it is AC, Alternating Current, so in effect it takes away the same ammount as it gives you, + - + - + -
For charging a battery this would be useless, as no charge would ever be made,
So how can we change it into DC direct current?
A diode is in effect a one way valve, electricity can only pass through it in one direction, can you see how it could be used to rectify the AC wave?
The rectifier, or diode pack is its often called, allows current to flow through it, but not back out again ,so in effect removing the negative part of the sine wave,making a DC +++++++ output. Perfect for charging a battery!
The clever part of the diode pack is that it actually uses the negative energy and reverses it ,to create even more positive electron flow, This process is called FULL WAVE RECTIFICATION
Dont be worried if you cant follow the above diagram ,its only important you can see the diodes in place ,and understand the only allow current to flow in one direction.
From there we have to regulate the ammount of electricity the alternator produces, otherwise the battery would explode! theis is done by the regulator, which takes a feed from the battery and basicly switches the alternator on and off.
FAULTS,
So by seeing the very basics of how we make charge, can you think of any possible faults?
How about this for a few
A single winding breaking down, and reducing the ammount of charge produced?
The regulator becoming faluty, and either making the alternator over, or under charge sometimes no charge at all.
A diode failure, causing AC to be produced, and may even take power from the battery when switched off , parasitic drain anyone?
Lots of these faults are caused by excessive heat, a thing we all love to produce!, exhaust housings becoming ever bigger ,and closer to alternators already stuggling to stay cool, and the need for more electricity to be produced for all the modern electronics we have fitted these days. hence why most of us will suffer an alternator failure at some point.
Hope this helps in some way, Lets discuss!
anything else you want to know more about?[/
Some of you may already know ,some of you may not have a clue as to how an alternator actually produces a charge.
I hope this will help you to gain some sort of understanding into the process.
The alternator is made up from several components...
Heres what they do, i`ll explain in a little more detail later.
OK, so we need to make electricity, How can we do that?
Magnetic force can be used to create electron flow, this is the same principle as how an electric motor works, but basicly in reverse.
The stator houses three sets of windings, coild of wire in effect.
the rotor is a big electro magnet, electricity needs to be passed into this magnet for it work, this is done by sets of brushes.
When the rotor rotates inside the stator, electron flow is produced. If you were to connect a scope to this output from the stator windings you would see the SINE wave as below. This happens Three times, one for each of the stator windings we have in our stator, so in effect you lay three sine waves together giving you a 3 phase output so the wave looks like the one below..
The problem with this wave form is that it is AC, Alternating Current, so in effect it takes away the same ammount as it gives you, + - + - + -
For charging a battery this would be useless, as no charge would ever be made,
So how can we change it into DC direct current?
A diode is in effect a one way valve, electricity can only pass through it in one direction, can you see how it could be used to rectify the AC wave?
The rectifier, or diode pack is its often called, allows current to flow through it, but not back out again ,so in effect removing the negative part of the sine wave,making a DC +++++++ output. Perfect for charging a battery!
The clever part of the diode pack is that it actually uses the negative energy and reverses it ,to create even more positive electron flow, This process is called FULL WAVE RECTIFICATION
Dont be worried if you cant follow the above diagram ,its only important you can see the diodes in place ,and understand the only allow current to flow in one direction.
From there we have to regulate the ammount of electricity the alternator produces, otherwise the battery would explode! theis is done by the regulator, which takes a feed from the battery and basicly switches the alternator on and off.
FAULTS,
So by seeing the very basics of how we make charge, can you think of any possible faults?
How about this for a few
A single winding breaking down, and reducing the ammount of charge produced?
The regulator becoming faluty, and either making the alternator over, or under charge sometimes no charge at all.
A diode failure, causing AC to be produced, and may even take power from the battery when switched off , parasitic drain anyone?
Lots of these faults are caused by excessive heat, a thing we all love to produce!, exhaust housings becoming ever bigger ,and closer to alternators already stuggling to stay cool, and the need for more electricity to be produced for all the modern electronics we have fitted these days. hence why most of us will suffer an alternator failure at some point.
Hope this helps in some way, Lets discuss!
anything else you want to know more about?[/
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