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How an Alternator Works

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Old Nov 15, 2017 | 04:53 AM
  #1  
speedkar9's Avatar
speedkar9
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Default How an Alternator Works

I made a short video on how the alternator works in your car. Check it out here:


The job of an alternator is to generate power to charge the battery. It turns mechanical energy into electrical energy.
This is the alternator I pulled from my Toyota Corolla:
How an Alternator Works-27tqpeu.jpg
The alternator is powered by the crank through the serpentine belt. This pulley turns the rotor inside:
How an Alternator Works-shptzht.jpg
On the back of the alternator is the rectifier (gray) and the voltage regulator (brown).
How an Alternator Works-r8p60om.jpg
Once the front of the case is opened, we can see the rotor inside the stator.
How an Alternator Works-93jcbze.jpg
The rotor consists of field windings wound around an iron core. The triangles are called finger magnets, and oppose each other in polarity. The rotor acts as an electromagnet when powered up by the voltage regulator and causes the stationary stator to induce current. Kind of the reverse of an induction motor.
How an Alternator Works-jazpmpt.jpg
The stator consists of three independent coil windings that are 120 deg phased apart. When the salient pole electromagnet rotates inside it, it induces an alternating current, because of the alternating poles. Three phases of current are produced, spaced 120 deg from each other.
How an Alternator Works-gtltdcq.jpg
The rectifier is responsible for taking that alternating current and turning it into direct current to charge the battery:
How an Alternator Works-p23zfoi.jpg
The voltage regulator is responsible for regulating the voltage going to the battery so It doesn’t discharge or overcharge. It powers the electromagnet (rotor) that rotates in the stator
How an Alternator Works-ycctizo.jpg
And that’s all the components in an alternator, its pretty simple and straight forward!
How an Alternator Works-bs4hacb.jpg
References
https://www.freeasestudyguides.com/e...er-bridge.html
http://www.carparts.com/classroom/charging.htm
http://tiptopmetaldetectors.com/meta...etectors-work/
https://www.justanswer.com/toyota/73...regulator.html
Enjoy
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Old Nov 15, 2017 | 08:32 AM
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Sir, I think you deserve your own section called "SpeedKar's DIY Zone".

Thanks for sharing! Had to replace one of these suckers on a H22 motor.
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Old Nov 15, 2017 | 09:02 AM
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Something to note as a potential weak link is that many of the newer alternators drive pulley has a one way roller sprague clutch which can either lock or freewheel depending on its failure mode.

If your vehicle stops charging, pop the cap from the pulley and with the engine running verify the shaft in the center is turning....

The repair cost is $40 vs $400+++ for a new alternator.
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Old Nov 15, 2017 | 10:25 AM
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I love these play by plays. So very informative

You could be an Automotive teacher.
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Old Nov 15, 2017 | 07:14 PM
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speedkar9
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Originally Posted by mk416
Sir, I think you deserve your own section called "SpeedKar's DIY Zone".

Thanks for sharing! Had to replace one of these suckers on a H22 motor.
Originally Posted by Hoovey2411
I love these play by plays. So very informative

You could be an Automotive teacher.
I'm glad you enjoy these break downs.
Thanks for the suggestion, I've added Automotive Teacher to my resume
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