Kathy Loves Physics & History - 2021-12-26
Who invented 3-phase electrical distribution? Nikola Tesla? Mikhail Dolivo-Dobrovolsky? In this video I go through the detailed history from primary sources of this important EE discovery, how it works, and why it is important. Links: My mailing list (with a link for a video on the history of 2 phase) https://kathylovesphysics.ck.page/welcome My Patreon Page: https://www.patreon.com/user?u=15291200 As usual, a big thank you to the fabulous Kim Nalley for singing "electricity" and some background music. www.kimnalley.com Citations: Alfred, R “Aug 14, 1888: I Sing the Meter Electric” Wired Magazine (Aug 14, 2008) Thompson, S Polyphase Electric Currents and Alternate-current Motors (1900) p. 444 “Mr. Nikola Tesla on Alternating Current Motors” The Telegraphic Journal and Electrical Review vol. xxiv (June 7, 1889) p. 648 Carlson, W Tesla: Inventor of the Electrical Age (2013) p.113 Tesla, N “Tesla’s Tribute to Westinghouse,” The Age of Steel LXXXVIII, no. 10 (September 1900), 9. William Stanley “The Induction Motor” Engineering News (Oct 2, 1902) vol. XLVIII No. 14 p. 279 Frank Sprague to Sprague Executive Board (leaked to Edison) (April 29, 1890) Edison Papers Digital Edition [X120CBN] Jonnes, J Empires of Light (2003) p. 223 Leupp, F George Westinghouse: His Life and Achievements (1919) p. 159 Skrabec, Q George Westinghouse: Gentle Genius (2007) p. 130 “Mikhail Dolivo-Dobrowolsky (1862-1919)” [in Russian] Vavilov, S People of Russian Science: Essays on Outstanding Figures of Natural Science [Люди русской науки: Очерки о выдающихся деятелях есте- ствознания и техники] (1948) Dolivo-Dobrowosky, M "Transmission of power by rotary-phase alternate currents", Electrical Engineer (London), vol. 7, p 369, (April 10, 1891) “The invention of the electric motor 1856-1893” Elektrotechnisches Institut (ETI) https://www.eti.kit.edu/english/1390.php Thompson, S Polyphase Electric Currents (1900) p. 173 Thompson, S Elementary Lessons in Electricity and Magnetism, (1894) p. 507 Ushakov, V “Electrical Power Engineering” (2017) p. 16 Allerhand, A “The Earliest Years of Three-Phase Power” Proceedings of the IEEE vol. 108 (Jan, 2020) p. 215-6 Herausgegben vom Vorstand der Ausstellung Offizieller Bericht über die Internationale elektrotechnische Ausstellung in Frankfurt am Main, 1891 (1894) p. 324 Lightning: Volume 1 (April 28, 1892) p. 509 “The Transmission of Power at Frankfort” The Electrical Engineer (Sept 18, 1891) p. 286 Brown, C “Reasons for the Use of the Three-Phase Current in the Lauffen-Frankfort Transmission” The Electrical World (Nov 7, 1891) vol. XVIII No. 19 p. 345 Nikola Tesla patent US 382,280 “Electrical Transmission of Power” (May 1, 1888) “Mr. Tesla’s Experiments” (April 6, 1892) Electrical Engineer vol 13-14, p. 350 Lamme, B “The Story of the Induction Motor” (March 1921) Electrical Engineering (New York) vol. XL p. 205 Tesla’s patent was co-owned by supporters Alfred Brown and Charles Peck, according to Carlson, B Tesla: Inventor of the Electric Age p. 130 “Since they had shrewdly handled the business negotiations and assumed all of the financial risk in developing the motors, Tesla gave Peck and Brown five-ninths of the proceeds from the deal while retaining four-ninths for himself” Lamme, B Benjamin Garver Lamme, Electrical Engineer, An Autobiography (1926) p. 61 Lamme, B “The Story of the Induction Motor” (March 1921) Electrical Engineering (New York) vol. XL p. 212 Davis, L Fleet Fire: Thomas Edison and the Pioneers of the Electrical Revolution (2012) “Westinghouse paid Tesla $216,600” “Annual Report of the Board of Directors of the Westinghouse Electric” Electricity (June 30, 1897) p. 387 Gordenker, A “Japan’s incompatible power grids” Japan Times vol. 19 (July, 2011) p. 9 Dolivo-Dobrowolsky “Transmission of Power by Rotary-Phase Alternative Currents” The Electrical Engineer (April 3, 1891) p. 336
I didn't know about Dolivo-Dobrovolsky's greatest inventions until today( I never heard about him either). Thanks to you Kathy now I know who really invented the most practical and efficient 3-phase AC. Dolivo-Dobrovolsky is so under rated ! 3-Wire 3-Phase !! What a genius !
YUP, but is it a Y or Delta (meaning a triangle) which came first? Is the Y better for
lighting or motors? A Delta can have a center tap in the midst of a winding to give
120 volts while a Y will give 1.732 X the voltage from phase to phase as compared to
the voltage from the neutral or one side of the three windings to a phase conductor.
@@raymondgarafano8604 With the D-configuration you will have the main voltage across the windings at all times (centre tap to 120V is an abomination that offers no real advantage except an insignificant reduction of insulation needed), but you won't have a neutral point.
Thanks to your presentations Kathy, as a retired electrical engineer, I am still exited about the beginnings of the sciences and their industrial implementation.
Excited vs exited 😊
@@colmcillegardner2144 thank you ☺
As a Polish electrician and electronics hacker, I'm proud of Dolivo-Dobrovolsky and absolutely delighted with this episode :)
Oh, and there are a few other important Polish inventions in electrical engineering: a FW bridge rectifier (or, as Electroboom would call it, FULL BRIDGE RECTIFIER!) and an electrolytic capacitor - both invented by Karol Pollak. How would electronics look now if not for him? I guess we'd still go with the centertapped windings.
To think that most of the principles and inventions lied out by him are the mainstay of modern electrical distribution systems, though now that we've got highly efficient DC/AC converters, we may be seeing some DC power system resurgence especially in the international ultra high voltage networks, not to mention the solar installations. DC switching on the other hand, arc quenching in particular... makes me wonder if it can be easily solved using IGBTs or FETs (thyristors won't do, they stay latched until power is cut off, making them useless for this purpose).
Simply put, this is a better explanation of these events, than I heard in my EE Engineering classes at UCLA, LOL. Kathy, I do not know your history, but you were, imho, born to teach:) Thumbs up across the board.
Thanks so much
If a YouTube content creator Does a better job at explaining electrical engineering, Then a professor at UCLA… Than why the heck is college so expensive???
@@Dennisaj excellent question, the answer is something called 'tenure' :)
I 100% agree. This is like 4 or 5 different lectures and probably more than 2 or 3 classEs. Power systems and electromechanics was my favorite subject and I never heard all of this together or this organized.
Well,
There is a huge difference between teaching "History of science " and actually doing or teaching science ...huge difference.
Anybody notice how all of these geniuses are almost always immigrants? That's what keeps America young, vibrant and great.
Well, yeah! All of us were then.
Speak for yourself! I’m no immigrant, nor am I a genius! 😂
Yeah, but any racist xenophobe knows we’ve had the perfect amount of immigrants. The BEST immigrants, too.
Yeah, but any racist xenophobe knows we’ve had the perfect amount of immigrants. The BEST immigrants, too.
Yeah, but any racist xenophobe knows we’ve had the perfect amount of immigrants. The BEST immigrants, too.
Kathy, the difference you're pointing that Tesla's three phase motor needed 6 connecting wires and Dolivo´s had only 3 makes a world of difference and thanks to you I can see where these two
inventors differ and the huge Dolivo-Dobrovolsky´s breakthrough. How elegant is Dolivo´s 3 wires solution; I'm in awe !. Thank you for helping me see it so clearly !
Invention is needed in order for refinement to occur.
"Doliwa - is a Polish coat of arms. It was used by several szlachta families in the times of the Polish–Lithuanian Commonwealth."
Dobrowolski is the family name and you can translate it as "Goodwill".
But i agree that is very well made video and amazing work made by Kathy.
@@Bialy_1 O tym że system 3-fazowy to wynalazek Polaka to wiedziałem, i tą wiedzę propagowałem. Ale co to jest 'doliwa' to już nie. Dzięki.
In fact, this is a key observation, I just saw the full episode and I was angry on so many years of misinformation. Tesla added his 3 coils variant as a variant of the 2 phases device, no study really in the background. As a filling of possibilities in the patent. He did not know the huge difference between 2 and 3 phases. In fact, all that we use today is the AEG system, so is clear for me in one moment the Americans understood but was no way for them to recognize it... Tesla himself probably knew it best.
@@costiqueR Exactly. Tesla did not know the HUGE difference between 2 phases and the REAL (Dovrowolsky´s) three phase with only three wires.
Not only do I now understand the history of this form of energy distribution, I finally have a better working understanding of the manner in which AC works in modern systems. Great job, Kathy. As a retired middle-school Natural Sciences teacher and junior college Horticultural Adjunct, it's wonderful to see someone explaining science in such a meaningful manner, using original sources. Pray, continue!
I worked at a power plant for 35 years and studied the basics classes back then. At the first power plant i worked at it was very old unit . The equipment worked well but has long since been removed. Glad i ran onto this channel. I certainly watch more of your videos . I remember i think that air craft were a lot higher frequency . Thanks for the history lesson..
As an industrial electrician for over 40 years, I routinely worked with 240 volt and 480 volt 3-phase systems. The 3-phase systems were not all the same. Some were configured as "wye" and the others were configured as "delta." To top that off, in one factory in which I worked, they used a 240 volt 3-phase system with one of the "phases" (conductors) grounded. This was called a "grounded B-phase system." Most factories do not use this system.
Excellent videos, Kathy!
480v ?
@@RecordProduction American 3 phase system
No, the grounded B-phase system was 240 volts. The factory also had 480 volt, 3-phase systems that had the normal ungrounded conductors. Thank you.@@RecordProduction
Yes, 480 volts. Some of their 480-volt, 3-phase systems were 480 volt / 277 volt, wye connected systems.@@RecordProduction
Dobrovolsky's contribution in the development of 3-wire 3-phase electricity was really an eye opener for me as I had all along thought that Tesla was the sole inventor.I had known of the contribution of Steinmetz however.
This is all bull. Specially coming from a woman. Tesla invented ac period
@@europoamerico7605 Nope he didn’t. It was invented years before he was born.
@@europoamerico7605 from memory the first ac was generated by a French woman using a Faraday designed machine. The commutator was introduced to this machine by Andre-Marie Ampere, thus producing the first generated, rudimentary dc.
It doesn't change much whom invented what.
Tech should be available to everybody,but now days Tech has become only profits and no benefits for everyone, but the end results its the same.
Tech make rich some and screw over the rest,a truly excellent tech is the one that once built last over time and not break after 1 2 years due to the fact that Markets need something new every few months to make more profits...
In the facts is the human kind greed that is driving today's world,along with non stop pollution of the planet.
On which we all live and when the planet dies we all will die with the planet..
Capitalism and Political Corruption...
🤣🤣🤣🤣🤣🤣🤣🤣🤣
@@europoamerico7605 This is sex discrimination!
I thought I knew this history. The Westinghouse+Tesla vs Edison story is very familiar to me. I had never heard of Dolivo-Dobrovolsky. Thanks for clearing up the details of how 3-phase became dominant electrical distribution system.
X2. I thought Tesla was the only one and the creator of virtually everything
Same! Feels like his innovation was more impactful than either of edisons or teslas.. and impressive that it has stood the test of time as well!
There was no Tesla V Edison
@@kevinmithnick9993 Well, you were wrong. Tesla invented only 50% of everything, the other 50% was invented by Da Vinci.
@@wiadroman Well, 50% of everything is still a lot. Is sad nowadays we are more worried who is taking more attention than who is doing more. Yes, there is a difference. Good to see at least 0.000001% of world population devotes their lives to human adavancing as civilization. Unfortunatelly that number is in decline
In all my 50 years being in electronics with a bachelor's degree in electronic engineering, I never knew the information you just presented.
I'm impressed ,and decided to subscribe.
I don't know why the YouTube algorithm sent you my way last week, but I'm glad it did. The level of detail and citation you go into is wonderful, and you're a great story teller. Too much of what gets taught in science classes about the history of science seems to be more like folklore, so it's wonderful to find someone who digs in to get the details right.
She is a great teacher.
Thanks!!! If young students were tought all these stories we would have more engineers... and we need them
Thank you Kathy. I am so grateful for your work. There are many excellent science educators on YouTube but your thoroughness and uninhibited passion set you apart. Your videos will play a part in my child’s education.
Awesome job !!!!!! I build electrical control panels for several clients including Westinghouse Nuclear (worked as an engineer for them a decade ago). Your timeline is sooooo much clearer than any I had read. I also did not know where the 50 vs 60 Hz came from ... loved that part of the story! Thanks so very much !!!!!!
Kathy - A very informative video. I love the history and reasons behind what we use today. I used to be a volunteer at the Folsom Historic Powerhouse in Folsom, CA. It was built in 1995 and we told our visitors that it was the first long distance 3-phase powerhouse in the US. It was built just a bit before the Niagara Fall powerhouse was put online. Niagara used Westinghouse 2-phase generators. I believe that GE got the power transmission contract to Buffalo and used Scott-Tee connected transformers to convert to 3-phase. It's interesting that the Folsom powerhouse has four 3-phase generators and used 12 wires to send the power 26 miles down to Sacramento. This was because the original governors were not stable enough to allowed the generators to be synchronized. The AC was converted to DC in Sacramento with M-G sets and then paralleled in order to power streetcars. The change to Lombard governors in around 1906 allowed the paralleling of the generators. Folsom used GE generators. I believe this was because the Livermore Brothers used financing by GE in order to build the powerhouse.
That is fascinating! I read somewhere, I think Allerhand, A “The Earliest Years of Three-Phase Power” Proceedings of the IEEE vol. 108 (Jan, 2020), that Westinghouse lost out on the Folsom gig because he refused to use 3-phase! It is fascinating to me that Westinghouse was so advanced and adventurous with AC versus DC and then so resistant to 3-phase.
@@Kathy_Loves_Physics As a Professional Control Systems Engineer, and powerhouse docent, I'm familiar with some of the older technology but never learned much of the history. Thanks for combining the two in an interesting way.
Hi Jim,
Well now I'll have to visit, if still open, I'm in Citrus Heights and driven by often. Thank you for reminding me of fascinating things right near me.
@@Kathy_Loves_Physics Follow the money trail where a reason might be for this (his) reluctance.
My sis lives in Orangevale. The first time I was visiting years ago and biked on the bike trail along the American River I noticed the 'strange' building. Then I found the web site about Folsom Power Station. Now I recognize the face of the man who runs the site - very informative, and big thank you. I had no clue it's one of oldest hydro power houses in North America.
As for the 3 phase system the one used in Europe (at least in Poland and German speaking countries) is a bit different from North American, that most of the buildings like farms, small shops, receive 3 phases 380V, in order to run 3 phase motors equipment. Most new houses are also 3 phase ready. No need for strange rotary phase converters or transformers in order to run lathe or milling machine in garage ;) - thanks to Dobrovolski and AEG. I guess two phase residential system is cheaper to build and that is main reason it remains in use until today. BTW, in Canada from time to time I see 230-240V European single phase devices run from 2 phase system: other than speed in case of motors, no real issues such as overheating.
I have never said this lightly but I love you! Your channel lit a fire in my heart over a year ago by showing me that electricity isn't as complicated as it looks on the outside while still having a close to limitless amount of uses that people would believe was just a load of fiction if they didn't see it with their own eyes. Because of you I am currently halfway through my freshman year in college majoring in electrical engineering followed by big plans based on the future uses and generation of electricity
That makes me so happy. I’m sure you are going to do amazing things and I am honored to be a part of your story.
Cheers,
Kathy
I am so glad that I happened upon your channel. Back in the 70s, my uncle, who had been a printer since the 1920s, called me for help. He had an ancient printing press that was needed for an important production run. There was something wrong with its motor and control system - its two-phase motor and control system! This was the first I had heard about two-phase as I only knew about single-phase and three-phase. This ancient machinery looked like you would expect early 1900s devices and controls to look like. Somehow I figured out what was wrong and got it all working. That was my first and only exposure to two-phase power. Thank you so much for this terrific history lesson. You have a new subscriber!
You can create the second phase - which has a 90 degree phase shift - with a capacitor.
I was surprised a number of years ago that I noticed a 2 phase motor at the scrap yard. It was for sale, but I obviously had no use for it.
Two phase can be made from single phase, but I'm not an engineer to discuss this. Lancaster Pennsylvania had been wired for 2 phase many years ago, and this motor was evidently from that era.
@@Farm_fab interesting
. So there's a scrap yard where one can browse in Lancaster? I'm in nearby Palmyra, could tell me where this is? Thankee
7
This is the best video per minute of time I've seen on the history of this subject by far - good job and thank you.
Thank you for the lovely comment. Made my day. 😊
@@Kathy_Loves_PhysicsIll have to agree with mr or mrs Vapors,,, I have been an electronics engineer repair guy tinkerer and instrument maker and now in my 60s still doing work in film and i have to say your videos are really enjoyably to watch and this old dog has even leaned a few new tricks ( or at least history) of a few things even i did not know.. Thanks for taking the time and effort to do these vids and research all this wonderful history. I love your style and enthusiasm telling these stories. keep it up!
@@Kathy_Loves_Physics Nicola Tesla is not serbian. When asked by a reporter where he was from, he said Austro-Hungarian which the area is current day Croatia.
I have worked on and designed 3 phase systems for 30 years. I cant count how many books and papers I have read on the subject and this video had me rethinking a lot of what I have learned. Thanks for all the hard work researching this.
I will second that opinion. thanks Kathy! I just found your channel and will go to watch the rest of your vids. may I humbly suggest to wear a microphone I can better hear your lovely voice and content 🙂
Very well done. People usually think I'm a weirdo when I start talking about 3 phase power...I think "most" people literally don't even know it's a thing. I used to have a big old warehouse building that was fully electric in 1910, it had modern power service but all of the original 1910 3 phase knob and tube stuff was in place and disconnected. Incredible to look at and see how advanced it was for the time. The distribution board with the slate back and live knife switches looked like something from a movie set. At over 100 years old, add some plastic insulation and change fuses for breakers and it's an almost identical system to what we are still using today.
The original light switches were all rotary - this is why we say turn on the lights when we mean flip a switch. They have a neat little window with the word on or off when you turn it.
Fun fact:
The 18th of December 1893 the worlds first commercial 3-phase power transfer was inaugurated. The transfer line ran between Hällsjön (the source, water turbine IIRC) and Grängesberg (at the time one of the largest iron ore mines in Europe) in southern Dalarna, Sweden. The distance of the transfer was 13 kilometers and transferred up to 9300 Volt. Remains of the facilities can be seen to this day.
A testing and demonstration facility connecting Lauffen and Frankfurt in Germany had been in operation for a few years before.
Jonas Wenström is sadly unknown outside Sweden.
You always create exactly the right mix between illuminating personal motivations and technical background that makes following the subject not only a breeze but very enjoyable.
You should do a video about the frequency of the line. Motor users wanted lower frequencies, and lighting wanted higher frequencies. Various grids were from 16hz to 100hz over the years and finally settled on 60hz after WW2. Also there' a national time keeper to keep track of the number of 60hz transitions per day and run the grid a little faster or slower at night to "catch up" so our bedside clocks stay accurate. Lots of stuff about this that would be right up your alley!!
Fascinating stuff, especially as I worked as a design and test engineer for a transformer manufacturing company way back in the 1970s.
I couldn't do history to save my life at school, but I love the history of science and technology.
I'm surprised I wasn't taught this in grade school, but I learn it 50 years later from this wonderful lady who loves physics & history.
I'm not. As interesting as it is, it's not really something you learn in school. I do not know what you studied. But if you studied history, that's a bit too electricity-specific to be learned. If you study physics, it's more a historical thing than an electric thing.
Now, if you study the history of electricity, I'm with you, you should have learned that!
Kathy, I’m brand new here, but the research and delivery of information is nothing short of AMAZING! I love that you don’t waste our time with wasted B-roll videos and other stuff. Your information and expertise is why we are here.
Thank you, Thank you, Thank you!
(One for each phase :P)
You’re welcome you’re welcome you’re welcome… and thank you for the nice comment
I really like listening to someone who is so comfortably versed explain a topic. Thank you.
8:57 Thank you, great video as always. I can remember long ago asking (pre-internet) who created this crazy star delta stuff (which is brilliant) - now I know Mikhail Dolivo-Dobrovolsky.
It really is amazing isn’t it?
Kathy thanks so much for putting this up , ive been in electrical / mechanical engineering for 40 + years and you've taught me stuff i did not know ( i double checked ) , thanks for putting me right , liked and subbed , thanks again .
Great video! I'm electrical engineering student and there is a lot of talk about Michał Doliwo-Dobrowolski at my university. There is even a statue of him near the building. I wonder how many underrated scientists there are, who didn't have the political circumstances to become globally known.
It was the electrical engineer Dobrowolsky, from the AEG firm in Berlin, who, persisting in his research into alternating current motors, filed a patent application in 1889 for a three-phase induction motor with a squirrel-cage armature with excellent starting torque and an efficiency of approximately 80%. The efficiency of the two-phase motor was 50%. I would like to say that I really like your work in terms of knowledge and the clarification of the truth.
Long live Dolivo Dobrowolski, Forget Nikola Tesla. This great discovery. Even greater than all the discoveries of Nikola Tesla. Well done, dear lady, for opening our eyes.
I like two things about this channel.
1) The willingness to have a balanced view about history,
eschewing the common practise of fixating on just
the well known players (ie Tesla/Edison etc) whilst
ignoring the contributions of others who were pivotal
especially from a practical perspective.
2) The presenter - Kathy, you are just so damn watchable !
Don Unruh
Amen to that!!!
I just discovered you channel. It is great.
As an American, I thought I was taught the whole story of electricity. But came to realize I only knew the American version and much was deleted or skipped entirely. American versions of history tend to exclude all others. People like Dolivo Dobrovolshy are completely overlooked. Maxwell is said to have moved to America in some books I read. Untrue Thank you for filling in all the true details.
The English do that too. Americans only copied the idea from the English ;)
@@millomweb No, you're wrong. We give credit where, (and to whom), it's due - Xenophobic tunnel vision, (and selective recall), tends to be a largely American, (and to a lesser extent, Russian), phenomenon, (although I concede that Russian originality of thought and technical prowess puts that of Americans to shame .. you really didn't do very well with rocketry, for instance, before Von Braun launched 'Explorer' for you, (all credit to you Yanks for that, of course; good 'American' name .. 'Von Braun' ..), on top of a Redstone rocket, (essentially, his A4/V2 on steroids, just AFTER the launch of Sputnik 1). The English, (and in case you hadn't guessed, I am a 'Brit'), are usually a bit strapped for cash & are thus driven to create, (we don't usually copy), extremely elegant, simple, (cheap), and original solutions to technical problems, (for instance, using a silver mesh to safely catalyse conc.H2O2 in monopropellant rocket engines thus removing the need for a liquid catalyst & doubling the amount of H2O2 carried for the same weight.) Secondly, if, hypothetically speaking, we 'Brits' HAD been guilty of such execrable behaviour, surely the Americans would not be so weak-minded as to merely 'ape' that behaviour ? .. As your parents might have taught you .. "Would you also put your hand in the fire if someone else did it first?" .. Oh well ..
@@Mr.Swann. Having worked with someone who worked in France for a number of years, he was surprised to learn of all the nasty stuff the brits have done in the past that the brits don't generally get to hear about.
@@millomweb Ah, yes, indeed. Our gallic 'sparring partners' over the centuries have an expression for that; in English, it is .. "PERFIDEOUS ALBION", (contemporary rendition would, perhaps, read .. "SNEAKY BRITISHNESS"). We've been hurling calumnies at one another for centuries to the point where it has become almost a National Sport. We have both competed for and had 'Empires' .. (to an extent, the French still do, and tend to treat those native to their remaining 'possessions' & 'protectorates' , it must be said, rather poorly.) The relevance of that statement is that most countries who secure independence from a 'Great Power', (not many of those remain, thankfully), run away, cheering, shouting, (bellowing whatever their National Equivalent is of the Confederate 'Rebel Yell' .. which I rather like, by the way), , & firing guns into the air ! .. HOWEVER , there is an 'agreement', 'confederacy', ''trading group of nations', (indeed, rather a mix of all of these), known as the BRITISH COMMONWEALTH. Countries which USED to be part of our 'Empire', but which are now independent, have tended to ASK to be PART of this, and remain so TO THIS DAY !! .. Canada, New Zealand, Kenya, Jamaica, India, (and quite a few others .. gosh, we DID get about a bit in the past, didn't we ?), are all members, and Australia, (who have had a couple of [referenda / referendae / referendums], am unsure of the plural form for 'referendum'), to see if they wish to forget their historical ties with us, but who's population stubbornly keep voting to stay IN this Commonwealth ! To conclude, for them to not actually detest those 'rotten chaps' who USED to 'exploit' their countries, one may, perhaps, wish to conclude that we weren't actually that bad ! .. We're still not ! There is a pragmatic reason for this; England is just one of a group of four countries forming the United Kingdom; three of these countries are on one, fairly small & crowded island. We must trade to survive, (and this has always been the case). To do this we HAVE to be fair and to 'get along' with, well, everyone ! .. (would you buy a car from someone who everyone told you was a crook, or from someone with a reputation for fairness & honesty ?) Hence, finally, you may perhaps, wish to ask your acquaintance who worked in France for verified DETAILS of .. (and I quote .. ), "all the nasty stuff the brits have done in the past that the brits don't generally get to hear about." We can then discuss this further. I enjoy a good debate, and have even been known to concede that I'm absolutely wrong, and to publically apologise .. IF it can be proven to me that I am ! .. (and most 'Brits' are fair, and open to reasoned debate in this way.) Regards, 'Swanny'; (feel free to call me that, if preferred; most of my friends do.)
@@Mr.Swann. Plural referendums, referenda #OED
I guess referendae would be the plural of referenda.
Regarding devolution, why is it that no one discusses where borders should be ? What if Cumbria and Northumbria wanted to be Scottish ? If Cumbria wanted to be - then what about Lancashire ?
What if the only place that didn't want to be Scottish was Westminster ?
Och aye the noo !
A little bit of Clarification at 15:29
The picture of Tessa's 3 phase six wire transmission, is a standard motor found in the market today. The wires ends are labeled U1, V1, W1; U2, V2, W2. Because of this you can make this motor a Delta or Star or other motor, At the time of installation depending how you jump the connections. Some systems change these jumpers while running but it's rare nowadays. When you see one it's a real delight, especially when you see a person see it for the first time.
The picture of M. Von Dolivo is not showing that he made 3phase but that he was working on an Improvement on his Transformer, on the right half of that picture. On the left half of his picture is a 3-phase Delta Dyno that uses slip rings. Motor with slip rings are not used very often anymore but were in the early days to help adjust the resistance of a motor dynamically. This was to help produce better running torque. In the illustration he is not dynamically changing the resistance of the slip rings. But this is something he is given credit for. Vons motor is set up as a delta.
Hi Kathy, As a former electrician who worked in the electricity distribution sector and a person who has an interest in the history of science and engineering, your channel is my new YouTube happy place.
Thanks for the putting in the effort to create interesting and informative videos. No it's back to binge watching the rest of your videos.
I look forward to buying and reading your books when they are published.
As an engineer (retired) I've always been interested in science and technology history. Thanks for bringing to our attention some of the lessor known, but very important contributors to developing the electrical systems of our modern world.
Glad you liked it.
Wow! What a brilliant person and a great speaker. Looking forward to your book. I have been an electrical engineer for 45 years and didn't know the connections Kathy made with the history. How could you not love math, science, and engineering?
Great video! I am an EE and took a power systems course as an undergraduate, but I never appreciated this history. Thank you so much!
Dear Kathy, Thanks so much for your amazing compilation of videos on the history of science. I understand that the amount of research that goes into making these is immense. Keep the great work going!! Glad that I came across your channel.🙏
Thank you so much for your kind words.
One of my buddies in HS in 1964 and I built a 12v DC motor from nails and Cu wire for Science Fair. He went down in Vietnam January 1970 as a helicopter Army Warrant Officer. 58,479 brothers and sisters never made it back. May they rest in peace.
I'm glad to discover your channel! I wanted to understand 3-phase to discuss with my son who does theater lighting. This video helps make sense of electrical distribution and evolution. I liked, subscribed and plan to view more episodes. I love your enthusiasm! Thank you for the research and well organized presentation.
This stunning, enthusiastic and informed woman just blows my mind. Her knowledge and her enthusiasm for explaining things just left me with my jaw dropped in my eyes wide open listening to her. No I want to know more about electricity.
Thank you so much. 😊
Another great video…again! Thank you! I went to grammar school in Lauffen, from where the first 3 Phase long distance power transmission was made and I am happy that you pay so much attention to the meaningful experiment of those brave engineers to transmit huge amounts of power over more than 100km. I can say that much of the electric history is still alive. There still is a water turbine running in the place where they had run it then. There is an ‚Oskar von Miller Street‘ running down to the cement factory. The factory still exists and AEG, the firm Dobrowolski worked for, still exists, as well as Brown‘s firm, former BBC (Brown Boveri Cie), today ABB (Asea Brown Boveri). All of them managed to be enough innovative to make it into the 21st century.
Wow that is so cool.
@@Kathy_Loves_Physics , ASEA claimed to have the first commercial three-phase long distance transfer system up and running by 1893. Perhaps worth looking into how they fit into the grand scheme of things?
This was an outstanding presentation, and had me riveted to the screen for the entire time, which seemed more like 3 minutes than the actual time. I had no idea that the evolution of the electric power design was so complex, with so many players.
Thanks
Wow these stories are always more complicated than one hears. Thanks for telling me about the amazing contributions of Dobrovolsky et al. There's such a lot of Tesla hype ;) Great stuff, subscribed, thanks.
Thank you for the full history. In the US, so much is US-centric, other contributions being brushed off as inconsequential. It's good to know the full history of technological development when trying to understand the technology.
Great history lesson, I was under the impression Tesla was the first the appreciate the theoretical advantage of 3-phase AC and worked with Westinghouse to popularize 3-phase AC in the battle of the currents. I had not realized there was a 2-phase and 3-phase school early on or of Mikhail Dolivo-Dobrovolsky tremendous contribution. You have shown, as usual, the development of practical poly-phase power distribution was much more complex.
I’m so glad you liked it. Frankly I think the majority of us thought that Tesla pushed three phase in the war of the currents, as that is how the story is usually told.
All this misleading facts about Tesla is due to the erroneous social media posts. Now they have created a cult around him.
I have written many time against this blind veneration of Tesla & pointed out the importance of Dolivo- Dobrovolsky.
@@susilgunaratne4267 the populace loves a simple story of a hero to worship. The actual complex and nuanced reality of many people contributing to progress is too difficult to digest. Kathy’s essays are exceptionally good at putting things into the right perspective.
@@pansepot1490 Exactly that's how people turn in for the hero
worshiping to please their mind what ever the reality.
She went to the wrong uni. Ha ha. AC was first discovered by tesla and this is how electricity was spread further and the wholeworld knows about this. The rest is the people were playing with the AC created by tesla however they did not know how to work it out at all ha ha so tesla once again went ahead and did it. Thus he is the founder of ac , and that ac was simply because electricity could now be transported further after that comes all these stories but the people who were trying to further tesla work could not do it ha ha so he did it all.
Haven't watched this video yet as I've just discovered your channel and am slowly working my way through from the beginning. But I couldn't wait to let you know, I absolutely love both your content and style. You make it look easy but I know an awful lot of work goes into each one. Thank you so much for taking the time.
@deaniegarcia5694 - 2023-07-26
I am a retired EE, and never paid much attention to power systems, preferring information and computation,but you make this stuff compelling! I watch your videos often, and it, almost makes me want to go back to work! Keep up the great work!