# How does an Alternator Work ?

Alternators are the workhorse of the power
generation industry. It is capable to generate AC power at a
specified frequency. It is also called as synchronous
generator. Electricity is produced in alternators
by Electromagnetic Induction. To generate electricity in a coil, either the coil should rotate with respect to magnetic field or a magnetic field should rotate with
respect to the coil. In the case of alternator the latter
approach is used. Rotor and armature coils are the two main
parts of an alternator. The rotor produces a rotating magnetic flux. Armature coils are stationary and rotating magnetic flux associated
with the rotor induces electricity in the armature
coils. This kind of rotor shown here is known as
salient pole rotor. For gaining better insight of its working let’s consider a rotor with just four poles ‘Rotor coils are excited with a DC power source. Magnetic field produced around it would
be a shown. The rotor is made to rotate by a prime
mover. This makes the rotor flux also rotate
along with it, at the same speed . Such a revolving magnetic flux now intersects armature coils, which is fitted around the rotor. This will generate an alternating EMF across the winding. Here is a slowed down version of the rotor stator interaction. For this four pole system when the rotor turns half revolution, induced EMF takes one complete cycle. It can be easily established that,
frequency of induce EMF, rotor speed and number of poles are connected through following relationship: It is clear here that, frequency electricity produced is synchronized with mechanical rotational speed. For producing 3 phase AC current, two more such armature coils which are in 120 degree phase difference with the first is put in the stator winding. Generally one end of these three
coils are Star connected, and three phase electricity is drawn
from the other ends. It is clear from this equation that, in order to produce 60-hertz electricity a 4-pole rotor should run at following RPM. Such huge rpm will induce a tremendous
centrifugal force on polls of the rotor, and it may fail mechanically over the time. So salient polel rotors are generally
having 10 to 20 polls, which demands lower RPM. Or salient pole rotors are used when the prime mover rotates at relatively lower RPM. Pole core is used to effectively transfer the magnetic flux, and they’re made with fairly thick steel lamina. Such insulated lamina reduce energy
loss due to eddy current formation. Armature winding of three-phase, 12 poll system is shown here. A stator core is used to enhance the magnetic flux transfer. DC current is supplied to rotor via a
pair of slip rings. DC current is supplied from an external source or from a small DC generator which is fitted on the same prime mover. Such alternators are called self excited. With variation of load, Generator terminal output voltage will vary. It is desired to keep the terminal voltage in a specified limit An automatic voltage regulator helps in
achieving this. Voltage regulation can be easily
achieved by controlling the field current. If the terminal voltage is below the desired
limit, AVR increases the field current, thus the field strength. This will result in an increase in
terminal voltage. If terminal voltage is high, the reverse is done. We hope you had a nice introduction on the working of alternators. Thank you !

## 100 thoughts on “How does an Alternator Work ?”

1. Paco Paco says:

Porque deta de generar electrisida

2. Pankaj Kumar P says:

Pma alternator How to magnet and coil setting video. Please??????

3. Mohan Jayaram says:

Super visual explanation

4. santhosh kumar says:

According to Faradays law current carrying conductor cut the magnetic feild. EMF will produced …..so magnet construction wise rotor winding or core….where we located the magnet

5. Marc LeBlanc says:

Fantastic explanation, simple and concise. Thank you

Hi sir

Is any type of current supplied to stator of alternator like that done to rotor of dc generator

8. Ranjeet Kumar my home video says:

hiii

9. Gammu BEX says:

So there is no use of any magnets??? How DC voltage is generated to excite the rotor coil???

10. Jagannathan K says:

I liked the explanation very much.
Thank you for this video

nice, I understood nothing

12. Pedro jesus Hernández olivares says:

Espectacularrrrr explicación..

13. Gammu BEX says:

And the DC exciter needs the permanent magnet what voltage is going to the exciter coil of generator from small DC exciter??

14. manikandarajan 3D says:

finally i got answer ,thank you…

15. Captain Aravind says:

Hysterisis motor , other motors needed

good tutorial sir

17. Memphis Bend says:

It didn't take long for me to get lost ! However, this is a great educational video thank you. I will continue to try to work it out !

18. VOICE CREATE says:

Wonderful lecturer an alternator

19. hari haran says:

Hi super explanation

20. ShI VaM says:

Nice

21. Samit Kumar says:

Thank you verry much

22. Uvrao Chowdary says:

Excellent animation!!
Thank you, Sir!!

23. ARYN SCHROEDER says:

I UNDERSTAND 3-PHASE POWER, I'D LIKE TO KNOW WHERE A PERSON CAN FIND A SELF EXCITING 3-PHASE ALTANATER? WHEN I BUILD MY DREAM HOUSE, I WANT TO BE SELF POWERED, I WOULD USE TURBINES TO RUN ( WITH WATER) THE SAID ALTANATERS.

24. Javier Ferrer says:

25. Ganesh DaBLiYu Lal [W] says:

Why rotor is connected with DC source??

26. Abdullah Qayyum says:

really good explanation.

27. ajay munda says:

Nice. ..

28. Uche Presley says:

Can you help understand better, how many D.c volt is added to produce such a high a/c volt.?

29. Basic Knowledge says:

nice

30. Tanner Bennett says:

NSC2019

31. x- o says:

The watermark is distracting. Try again.

32. Tapan Modi says:

This is possible or not? In generator stator side we give AC input so as time varying magentic field is vary and so chainging magnetic flux is Link with armature and emf is produced So here there is no need to rotate the rotaer to turbine?

33. davin ross says:

support me so i can support you

34. ANNEPOGU SUMANTH PAUL says:

Very nice explanation. Thanks for the video

35. Mohd Inam says:

Why it is called synchronous generator I mean what actually is synchronous?

36. Tommy Bear says:

way more complicated that I expected. who tf comes up with this

37. Vicky Rao says:

Hindi hoti to OR mja aa jata bhai

Cool

39. venkeswar v says:

Excellent explanation .Very much useful.

40. xamo says:

Energy from magnet can be obtained without any mechanical movement. All we need is material capable of being converted from magnetic to nonmagnetic when applying electrical impulses. This will simulate the rotation of the armature in the generators. Such a material was created for other purposes and there is technology. More info ?

41. Fernando Daniel says:

Tan bien explicado que lo entendi hasta en inglés

42. Abul hasanat says:

if we supply AC instead of DC for excitation what will happen?

43. Veerapalli Rohith says:

Good

44. KULDEEP YOGESH TIWARI says:

भारत से आपको बहुत सारा आभार😇

45. TheAmazingJimmy says:

So, will this generate more power than what is supplied? If not, why bother?

46. Thulani Nxumalo says:

I wish youtube was still there during my days at school.

47. Brendan Laven says:

Are you sure that's not a turbo?

48. Balázs Perger says:

🙁

49. İlhan Yıldırım says:

Thanks for Turkish translation.

Okay so does the small DC alternator on the far right make energy for the alternator Main Power's Magnetic field?

51. Slim Cognito says:

This looks like a hell of a lot of copper

It really very help to learn me.

And through animation easily understand.

54. Knee deep in the Water somewhere says:

Does this thing take electricity to work?

55. Harshit Singhal says:

56. Diptarup Saha says:

direction of dc current in rotor pole is given wrong

57. Jonty Tailor says:

58. Dne Tne says:

Hope you had a nice introduction…WAIT A SECOND

59. ksr bana says:

But how get the output

60. Pertamax7 says:

Ok sir

61. praveen kumar says:

I want alternator winding book. So please tell me

62. Kyle Ayton-Laplanche says:

why does the outside remain stationary? can you also spin the outside opposite from the inside?

63. Hayat Umar says:

السلام علیکم و رحمت اللہ و برکاتہ
Thank you sir
My WhatsApp number
00966565958304

64. Sandy Singh says:

I request you to also show the subtitles because of your American accent​ sometimes it become difficult to figure out some words.

65. Javier Enrique Vasquez Lopez says:

Excelent video, thanks

66. Elvin callistus lopez says:

thankyou

That's how mafia alternator works !

68. Akash Gupta says:

For constant freq. the prime mover needs to run at constant speed. what if the prime mover turns at slow speed? AVR?

69. Khelfaoui Abdelbasset says:

Thanks,great explan i wich you give us a lot of video like this for easly ..

70. luigi ionascu says:

__rot E==dB/dt and rotH==J+dD/dt and HrotE–ErotH==div(H*E) and where is it this here…?? in work of alternator_engine_motor of ellectric power but this formula is not here videoclip describe_ ____archaix lord

71. William Dukane says:

Good video, but the audio seems to have some weird glitches. Also, it sounds like the writing was done by a non-native English speaker because there are some odd errors.

72. Islam Deraz says:

Good explanation but I need more about asynchronous alternators

73. Abu bakarr Sawaneh says:

Which software you are using to make this videos.

74. KULDEEP YOGESH TIWARI says:

My name is Kiyugardi alternator Fakiro

75. Ferdus hasnat says:

Thanks a lot

76. Ghazi Khan says:

Wow

77. Abdul Chalik Maseran says:

How much DC voltage do you need for your rotor so that it can produce an electro magnetics field?

78. Women Should Be Slaves says:

Why is the voice over guy usually so boring?

79. SkullKID says:

Shouldn't the currents in the rotor windings be alternating between clockwise and counter-clockwise at 1:25?

80. Fabio Camargo says:

Very good this vídeo l love so conglatulation for the vídeo friend thank you!

81. MY Exam says:

हिन्दी में उपलब्ध करे sir

82. Donald Sleightholme says:

i had a idea for a electric vehicle with five wheels? use the fifth wheel to turn the alternator and charge the battery while driving? 🤔🚗🔋🤷‍♂️ (with a step down transformer and a rectifier) 🤗

83. Nikhil Shukla says:

Thank you

Where is the electricity coming from though?

Thank you for producing this very helpful guide to the inner workings of alternators.

86. Paul Zed says:

I don’t think it generates,
It collects electricity.

87. Virtual Element Studios says:

Nice

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88. Ayaz Borkar says:

Amazing sir. Thank you so much

89. Nicholaus Julius says:

Thank you for this tutorial.

90. Hossein Fatehi says:

Very good

91. Hussain Ali says:

best explanation then my professor who just confused me.

92. OnixTV says:

So to turn a car alternator into a motor you need to apply ac current to the coils, and dc current to the brushes?

93. Dwaipayan Datta Roy says:

94. Omar bou Muhammad Alhamdoulilah says:

Thanks

95. svwtsvfcb says:

So basically an alternator is a reversed synchronous motor, no?

96. Pk Singh says:

Loved it.

97. Pk Singh says:

Loved it.

98. Red Squirrel says:

How is each phase regulated separately? Say you put a large load on only one phase so you need to bump up the magnetic coil voltage, will that cause the other 2 phases to have too high a voltage? Or do you just regulate based on the average voltage and slight imbalances are just tolerated? The more loads on the system the more balanced it will be so it will probably matter less.

99. B. Saheb says:

AVR means?