Physics and History of Why USA uses 120 volts and not 220 volts
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- čas přidán 20. 05. 2024
- Why do 1/3 of the countries in the world use around 110 volts and the other 2/3rds use around 220 volts? I go through the history and the physics to explain why it is so confusing.
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I MADE A MISTAKE: I stated that if you add more light bulbs in parallel the bulbs will be dimmer because the resistance will go up. The light bulbs *will* be dimmer if more are added in parallel but not because the total resistance increases. In fact, the total resistance will decrease as they are in parallel. The bulbs are dimmer because more current is being drained from the generator and the internal resistance means that the *voltage* over the individual bulbs will decrease.
I am so sorry, I should have realized what was happening with a bit of thought. Also, now that it is up, I cannot edit my video (although I did add a little card in the corner).
Also, many of you were confused by my quick transition between Edison's 3-wire DC and Westinghouse's and European AC systems. I should have been more clear about when that transition happened, sorry.
No problem this is second nature to myself I wish you would have clarified earlier about Edison starting out with direct current
Ha, ha!!! I was about to point out that you had the relative resistances backwards but you realized it first.
Caught that right away, was about to stop watching thinking this chick is way over head, but you proved me wrong. Bottom line, it's all about the wire thickness. For a given amount of power used, the higher the voltage, the thinner the conductor. Also the rest of the world uses more aluminum wiring, less expensive than copper, but lesser ampacity. All this talk about AC electrical transmission, and no mention of Tesla?
@@ronalddaub7965 Edison and his DC is fairly common knowledge. Where have you been, Ronny?
Is that what we now call a 'brown-out'
Also, why does the UK have a fuse in their plugs when the US does not?
32 years in power transmission and still so much to learn.
People like you make CZcams awesome.
Thank You.
Thanks 😊
I love your enthusiasm, but showing photos & graphs then throwing your bare white contrasting hands around makes the transition from one to the other less than palatable. Thanks 🙏🙂Maybe wearing darker apparel would be all that’s needed. This is wonderful show!
Please Dont Curb Your Enthusiasm! ❤
@@barrywhite9114Kathy has explained that she was diagnosed with ADHD and that moving her hands is, for her!, a necessity to be able to think.
I recommend to watch that video.
_"People like you make CZcams awesome."_
There are so many people, like her, that make CZcams awesome that I prefer CZcams videos to TV shows. I'm not only entertained, I'm also informed.👍
-Thanks for your hard work and research on this. The reason the Chicago Exposition was such a triumph for Westinghouse has to do with Edison refusing to sell lightbulbs to a competitor. That wonderful genius Nikola Tesla took a look at the problem, and invented fluorescent bulbs, which cut Edison out of the picture completely. That pretty much was the reason the "War of the Currents" came to an end, as AC could be distributed over thousands of miles, whereas DC was very much local-distance only. Edison gets far too much credit, and Tesla far too little.
I have to agree with you, that Nicola Tesla formed the basics of the AC Power Grid, but Edison took all of the accolade. Tesla died virtually penniless.
And now it is starting to swing back the other way with HVDC being used.
Tesla didn't invent light bulbs. She has videos on their invention. She has one on the War of the Currents too.
She has several Tesla videos too. Check them out!
Edmund Germer was a German inventor, recognized as the father of the fluorescent lamp.
I am a data com engineer. I am not an electrical engineer. I remember the fun (lol) of trying to calculate the energy requirements for data center PDU's which had 3 phase incoming, feeding both 48v dc networking gear + 1000+ servers @ 110v ac + sufficient battery capacity in AMP/hours + generator requirements beyond that, etc, etc, etc. I had to attend 2 weeks of classes with APC to learn some of what you explained in a few minutes.
You do an excellent job of explaining things in an understandable manner. Kudos!
Over 1,000 servers? You could just replace it with 1 mainframe the size of a refrigerator, which can virtualise over 4,000 "servers"
1 machine v. 4,0000 the choice is clear
@@rty1955so you want him to use current tech 20 years before it was created. Also you hav3 no idea what a mainframe is, lol.
@@donut3946I worked on 'Mainframes' in the 70's. No such thing as a Server then.
Virtual systems run on Servers not mainframes.
@@rty1955 No problem he'll just time travel and get that done based on your suggestion.
@@rty1955rest of comment not showing
Love the enthusiasm and details covered. The cohesiveness held me all the way through and I can't wait to see the next one. Well done.
When in EE school I got some of the history shown here but it was new to me about the series DC generator/ 3 wire practice. I have worked in steel mills where it was not unusual to encounter motors from the 1910s and MCCs built in the 1920s. The control distribution of the DC to cranes was especially interesting. At 4.00 minutes the diagram reminded of a simple thing we did to monitor the Crane 240Vdc supply. We used 3 240V light bulbs, 1 wired leg to leg and the other 2 from rail to ground. Any fault resulted in a change in brightness to tell us to go find the fault. Working with technology from 1920s and up was a fun challenge. BTW some cranes still used control panels made in the 20s as late as 2010. The same crame had some mechanical parts that had patent numbers fron the 1890s. It was an adventure!
Fascinating! What I loved most about this video is that I got a bunch of interesting questions answered, which I didn't know had. Also excellent narration.
Your video was highly informative. I was not expecting so much information. Very well done. 😊
The other weird thing about Japan (well, the other weird thing about their power grid) is that half of it is 50Hz and half is 60Hz, because two different cities started electrification projects around the same time, one using American-built generators and the other using European equipment.
So which city use 50Hz and which city use 60Hz? Thanks.
I can't even imagine how this can work. There is effectively two different grids, then, right?
@@oscarn-The grids were linked using rotary frequency converters originally. Nowadays they use HVDC links to share power.
@@rickykngoall of Kanto, Tohoku and Hokkaido use 50hz. And all of Kansai, Chugoku, Shikoku, and Kyushu-Okinawa use 60hz.
The Chubu region is split, where all of Yamanashi is 50hz, and all of Aichi, Gifu, Fukui, Ishikawa, and Toyama are 60hz. The prefectures of Shizuoka, Nagano and Niigata are where you can find both 50 and 60hz depending on the municipality. Where Shizuoka and Nagano are mostly 60hz, and Niigata is mostly 50hz.
This is truly weird and probably would've spurred that HVDC transmission projects.
Necessity is Mother of Invention and the rest is history!
As a former electrician, I've known the how of these things but I've never known the why they came to be so I absolutely loved this.
Me the same. Good work from her.
Me too.
If you are an educatated electricition,you should know that 220 volts is better!
Have you any experience at all?
Please do some research on electrical distribution as it is why we have what we have. Also, check upon what 2 phase ac consists of. Just because one system identifies 2 phase conductors does not make the service 2 phase. 240/120vac single phase as provided as residential services occurs in almost all homes in the US. 2 phase distribution consists of 5 wires. Alternators are used for ac distribution. Generators are strictly dc.
Thank You for bringing such fascinating informative information too all of us! ❤
Very interesting Kathy. Thanks so much! Your enthusiasm makes your videos entertaining.
Such a great educator you are Kathy! As an electronics
guy, you have taught me what tech school didn't. Such as the "why" of electrical inventions.
Nice explanation!
Skyscrapers also needed power for elevator motors, without which there would have been no market for buildings over 3 or 4 stories. The side story of Otis Elevator and particularly of Otis's initial emergency brake system (which was little more than a carriage leaf-spring) is fascinating, and he too presented his invention at the Worlds Fair. I read once that with dozens watching, he would stand in his demo elevator and with a chop of his axe, he would cut the rope holding up his elevator car. Instead of crashing to the ground, which was VERY common in those days, Otis's demo car would only fall a couple feet before that leaf spring would open up, lock into the shaft structure itself and stop the car, he sold beaucoup elevators and cemented his legacy in history.
And separately from that, plumbing eventually DID make it to downtown buildings, not only to provide water for the humans to drink or to flush with in the buildings, but also to provide water for firefighting purposes; probably something that Chicagoans were super in favor of after The Great Fire. Even today, we still use gravity and the "column of water" method to provide steady pressure and flow to every faucet, tap, or toilet in a building or area, and the best way to do that is to use electrical pumps to push the water up into a water tower for supplying a wide area, or up a building for storage in one or more tanks on the roof for supplying that building. It would certainly be preferable to have running water (even if it's not heated!) than it would be to carry a nearly 43-pound 5 gallon bucket up the stairs to your office desk or factory station every morning for your day's expected water needs!
Electricity was for so much more than mere lighting. So as Paul Harvey used to say, "...and THAT is the rest of the story".
Thank you!
You don’t need electric power for lifts. Hydraulic power works perfectly well (and was standard in most European cities until the 1940’s).
Hydraulic power lines were more vulnerable to bomb damage however.
The old high pressure water mains were repurposed in the 1980’s for telecommunications conduit.
Early elevators used steam engines for the propulsion power.@@allangibson8494
Thanks for the extra reading! It must have been fascinating to watch the live elevator emergency demos.
@@allangibson8494 Only if you have short elevators, taller buildings would require that the piston be potentially hundreds of feet below the bottom of the elevator. The freight elevator of one of the local buildings has a shaft of roughly 900 feet, meaning that the piston would need to be at least that long and buried to that extent. And the other elevators would need to have shafts of closer to 400 feet going through many floors.
AFAICT, around here somewhere around 4-5 floors is where it starts to become a bit more of a toss up as to which technology to use.
This video was great! I hope your other videos are as great as this one, because I've just subscribed to the channel!
And I loved your endcard as well! 😁
Thanks for posting Kathy. Great explanation.
Fantastic video, Kathy! I really appreciate the amount of time and research you put in your work. It's always worth waiting for you, so I'll always like the video before even watching it! :D
wish you all the best!
Thanks so much Ruan. Will try to be better about posting more often but sometimes it takes me a while.
Always great to have a new presentation. Learned a lot. Thanks.
You’re welcome
Wow, I didn't expect this to go that technical into electricity. Well done.
Great Explanation. I truly enjoy your videos.
Kathy, I am glad to have discovered your channel! Except for the audio quality, this was an excellent video, interesting AND informative! You have a new subscriber!
Yes great content, well shot and lit but the very live sounding room plus just using the camera microphone makes the dialogue a bit too reverberant. A good upgrade would be to plug in a clip-on lapel mic.
Amazing description of all of how this all works! I knew about Tesla(Westinghouse) and Edison. Describing the reason for the country's uses of the different types of power that are used was amazing. I didn't know that it was more expensive for America to use 110, LOL! And now I know the reason why we stayed that way too! Thank you for such a great answer to such an interesting question!
Greetings dear Kathy! I stumbled on your video and enjoyed your presentation! It's nice to see such a lovely person sharing good history! Tho it's old news too me, yet it's been a pleasure to watch your presentation! Keep up the good work!
Great content by Kathy.. Thanks to youtube for suggesting me your channel. Keep doing great work. :)
One suggestion you can show some important words/dates/milestone flowing on screen when you are on video, that would make this more interesting and catchy and this will go to larger audience.
You make an amazing number of factual connections in your videos and you’re engaging. Please keep em coming. Subscribed! Please don’t be afraid to show equations (even if you don’t dig too deep into them). I think you have a lot of folks watching that would appreciate it.
Very interesting with lots of history. I spent 50 years in electrical / electronic engineering and I've learnt new things watching this video! Thanks a lot, Colin UK
Like DC has a neutral and can be stepped down? I learned that today too
Your video was great and specially your enthusiasm made it great
Thank you for that awesome explanation! I'm still pretty confused about all of the details but I learned some new things.
I would love to take a whole semester course of STEM History from you, Professor Kathy. So fascinating and you have an excellent delivery.
@@xyz_zyx "Pesky?"
Wow... I thought this was 2022.
🤣🤣
Great job as always. I remember my brother trying to explain some of this to me years ago and my eyes glazed over and I passed out. You actually made it interesting!
I am simultaneously pleased that you liked it and sorry for your brother :)
While it is nice you got it now as this is a pretty good video.. it is not a "feature" to get bored with knowledge.
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You start out talking about Edison's dynamo as DC, which is true. The system that we use today is AC. You even talked about the transformer with regard to Edison's system. It is physically impossible to have a DC transformer. That is one of the reasons that AC became preferred, it was impossible to transmit power over great distances as the voltage dropped quickly over the lines. Edison's plan was to put a generator on every block.
Love ur enthusiasm!! Great video
Very Good video, perfectly presented, and making the highly technical/scientifical matter very clear to a layman as myself-Bravo
Great work, Kathy. Having taken electrical wiring training many years ago, I learned something new about the origin of 110/220 volt circuits.
Your Kitchen Range uses 240V, Dryer 240V, Water Heater 240V Air conditioner 240V unless you use gas and prop windows open you do have 120 and 240 in the USA and have for many years. OHMs LAW can explain this all very well.
@@chrisowen2925 Ohms law does NOT explain it. In fact it is NOTHING to do with it.
It is to do with the voltage across the windings of coils on the secondary side of the transformer.
It's to do with the formula for the voltage output of the transformer which is:
Vout = Vin.(N2/N1)
Where N2 is the number of turns on the secondary side, and N1 is the number of turns on the primary side.
It is also to do with Faraday's law of electromagnetic induction and mutual inductance.
Nothing there about Ohms law whatsoever.
@@deang5622 And you trolled me again.
@@deang5622 - Ohms Law does have some effect, note that the AC Power is rated at 120 v & 240 v, however when you look at motor nameplates most at rated at 115v & 230 v. The reason is voltage drop which can be calculated using Ohms law for AC RMS voltage/current. The reason for the 5 v difference is that AC motor companies allow for a 5% drop in line voltage due to wiring resistance and transformer winding resistance.
What an excellent explanation! We are waiting for your next video to know about 60 VS 50 hz
I love your enthusiasm Kathy, I've often wondered about this. Could you look at the development of underground transmission lines, and the move towards DC for long distance transmission?
Another awesome video! I love your work & teaching method.
Hello and thanks for this video. In Belgium, they went from 110 to 220 in the early 1950's. That's why old folks had huge auto-transformers at home if they wanted to use their old equipment.
Worth it, 230V is so much better
@@m0r73n It happened in my city in the late 1970s, and the transition was quite smooth. Autotransformers were a no-no (and still are), we used "real" transformers with insulated windings. I don't think that the difference between 127V and 220V mattered much then. Residential consumption was very low, we did not have today's high-current toys like 10KW electric ovens and 20KW water heaters. My parents' apartment had a 20A (2.5 KW at 127V) input breaker and it never tripped.
At my family houses, it last a decade before buying equipment that worked on 220V, I'm from 66 and I remember these small transformers in use.
@@jmi5969 Also 120V has a lower potential energy than 240V resulting in a lower risk of fatality and allowing for smaller and more space-efficient plugs.
@@davidperry4013 One other issue is arcing behaviour: the "american" 100-120V series arc is less persistent and ultimately less dangerous than the "european" arc. A collateral, probably unexpected, is that the European arc fault detetection devices are somewhat simpler and less prone to false positives than the American AFDDs.
As for the size of power plugs - is there any need to make them smaller? our hands remain the same, and old folks likes yours truly aren't that good in handling small things.
I enjoy your discussions on the history of electricity. My dad, like me was also an electrical engineer, said that in the early days of development of the light bulb, it was difficult to make the filiment thin enough for a higher resistance to run on 100 volts. The tungsten filiments were coiled to keep them compact so they didn’t have to have wire supports in the lightbulb. The 220v made the light bulb more difficult to make. Years later by better manufacturing techniques, they were able to make thin high resistance filiments. The 7watt candelabra light has a really fine filiment that was fragile and it took even longer to develop. When I grew up in the 1950s, when decorating Christmas trees with these bulbs the filiments would break easily when dropped.
Remember that the only use for electricity in the early days was for light bulbs, so making practical filiments was important.with time light bulbs got smaller, but they were then made for lower voltages and ran In series.
PS I worked in two Silicon Valley laboratories where they developed the first practical LEDs in the late 1960s, that is Fairchild semiconductor and HP laboratories. HP first used them in the HP-35 calculator. “You could get them in any color as long as they were Red”! To paraphrase Henry Ford. Ross
She has videos on the development of light bulbs.
😂you could get them in any color as long as they were red.
I had a HP-33 in 1978 with red LED’s.
@@ursus9104 I also had an HP-33 many yrs ago.
Maybe you should visit Cragside one day (the first house in the world to be lit by electric light) to disabuse you of the notion that it was only for lighting.
thank you for your content!love you❤
Today you electrified my day with your informative electricity history ❤
At 2:35, the correlation between loading and resistance is backwards. The more loads you have in parallel, the LESS resistance you have, not more. The reason why the "popular" lines weren't as bright is due to a higher voltage drop across the conductor. More current means higher I^2R losses.
I think she just meant that there were more resistive loss in the wires when said wires supplied more loads.
Yes, I was unclear what she meant. If more loads are turned on then, from the point of view of the generator output terminals looking towards the loads, the system load resistance is reducing not increasing. As you say the losses in the distribution conductors will increase because the reduced load resistance causes more current to be drawn assuming a fixed generator output voltage . Hence I^2 R losses have increased and load resistance decreased.
I did enjoy the video and learned why USA uses 110 and 220,🙂
@Patrick Ray You're absolutely correct. I was about to make the same comment and started by checking whether anyone else made it already. Another reason the "popular" lines were not as bright was voltage loss within the power source (in addition to the voltage loss you mentioned in the wires).
I agree Kathy has confused the correlation between resistance and load/demand current flow in a parallel circuit as illustrated. The more light bulbs on at the same time are going to reduce resistance in the circuit and allow more current to pass/require more current without exceeding the ability of the generator or a voltage drop would occur, dimming lights. Voltage drop being a symptom of insufficient generation or resistance between the generator and load.
I don't know a lot about the Edison system [why I am watching this] but it seems it was a DC system rather than an AC system and I wonder if it also a series circuit system rather than a parallel? That would explain increasing resistance as more lights/load was added.
09:00 Oriel Chambers, Liverpool, built in 1864 is regarded as the first steel framed building in the world, and the design principles were brought back to Chicago by architect John Wellborn Root who was studying in Liverpool as a teenager, during the time of its construction.
There was the Shrewsbury Flaxmill building built by Charles Bage back in 1797. Cast iron, rather than steel but served the same purpose of being A) fireproof and B) offering maximal interior floor area for the industrial machines. It still stands, worth a visit.
The shrewsbury flax mill in Shropshire UK built in 1797 was the first metal framed building in the world.
Scotland and England were very creative in the uses of cast iron and steel.
Thank you for SHARING your knowledge
It was very interesting for me as an electrician to learn some historic background and some facts I never heard before. Thank You very much
What is not commonly known is that Germany used to have a 115V+115V AC system when the Schuko plug was first developed although there was never a 115V + neutral version. It is why, to this day, in those countries where the Schuko plug is standard, like Germany and the Netherlands, domestic outlets are not polarised. Whilst there is a neutral + live(hot/line), it's completely random which pin is which when plugged in (which isn't a great mix with Edison screw light fittings as there's a 50:50 chance which way a table lamp will be plugged in (and it also means that there's a 50:50 chance than any single pole switch will be on the neutral).
These days it's different in Germany and the Netherlands where they tend to supply domestic properties with three phase and tap off individual single phases at 230V for circuits (although more powerful appliances, like ovens, will often have more than one phase connected).
Such is the way with legacy systems (of course North America didn't used to have polarised receptacles either; that was introduced later by widening the neutral blade).
This reminds me when living in West Germany in 1955, ("Army Brat"- Dad was assigned there.) the German house we occupied had 110 (115?) volts electrical service. That meant we could use our U.S. made appliances without requiring the use of step-down transformers. This just required Schuko to Edison socket adapters.
Then, one day, teams of electricians (lineman) rewired the village of Bad-Windsheim for the then-standard of 220 volts. Dad was prepared with two step-down transformers and 220V light bulbs... We arrived home later in the evening and my brother and I had fun, running ahead of my father and turning on the lamps in each room and thrilling at such bright lighting for a few seconds.
Very interesting! Same goes for The Netherlands, except here it wasn't 110+110V but 3x220V resulting in 127V to ground from either pole.
Steve Jones I’ve always wondered why it was the neutral blade of the plug that widened instead of the hot? Is there more potential for heat on the neutral? Is that why it was decided to make that blade larger rather than the load blade?
@@deanbortz7747 Personally I've no idea. the current should be identical on both (or GFCIs would not work). In every other system I know of with polarised connections, such as those in Australia/NZ and the UK, the neutral and hot/line pins are exactly the same size. It's the shape of the plug that then ensures polarisation. In the case of UK plugs, they all have three pins and only go in one way. With the Australian system, the pins are angled so a two pin plug (as well as a three pin one) will only go in one way.
As the addition of polarisation to the North American system was a retro-fit, then they had to maintain compatibility with earlier plugs and that was done by just making the neutral blade wider. I guess it could have been either.
As a side note, the Australian plug design is the work of the same man as the classic North American plug, one Harvey Hubbell. What was later adopted as the Australian plug was designed and patented by him in 1916. He had intended that it replace his earlier plug (which he'd designed in 1912) as an improvement, but it never caught on. As is often the case, compatibility mattered more than functional improvements. Thus the Australians, who were later to electrification, standardised on that plug layout in 1917, reputedly because it was easier to manufacture in Australia than the British round pin plug which required solid brass pins rather than flat blades (the old British round pin standard is still in use in some countries, like South Africa and India).
@@TheEulerID In UK the Earth is connected to the "can" or "chassis". When I moved to Hanau from Norwich I was always careful how I plugged in my soldering iron. One day I forgot to take care and "soldered" 220v into my TV while repairing. The Eeprom "window" had black specks under it. ..... I will have to bike-ride that Lauffen-Frankfurt "3ph Trasse". I am 68. Cheers.
Wow, Kathy, this was extremely informative on so many different levels. You touched on it, kind of, but even with 220, we are still 110! It’s just that the other leg is inverted to the main leg so that they sum to 220.
The other leg is not inverted, it's the same as the first leg. There is no second phase.
@@xiaodingjones1554 I was looking for someone to correct her about phase separation angle and adding phases. Single phase with center tapped secondary ground/neutral. The legs Y-me referring to are these opposite sides of a single phase.
@@xiaodingjones1554 In the US we have split phase, so the phase of the two legs are 180 degrees apart (technically in relation to neutral, but that gets a little more complicated to explain)…
I really love all your videos on electricity and dynamos and generators etc.
Well explained! Thank u so much! ❤❤❤
We use BOTH voltages in our US homes. All my heavy equipment uses 220 such as cooker hob, oven, A/C condenser unit, pool pump motors and clothes dryer. All regular light duty stuff is 120 which is more than enough for lighting, kitchen small appliances, tv, computers etc. I think our electrical system makes complete sense. Yes, we have electric kettles and toasters running happily on 120 too.
I recall from 1975 when we first came to the US that my wife wanted to use her UK sewing machine so I wired up a connection to the cooktop 240 volt for her and she was able to get sewing.
Yeah but most other countries at least in eu use 230v and if you have heavy use you can get a 3phse where you can get triple the power
You are correct. Most homes have at least 220v coming to them in the US. The neutral conductor allows us to ‘split’ that voltage into 2 110v legs. While 110v is less efficient, it’s physically safer to the user. There’s is a heck of a difference if you get shocked with 110 vs 220.
@@yolowolfyt 3 phase and a myriad of voltages is available in the US too in heavy use area.
@@yolowolfyt no home needs three phase. Larger users such as public institutions, offices and factories all use three phase. Even my church uses three phase. Three phase power lines run through every neighborhood. If your small farm needs three phase for certain new equipment you can have it wired in. It’s just a matter of having an appropriate voltage for the need. I am happy to have a safer voltage of 120 for all normal outlets. With the advent of led lighting, flat screen TVs and small appliances the wattage needed goes way down anyway.
If you're in the US, you haven't used 220V power since the 60s. The US residential grid today is nominally 240V.
I am very impressed at how you can gain all this history and just explain it to us with reading it all from cards! You love this history and it show. Thank you for the wonderful history lesion's and facts of our heritage here in the US.
Such a fun but highly informative video. Thank you !
Just a tip but you need a body mic (or a better recording location) to reduce the harsh echo of the room and better lighting (you're being lit from below). You tube has videos to fix these issues. Cheap things like moving blankets hung while recording will soften the sound and lighting. Great video and topic. ❤
Interesting set of historical facts!
When comparing 3ph and 1ph and 1ph/2legs (now called "split-phase") there are quite a few differences in how those are connected and work. For example in the Delta configuration there is no ground wire. You can get 120VAC on one node, 208VAC on two nodes, and 480VAC on all three. In the Wye configuration you do have a ground wire (so four wires instead of three) and that allows more redundancy if a phase failure occurs.
Your typical 220-240VAC residential circuit used to be called "2 legs" not "2 phases" because the two hot lines were two circuits providing the same phase BUT opposite voltages. Now it's called "split phase" because --as you correctly point out-- if you call it like you see it, each of the hot lines is 180° out of phase with the other. The disadvantages to this is that there exist periods of 0VAC (every 1/60th of a second on 60Hz systems) whereas if offset by a real phase difference there would never be a 0VAC spot, but there would also never be a 2x1ph VAC spot either. Motors (HVAC equipment, pumps, etc.) like this more. However, water heaters and incandescent light bulbs don't like the 0s mixed in with the 240s. (And yes, there are plenty of 208, 277, and 480VAC incandescent lights... mostly industrial and businesses in the US.)
Transformers are not cheap, so one of the compromises is what voltage to run to a residential neighborhood to save money on transformers. A 4KV-->240V transformer is much cheaper than a 14KV or 40KV downconverter.
Things like compressors like 0VAC points (they are motors, after all) but things like welders don't. All of these are compromises. The reason for the compromise is the desire to run higher voltages to reduce amperage thereby allowing higher gauge wire (thinner) with a lower ampacity but saving money on copper or steel (must use even more steel for same ampacity).
And finally, there are power-factor correction devices (think "huge capacitor banks") that store the energy during non-0VAC points and release it at 0VAC points to make for a constant voltage. This turns horrible-PF devices like HVACs from 0.2-0.3 to near 1.0. Electric Utility companies in the US like businesses to have a PF close to 1.0 an reward businesses with much better pricing (because they size for average use, not peak) and that often covers the cost [over time] of the PF correction device. These are more often seen in the 480VAC and higher world.
Best wishes
I was just reading about power factor a few days ago, prompted when looking at the schematic for my Miller welder. It showed an PCF option so I delved into it. It was I think 4 x 200MFD run capacitors. There was a chart showing the amperage difference with and without. If I as welding all day I would be very interested as it indicated a fair reduction in power used.
that was one of the most informative and well written explanations of electrical power distribution in america as it is done today that I have ever seen. I'm a retired electronics tech and learned a couple of things and relearned a couple more that I had forgotten, thanks for the refresher course. :)
Power (kw) used by your welder is the same; just amperage in the lines feeding the welder is lower with pf correction. PF correction caps put voltage and current closer in phase. When 100% in phase, pf = 1. PF correction in residential systems is usually not an issue because you are not billed or penalized for power factors less than 1. With better pf, you may be able to get by with smaller gauge wiring, ie, if your welder is a long way from your service panel, but your electric bill is not likely to change. However, industry uses considerable energy, and pf less than 1 causes higher line losses for the power company. Power company will bill industry at higher rates for poor pf to cover these losses.@@stephensarkany3577
230 Volt 50 Hz down here in New Zealand, So glad you just didn't talk about what happens in the USA as your audience is international. You Rock !!
thank you,for posting, Ma'am.
I wish my electrical apprenticeship class had this video available on the first class night. It’s a great preview of what you are going to learn. Thanks for the historical perspective.
Fantastic presentation of some important power history. I'm a retired EE/CS and while very well read on early AC power as well as some on Edison's DC, the use of +/-110 V by Edison as a means of copper savings was not known to me. Impressive research, and a most enjoyable presentation.
I'm looking forward to your book and thank you for your outstanding work. One piece of history I'd love to see you do is Edison's early attempt to use earth as neutral, and the resulting shocking from step voltage potential. Another would be the insane WYE multiple earth grounding practice which was used to protect motors, but violates transformer isolation and thus injects massive neutral current through the earth as well as creating a problem similar to but lower than Edison's earth as neutral.. Zipse's work is a good starting point.
Thanks again for all your outstanding presentations. I'm a big fan.
Bruce
Glad you liked it Bruce and am interested in what you think about my next video on 3 phase
Edison was the crooked businessman; Tesla was the true inventor.
@@foureyedchick life is a bit more complicated, both Tesla and Edison did things that today we would consider dishonest and Edison did invent stuff quite a bit
@@foureyedchick whoa, you should change your name to Racistgirl. Your entire comment is both ignorant and uncalled for.
@@brianm1916 And what are YOU? A meddler in somebody else's conversation? What are you? His lawyer? His gay lover? What should your name be changed to? "Brian M --> Brian Misogynist"
Thank you for your great job. There is one mistake around 2:30. More lamps will make less resistance instead of more. And more current will drop the supply voltage and therefore dim the light.
I am so sorry that I had such a brain fart on that one, of course that’s why more lightbulbs in parallel will be dimmer. Thanks for correcting me so politely.
@@Kathy_Loves_Physics I just want to let you know that your audience did pay attention. We learn a lot from you. Thank you.
Yes - I caught that error as well. "Zoe the Robot"
Best layman's description I have ever seen tinged with both history and great storytelling.
SO thankfull for your video about an issue that baffled me for years!
An impressive depth of knowledge, thank you for all of your presentations.
I've watched a few of your videos and I'm impressed at the effort you've put into it as well as your research and delivery. Very interesting videos thank you. PS, please get a lapel mic, your audio quality will improve dramatically and you won't have to yell :)
Or get a Shure SM7B the daddy of youtube/vocal mics!
Yes, please, and give the room some acoustic treatment. I found your channel tonight. The echoes were painful.
Thank you for the Knowledge and interesting presentation.
I enjoy listening to your video and very informative, Knowledge is not easily obtained. Thankyou
A good presentation concerning the history of modern electrification of the US and world I would like add the following.
December of 1887, Tesla filed for seven U.S. patents in the field of polyphase AC motors and power transmission.
These comprised a complete system of generators, transformers, transmission lines, motors and lighting the German
system is based on Tesla's alternating current system which went on to illuminated 1893 World's Columbian Exposition
in Chicago.
Ha! Kathy has a vid out on just that(3 phase electrickery). Its really good too.
glad you brought that up, no one remembers that edison held back the country from going electric because he fought tesla tooth and nail because he is a fucking egomaniac and could not accept the truth and the real genius behind modern elictrical power, i blame edison for tesla dying broke
@@jimmieroan9881 - I think Tesla broke himself with his fixation on Tesla coils and wireless energy transmission. He built the hugely expensive Colorado Springs lab shot lightning bolts around but never created any marketable products from it. The Wardencliffe Tower on Long Island was the final straw and even his most ardent investors had to say no, we are going to build a system to send electricity through the air for free. Great creative thinker and inventor but no practical engineering and economic sense.
It an't modern ,it's shambolic.
Great job. At 12:35 into the explanation about home electric dryer powering, there are not two phases here. There is only one pole transformer and only one phase of the 10 KV high-voltage tap. It is true that, in reference to the center tap, the two 120 volt ends are 180 degrees out of phase, yet still the dryer works on a single phase. It is not a 3-phase dryer.
This is correct
Still single phase at 240v
Yep. That is why a point is made to call that split phase. As in being a split phase of a single phase. Or a single phase being split by transformer tap.
Keep keep that channel coming thank you 🙂
Thank you for the informative video!
I love these videos! Kathy is the only presenter that gives both technical and historical information. As shown in her videos, politics and human interactions produce not only significant results, or they ruin things for years. Gee, I thought scientists were only interested in the truth.
Love your enthusiasm and history lessons. School would of been so much more interesting with a teacher like you. Thanks.
Awsome information, thanks Kathhy.
Thank you Kathy. After years of studying the latest code books, and wiring residential houses for many people, I really enjoyed your presentation for it's simple clarity and history. This explanation really helps me understand the why and how of electricity is based on historical needs and development. Do you have more on this subject of the physics of electricity that explains the size of wires, loss of energy in transmission, the measurements of voltage, watts, and electronics? Fascinating subject!
Your article on a new design of incandescent lightbulb (G2, 13 January) perpetuates the common myth that the original was invented by Thomas Edison. While a number of people were working on this at the time, it was the British scientist Joseph Swan who demonstrated the first viable incandescent electric bulb in 1878, some 18 months before Edison did. Edison, however, had the perspicacity to file his patents before Swan (and before he’d produced a working example).
Dr Ian West
Jackfield, Shropshire
And yet multiple court cases filed in US courts trying to break Edison's patent for the light bulb due to prior art all failed at the time for lack of evidence.
Edison has been regarded by many as a thief.
Great video! Interesting info about filaments. One correction is that we do use 220V in the USA, it's just split at the home into 2 110V legs, just like the light bulb diagrams you presented. 220V is brought into every USA home from the pole.
220 v is phase to phase voltage, and 110 v is phase to neutral. From the pole the single household picks phase to neutral, while relatively large customers pick 3 phase and neutral, thus they have options: utilise 220 or 110 volts. 3 phase motors consume 220 volts - 3 phases without neutral, home appliances- phase and neutral 110 v. The 3 phase is essential when rotating magnetic field should be established in electric motors without commutator brushes.
@@khatokhato9350 It's 380 V in Europe for 3 phases. Again, outdated infrastructure.
@@lepton555 Noting that the 230V AC nominal is phase to phase from the 3 phase and not phase to neutral. In the UK and Ireland (which are all decidedly in Europe despite Brexit) at least the three phase is 415V. I am not sure you can even get 220V from 380V three phase.
That is exactly what we do in Trinidad and Tobago we use 110 v however 220 v can be connected from the panel with the 2 110v I currently have 1 220v plug for my washing machine and my welding plan
@@winstonseecharan6321 that right, but Kathy she said u s a used only 120v, look 120x 2= 240v 6321 u understand this I a greed with U 👍👍✋.
Thank you so much for educating us.
Just discovered your interesting and informative site. Thanks!
Hi from 240v UK... We had a novel experience a few months ago. A fault in the electricity 11kv distribution, left us with just 70 volts. However all our LED lights were just as bright at that voltage. Our 2Kw cooker elements would not heat up at that voltage.
many led lamps incorporate a constant current supply or regulator, dropping the line voltage (within design limits) will still result in same current delivered to the LEDs
Also from the UK but didn't know about this, what part of the country did it happen in exactly?
Hi @@Admiral_Jezza It happened on the outskirts of the Wrexham Industrial Estate. I am still trying to work out why we went to 70v, and not zero. Maybe the 11Kv line only had a short on one of the phases. The arcing lit up the sky for several minutes, even though we were 5 miles away.
In the past 130V incandescent lamps were available for rural areas where the voltage was not that well regulated. An incandescent lamp burns out exponentially faster as the voltage increases and the higher voltage lamps would have a much longer life.
Another trick before LEDs became popular was to use 28V lamps as indicators in 24V circuits. The indicator would not be as bright, but the lamp would last substantially longer.
They actually had invented light bulbs that would never blow do the manufacturers got together to make it compulsory for to have a set life time in hours for incandescent light bulbs ,the word for it now is opalescence
@@noelburke6224 While there is actually a word opalescence (meaning roughly glittering multi-colored) you probably meant planned obsolescence.
There was never a light bulb which never blowed. However, in building a light bulb you have to find a compromise between efficiency (hotter is better) and live time (cooler is better). In order not to burden the customers with decision, the light bulb producers DID have a secret agreement on the bulb life time. Purely coincidentally, that did not harm profits.
130 volt bulbs are sold now as “long life” bulbs. Ordinary incandescent bulbs are now outlawed in the USA but specialty bulbs are still legal.
When I was a kid, LEDs were still new. A lot of kits and tutorials still featured 4.5V bulbs for 3V circuits. They worked as indicators.
@Andy Peek It's funny but torch bulbs are the other way around - running a 1V bulb off a 1.5V cell. (Commonly a 2.5V bulb off 2 1.5V cells.)
Interesting compilation of engineering history. Thanks for posting.
Very informative! Thank-you!
You’re content is interesting, motivating, and always brightens up my day even if it’s already great. Thank you!
Very interesting lecture!
In Dutch we have a name for this phenomenon: De wet van de remmende voorsprong, the Law of inhibiting head starts. Those who implement something first do not get to incorporate later improvements that are incompatible with the earlier version.
Jump in first and commit to a new technology - you get the “less developed” form of that new technology
English needs a punchy phrase like that for this phenomenon. It is not quite the same as "technological lockin", which locks the whole world into (sometimes inferior) technology choices. Both are common.
120v going from to 230v is not a step up in technology. If you wire a broadcast tower for lighting in the pre-strobe days the FAA required that beacons on the tower consist of two 620 watt incandescent lamps. If your tower was tall enough you may need four or five beacons. In my now remote youth I asked my supervisor why are these lamps 120v lamps used on the tower instead of 240v lamps. He said "240v lamps only have half the expected service life." Europeans spent their money on tungsten rather than copper. Besides you don't want to do this any more than is necessary:czcams.com/video/f1BgzIZRfT8/video.html
Not that I ever did.
First time listener and I loved it. Good work.
Thank you for that fun history lesson.
So much to learn…
My house built in 1910 originally only had 4 circuits at 110v. I always wondered if it was missing a “leg” for not having 220. Thank you for the video explaining that it was normal to only have one hot and neutral at the time for residential buildings!
I lived in a house (Pittsburgh,PA,USA) that only had 4 110v (fused) circuits in the 1990s! My dryer, furnace and water heater were all gas, luckily. But doing something "crazy" like using the Microwave and say, the toaster or coffee maker at the same time weren't gonna work!
120V 60 Hz 30 Amp and a four fuse electric box, two wires leading to the mains, not today's 3
It's not normal to have multi-phase in British homes, but we have plugs with freaking massive pins for carrying 13 Amps, and that at 240 Volts. (3kW from any socket!) They were supposedly invented for our tea kettles. Full-size cookers have to be wired in, but we can just plug in anything else; I've never heard of a gas dryer before. ;) Even some heating can be done with plug-in devices, but sadly, standards have slipped to the point where the fire department recommends you never use more than 2/3 of the available power from a socket.
@@eekee6034 Lots of people in Pittsburgh have gas appliances as this area is sort of a "Saudi Arabia" of Natural gas. It's cheaper to use gas than electricity for anything that "heats" for this reason. Of course gas dryers do use electricity for the motor. It's the heat that comes from using gas.
@@jamesslick4790 Interesting! :)
I ask this question when I start covering electrical power systems for aircraft. The genesis is the light bulb. Aircraft use 400Hz to reduce the number of copper turns of the generators and reduce the size of cores in transformers.. On large transport aircraft with long cable runs, Aluminum is used and spiced with Copper for the generator feeders and the feeds into the distribution centers. On most commercial aircraft DC voltage is a higher 28 vs 12 on cars, similar purpose to save weight by making the wire size smaller because of reduced current. So happy to find your videos.
Correction - Aircraft use 400Hz to reduce the heavy Iron mass in transformers,
alternators and the like !
@@pjeaton58 Correct! I was going to say "inductors" but transformers will work.
@@pjeaton58 Thanks for the feedback, but I keep finding generators and alternators smaller at 400Hz
@@joeozzie1 yes because for a given voltage, the magnetic flux proportional to volt-seconds, is reduced at higher frequenies requiring less core. Also since reactance is proportional to frequency, the number of turns can be reduced while keeping magnitizing current the same. The reduced number of turns also reduces resistance.
Taken to the limit you end up with switch mode power supplies that use very small transformers operating at hundreds of kilocycles or even into the low MHz.
@@power-max Thanks, I thought so.
Awesome content! Great job!
Awesome! Thank you for using CZcams the right way! I love learning!
Im not a journeyman but Ive done plenty of my own electrical work. Really enjoyed this history lesson! Thanks.
A great video. I love physics and I love history. I see by some of the comments one person already made a comment concerning your error of more lighting filaments being more resistance which is exactly backwards but what astounds me is that you were able to mention the whole thing concerning AC without mentioning Nikola Tesla. And the reason the generators were in the basement before Nikola Tesla's invention was Thomas Edison was a DC man. DC cannot be transmitted over long distances so each building had to have a generator in the basement.
DC can easily be transmitted over long distances and it is very good for that, because the DC current lacks skin effect in the conductors. That's one reason why many of the high power links are realized with HVDC. In the early days the problem with DC was voltage conversion as it can't be done with traditional iron core transformers like it is done with AC. Anyway higher voltage is required for minimizing the transmission losses. Therefore AC was chosen instead of DC in most places.
@@laakeri84 Yep. And for a given size of conductor, the losses increase as the frequency increases.
Higher voltage means lower current - which reduces the I squared R loss. For example, a 120 Volt line carrying 100 amps will have 4 times the resistive losses as a 240 volt line carrying 50 amps.
Great channel, excellent presentation. I just discovered this channel. You are wonderful.
That was really interesting to watch, thank you. I'm British and always wondered about the evolution of the American electrical system, you explained it brilliantly.
She is wrong, we have both 110v and 220v in the US.
Edison was very concerned about safety and 110V is a little bit safer than 220 so far as electrical shock is concerned.
220V allows using smaller wire and thus its cheaper to implement.
I noticed this right away when I bought an extension cord in the Philippines. It's much more flexible than one from the US.
But Edison pushed for DC which is far more dangerous, it was Teslas 3 phase ac system that won the electricity war in the US.
Edison played the safety card because he wanted to use DC power. Not AC. Edison shocked his employees (as motivation and to wake them up), had a wire run around the shop that was used as pest control (not exactly something safe), he also electrocuted dogs to death to demonstrate the deadly unsafe power of AC current & an Elephant that was said to be bad/out of control after it attacked & I believe killed someone that abused the pour already often abused elephant.
Edison got to showcase his motion picture recording device. Along with this. The thing he tried to use his patents to basically be the film industry. But, a judge ruled against him and Hollywood was born. (Or something like that.)
I wouldn't say he was big on safety. As much as I'd say he was trying to turn the public on the much better competition. He was a businessman. If anyone today tried a fraction of the things he did the public would shun him so fast. People would be sending smoke signals before using the Edison Phone, camera, light bulb, or any other thing with his name on it.
Like here Finland one phase is 230V 50Hz and between phases 400V (3 phase)
At 230v the advantage is that thinner cable can be used relative to the load than the 120V system uses.
Great video! Very clear information
Best explanation I’ve ever had on this topic 😊
At 12:24 Kathy mentions higher-powered devices requiring higher voltages. I might add to her explanation: This same high power could be achieved with 120 VAC, but by stepping voltage up to 240 VAC the required current was cut in half (Power = Voltage x Current). Thus SMALLER CONDUCTORS could be used at 240 VAC vs 120 VAC.
What is vac?! 220-240 volts is allways better than 110 volts!
Smaller conducters!? What do you mean?!
@@GeirRssaak Conductors are sized according the the rating of the circuit breaker, which in turn is sized according to the load, and the amount of current required for the load. Other rules apply, but that is the basics.
Great analysis. Lesser minds would have looked for whoever, in the entire history of electricity, happened to generate 120VAC first and just stop there. Kathy rightly realizes that it's FAR more important to follow the influence and adoption of an invention than just its first occurrence. Great stuff.
Great vid, thanks!😊
Excellent work ❤