DC Motor, How it works?


You can find DC motors in many portable home appliances Automobiles and types of industrial equipments In this video, we will logically understand the opperation and construction of comercials DC motors Let’s first start with the simplest DC motor possible It looks like this The stator provides a constant magnetic field And the armature, witch is the rotating part, is a simple coil The armature is connected to a DC power source through a pair of comutator rings When the current flows through the coil, an electromagnetic force is induced on it according to the Lorentz law So the coil will start to rotate You’ll notice that as the coil rotates, the commutator rings connected with the power source of opposite polarity As it result on the left side of the coil the electricity will always flow “away” And on the right side electricity will always flow “towards” This ensures that the torque action is also in the same direction throughout the motion So the coil will continue rotating But, if you observe the torque action on the coil closely you’ll notice that when the coil is nearly perpendicular to the magnetic flux the torque action nears zero As a result there will be irregular motion of the rotor if you run such a DC motor Here is the trick to overcome this problem: Add one more loop to the rotor, with a separate comutator pair for it In this arrangement when the first loop is in the vertical position the second loop will be connected to the power source, so the motor force is always present in the system Moreover , the more such loops, the smoother will be the motor rotation In a practical motor the armature loops are fitted inside slots with highly permeable steel layers This will enhance magnetic flux interaction Spring loaded comutator brushes help to mantain contact with the power source A permanent magnetic stator pole is used only for very small DC motors Most often, an electromagnetic is used The field coil of the electromagnetic is powered from the the same DC source The field coils can be connected to the rotor windings in two different ways Parallel or series The result is two differents kinds of DC motor constructions a shunt and a series motors The series wound motor has good starting torque, but speed drops drastically with the load The shunt motor has a low starting torque but it is able to run almost at a constant speed Irrespective of the load acting on the motor Unlike the other electrical machines, DC motors exhibits a unique characteristic: The production of BACK EMF A rotating loop in a magnetic field will produce an EMF according to the principle of the electic magnetic induction The case of the rotating armature loops is also the same An internal EMF will be induced that opposes to the applied input voltage The BACK EMF reduces armature current by a large amount BACK EMF is proportional to the speed of the rotor At the starting of the motor BACK EMF is too low, thus the armature current becomes too high leading to the burnout of the rotor Thus a proper starting mecanism that controls the applied input voltage is necessary in large DC motors One of the interesting variation of the DC motor is a universal motor which is capable to run under both AC and DC power sources To know more about it, please check the next video Thank you

100 thoughts on “DC Motor, How it works?

  1. Be our dubbing partner and earn a regular income !
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  2. I don’t understand this shit I have a physics exam tom and am in 8th grade and this is gonna be one of the main contents in the exam….help

  3. I seriously don't have words to describe how good your videos are….
    thank you very much…

  4. I found this video incredibly clear and easy to understand; I am wondering how lots of people clicked on dislike !

  5. I UNDERSTAND BETTER NOW BUT I STILL DONT UNDERSTAND WHAT THE COMMUTATOR RINGS ARE FOR AND WHAT THEY DO… 😵

  6. My engineering teacher uses there videos in class sometimes, really helpful. Thanks for all the great work.

  7. In the beginning of the video you mention stator, but no label or arrow pointing to it. In the future, as you introduce each component, show a label for it with an arrow to designate it, so no assumption has to be made as to which component it's referencing.

  8. 3:05 I think Think Black Terminal sud be assigned with (- ve) Sign. Seems some mistake

  9. I hope that the rest videos are as good as this one. So easy to understand… :3

  10. My Coord Sci teacher recommended this video to my 8th-grade class, and this video really helped me understand the material! Thanks a million, mate! Edit: We are learning about energy and how motors work. Great video!

  11. Thanks to this video I can get an A in physics, thank you Learn Engineering

  12. Good video but it didn't cover up several dc motor features like armature reaction, commutation, main and additional poles, speed regulation etc.

  13. the coil should rotate in clockwise direction (flemings left hand rule)

  14. __growth tension volts growth power motor with growth turation proportionall with growth tension volts….growth intensiti amper growth power motor but not growth turation but growth intensiti electromagnetic field __archaix lord

  15. Why does the steel in the rotor had to be layered, why doesn't it come with a solid block?

  16. ___please…in a european acception exist name electric curent and name electric from cum electron name greek for chihlimbar for ellectricitti static charge this think but this nume not explicain it….but in language china electric energy is definit whit a other form at energy chi_qi and people china connsciouns and knowledge good mind this energy….____explicain….????….____archaix lord

  17. Sometimes I wonder if, when we die, it's just like life except we never get to go home and we never get to sleep we just work and work and work

  18. I have a test tomorrow and this really helped me understand why the commutator rotates. Thanks!

  19. Desgraciaus me estais jodiendo la vida con vuestras chapas

  20. Can someone PLEASE write a two sentence summary of this video? I would really really appreciate it!!!!

  21. 0:28 seconds of this educational video, dumbass spelt “which” wrong😂😂😂

  22. Wonderful explanation of the concept and beautiful done well on this effort

  23. We want a lesson from your presence regarding the thermal sensor that senses infrared radiation and how the thermal cone is done. Thank you very much.

  24. 1:43 the trick to overcoming this design flaw is actually to use AC motors instead. Tesla knew it a hundred years ago, why do these things still exist?

  25. Who the fuck labels things with the arrow pointing at the word and not the object?

  26. A SEA🌐 like topic in a DROP like time…🔵
    Great job☺️☺️☺️

  27. I am a 10th grade student. I understood this topic very clearly. Thank you so much friend. 🙂FROM INDIA..

  28. I know this might not be for everybody, please remove the words that you're speaking cuz it blocks The View of what's going on behind it or or maybe those people who are deaf, which I completely understand, just make a bigger picture so we can see both the words and the diagram don't block one from the other. Understand. Good video by the way oh, except for that stuff easy to learn from. Keep it up thank you

  29. __for learn enngineering___rot E==-dB/dt and rotH==J+dD/dt and HrotE–ErotH==div(H*E)== power motor and where is it this explication here..?? __what is difuzor ?? is it electric motor and stator is magnet and rotor is bobine circular around magnet and here not explication variation power and speed whith variation intensyti_amperaj and tension_voltage __and speed_power growth proportional with growth voltage and power growht not speed proportional with growht intensyti_amperaj __.incomplet material ___ _____archaix lord

  30. wonderful explanation..thank you soo much..continue doing such nice work

  31. I know this is a dumb question but I have to ask this.Will the motor run if the inner coil is replaced with magnets?If not,could you please tell why?

  32. Best video i have ever seen on you tube about DC motor..
    Thanks sir

  33. Please someone should help me me, my Universal motor do spark whenever I plug it into AC source
    You can reach me on Whatsapp with +2348112659304

  34. DC motor experiments in
    AC current 👇👇

    https://youtu.be/66aMCqDOEgA

  35. dear sir can you create my modified motor plz https://www.youtube.com/watch?v=P29SDY560uc&lc=z22kdj0pjwesxr1je04t1aokgvpa3ycaqpq4sqci2w30rk0h00410

  36. The rotor loops looks like the metal the thing that blends mashed potatoes 🥔 which u can use as power source to light a light bulb land power a clock

    #brown town

  37. Can someone pls explain the use of commutator… I don’t understand why we need it

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