Working principle of brushed DC motors

Special thanks to: Nathan Bruer, Christoph and Jon Ferran for proof reading the video script!

Table Of Contents:
00.05 Introduction
01:31 Magnetic field of a solenoid
02:23 Right-hand rule
04:15 Considering the movement of electrons
06:01 Real electromagnet
06:56 Direction of windings
08:17 Turn-to-turn fault
09:03 Rotational movement
13:09 Working principle of a commutator
16:13 Real motor with one pair of coils
16:41 Motor with two pairs of electromagnets
18:48 Swapping the polarity of the brushes
19:34 Real motor with two pairs of electromagnets
20:28 "Wrong" winding
21:54 Motor with 3 coils
23:14 Test your knowledge
The chapter on the project page:

[clo]

Certainly deserve more views.  Motor concept is more complex than people think. The only youtube video I came across that happens to be (1) realistic - no unnecessary simplified abstraction (2) complete - not skipping any phenomena or throw at you with rules or "just-because" formula (3) precise - perfect alignment and animation speed and you have no need to pause the video and ask WTH is going on (4) accurate - finally! finally a video with the physics correctly applied. Saying this video is clear or "best" is just an understatement.

There are countless youtube videos delivering the seemingly identical concept but they are either (1) self-contradictory (mixed with incorrect use of right/left hand rule), (2) straight out incorrect and misleading (applying the concept of Lorentz force from single coil onto multi poles motor - so very wrong yet get million views. I can't believe how many people have been mislead from popular votes), and/or (3) confusing (wrong arrows of magnetic field in air or through a material; no mentioning of or unclear use of conventional current and electron flows). Magnetic flux goes from S to N through a material and complete the flux line from N to S in air (some videos have the m-field the other way around - omg!). There were videos with beautiful animations but can have all three problems mixed up (unacceptable), and falsely trap students into believing that they understand the subject - then, if you were to ask them to draw out a N-pole motor rotating in a specific direction, 90% of them would quickly find themselves utterly lost in the wild half way through it, and realize what they thought they understand was incorrect and incomplete. You can plug in the equations fairly easily to calculate what current to yield what torque on a homework sheet, but the underlying physically concept is actually not at all straightforward to grasp.

Thank you for your work - your demonstration is pitch perfect. I enjoyed the 25mins ride of CORRECTNESS.

[Friendroid]

i thought i had a clear understanding of how dc motors worked...until i watched this genius presentation. This channel is electronic poetry. They say the future of TV and knowledge acquisition will be base on on-demand content, I hope i will find more channels like these, i will becomw less ignorant at every video.

[cammelspit]

There was not one unintelligible phrase to be found in this video so I assume you got the competent help you needed with the proof reading. It's a good video and I enjoyed it. Keep up the good work my friend. :)

[coloradowilderness]

Best animation. Crystal clear . Pls Do more on Electronics.
Thanks.

[kirknelson]

well done, I took electronics back in 1990, had forgotten about things like left and right hand rule for coils. its  good to have a refresher from time to time :)

[min]

Very very excellent animation, Thank you for your time make this great video

[BitBerlin]

Sehr gut gemacht. Ausführlicher geht's kaum noch.

[mayurbalwani]

Great Video!
Thank you very much for such a great quality video!
Can you please make a video on BLDC motor and its ESC?

[georgeihab]

a lot of info and nice graphics too. :)

[gingerbread]

Why can't the the current being used to magnetize the rotor also be utilized to produce electromagnets on the stator as opposed to useing permenant magnets.

[andyspoo]

Amazing work! Is it possible to use multiple windings on the same ferrite rod to increase magnetic strength? If so, how would you wind it? i.e. would you, say, wind from left to right and then wind back again, or left to right and then stretch the wire to the left and wind left to right again? Or multiple separate wires joined at the ends?

[Luca-pgmj]

but in motors with brushed brushes brushed brushes do brushes wear out? That is, if the charcoal is consumed the engine is to be thrown away? 🙄

[noweare]

This video has not got the views that it deserves.

I have 1 question that has given me confusion. I understand the right & left hand rules for determining force, field and current for a straight wire but then the wire is coiled, which direction do you use for the current since it is in a circle ?