*This free video took WEEKS to make!* If you’d like to support Paul’s efforts, links below: Watch ad-free here:➡ www.patreon.com/theengineeringmindset Get your excel sheets here:➡ tinyurl.com/3-phase-calcs Grab a 3 phase power mug here:➡ tinyurl.com/3-Phase-Power-Mug
Question for you guys. This video mainly features north american standard which is convenient since I am located there. But do you create another version of that video for Europeans with more prevalent European standards? Just curious. Great job BTW
Whenever you need massive smoth dc, running a delta wye and a wye wye going through a full wave bridge gives very smooth output, minimizing need for big choke coil.
Would e.g a 6 phase generator waste less energy into thermal energy? Like I wonder with our energy demands (e.g electric cars and like appliances that consumed insignificant power now kinda increased noticeably e.g a GPU can easily consume about 600watthours on its own if not more and that's without calculating the inefficiency of the PSU pulling power from the grid in order to provide 600watts to the GPU )
@@me1970 no if earth's core had a strong enough mgnetic field to produce power by spinning around a huge stator ring miles outside of the earth (which we wouldbt be able to put in orbit in the first place but lets ignore that) then you wouldnt be able to pick anything that had the slightest piece of metal on it simply because earth would pull it down towards its core ... you know like magnets do.. earths core has a magnetic field but only strong enough for us to detect with compasses or sensors not strong enough to actually have some real "pull" or magnetic intensity.
Worked as an industrial electrician, worked in electronics and now a manager of maintenance for a manufacturing plant. I have to say, the way you explained it is probably the easiest and clearest explanation I have ever heard. Well done!
@@haikaldaniel3790 Lol sorry no, the fat cats are freaking out because our profits are not matching Covid year gains. We sell home improvement products and covid was a huge boost in sales for us. Now that it is back to normal they feel they are 'losing money'. Greedy idiots. I have 2 months to retirement...
Yeah, where was this guy when I was first learning this stuff almost 30 years ago. He just explained it in seconds like it's nothing. My instructors made it so complicated and confusing.
I was industrial electrician as well, and already understood how 3 phase works, most people cant wrap their head around it, but I have an electronics engineering degree, and we got deep into the math . I still learned a lot , as I was curious as to why not more with 4 or 5 phases.
Thank you, I am not an electrician, but I always wondered what on earth they were talking about with "three phase." This is one of the clearest explanations I have seen!
@@dane1234abc1 Not exactly. Three phase is the most economical for starting, (rotating) and running electric motors. No extra equipment is needed to make it work.
Three phases was chosen because it creates the most economic rotating magnetic fields to start and run other motors. Single phase needs extra equipment.
From an old electrical engineer: This is an excellent explanation of 3 phase power. You addressed all main questions that one seeking to understand the subject might or should ask (OK, you at least addressed all the questions I had when I was learning the subject ... and more) and your explanations and visual aids are clear and unique. I am saving this for reference to use when my grandkids learn the subject.
@@EngineeringMindset A great video, particularly the explanation of RMS. One important point about 3 phase that you did not mention was that simply reversing 2 wires reverses the direction of rotation of a motor. This is vital for lifts and escalators, as well a useful in machine shops. Another, less important point was that in HV distribution, one phase is bonded to ground, making emergency tripping simpler. If they are not available already, a video on current transformer use in metering would be great, as well as a video on PAM wound motors having 2 adjacent pole asynchronous speeds. 4 to 6 pole is very useful in refrigeration compressors since it produces ideal torques. The 4 pole speed is ideal for use in temperature pull down.
Industrial electrician here👋. In my apprenticeship the idea of a neutral wire was one of the harder things to grasp. This video does a superb job of explaining not only that, but single and three phase power from generation to utilization! I've passed this on to my apprenticeship director to help the next generation easily acquire knowledge that I struggled with. Great job, sir! 🫡
I'd advise against passing this one. Electricians themselves, and in fact most instructors, are not themselves qualified to understand how non-electricians might grasp certain basic concepts. The reason for this is simple: you already understand them. You've lost the power to see where people lose the train of ideas. I recommend you find several beginners and learn by showing the video and watching and asking where they lose what makes sense. Ask pertinent questions at certain times, like after 3:00, can your student explain electron flow directionality through a wire at forward and reverse sine phase? I suspect most will not, because the video glosses over this.
There are 6 phase power systems, usually used for stuff that needs stiff DC power at lots of amps. Electroplating lots of steel, purifying copper from raw melt, and alumium smelting are a few applications.
Yes... The extra phases (e.g., six-phase) from the power source can be used to cancel out very objectionable low order load harmonic currents often associated with the rectifier type loads that you describe.
Generally acheived by adding a transformer with multiple secondaries that can be combined to phase-shift the winding voltages, so you supply 12-pulse or 18-pulse rectifiers. This reduces the harmonic currents on the supply side, and is commonly used on medium-voltage inverter drives to reduce the stress on the motor insulation and provide a lower harmonic voltage waveform
I just came here to learn about three phase circuits but now I know how different concepts link and work together. You arranged information in a way it was easy to digest. the amount of work which went into this is crazyyy! Thank you Engineer Mindset
Nice video. One thing that might benefit from further explanation, though, is that RMS is not used simply to take the negative values of the sine wave and make them positive. If you simply flip the negative half to positive, and take the mean, you get average voltage, but that is not the same as the value you'll get if you do the squaring, take the mean of that, and then take the square root of that. This is because power is related to voltage squared.
There’s a good reason why 3 phases are used, and it’s not just a “reasonable compromise”. 3 is minimum number of phases that allows for constant power at a passive load such a motor. He implied in the video that 3 phases would give a more consistent power but still varying (if that were true then it’d be reasonable to say that adding more phases would continue to smooth out the power). In actual fact 3 phases will supply CONSTANT power to a passive load such a motor (as long as the phases are balanced, and the load is well behaved). Any multiple of 3 would do the same, so 6, 9, 12 phases, but of course 3-phases is the simplest, requires fewest wires, and going to 6 or 9 phases would give no advantage. The power graphs at 3:42 and 10:22 aren’t correct for passive loads like motors or resistive heaters that he talks about. They show the kind of discontinuous power waveform that you see from active components like rectifiers. The correct power waveforms would look like sin^2(ωt+φ)
Retired EE here... snarfsnarf's comment is right on! The instantaneous sum of the three sine-squared phase power waveforms (displaced 120 degrees) add up to a constant value flat line with no ripple for balanced passive loads. Some specialized non-linear loads like large rectifiers can benefit from greater than three-phase power sources. For example, a six phase source can cancel otherwise objectionable low-order harmonics in the rectifier's load currents, specifically the 5th and 7th harmonic currents.
At 6 phases, it will be a better electric motor and / or generator. Due to the fact that 6 phases provide different efficiencies depending on the use, with that said, 3 phases is not that efficient at constant use. Look at all the 3 phase EV'S they suck big time due to them using 100kwh ++ batteries that's equal to a 120kw + generator due to the losses at full load.. Just saying 3 phases suck literally 😂😅😂😅
@@MA-is5hh 2015 Study showed that 6-phase was 1-1.74x better in terms of power transmission than 3-phase. It literally is better, 3-phase is cheap and basic compared to the returns of 6-phase. There is no mathematical limit, only an engineering limit.
OMG!!! I've always understood the effective meaning of RMS but never really thought about what it actually represented and how it was determined. This video really was exciting to watch and now I have a much better understanding of RMS. Thank you!!!!
As an engineer myself, I use this channel quite a bit to refresh myself on alot of these engineering concepts, especially electrical power. This channel provides the best and easiest to follow explanations by far. You can tell alot of work is put into it with the animations and the quality of the content. Thank you so much for this channel, it really makes me a better engineer and your delivery keeps me fully engaged and ready to learn more!!!
Very detailed video! You've explained things more clearly than the schools I paid thousands of dollars to do, in just a matter of minutes... I will be saving and referencing this video for later
This has to be one of the most valuable and useful videos I have ever seen. This is just incredibly well done. This is as close to a PERFECT instructional video as you can possibly get. Absolutely astounding quality of work here. Really, really well done. If UA-cam gave out awards for great videos, this one would be deserving of one, for sure. This one sets the bar!
In the US we refer to the regular residential service as split single phase; it just has a center tap on the secondary side of the transformer, tied to ground to split our mostly used 120V off. We also have 3-phase high leg delta that provides 120V, 120V, and 208V, P-G and 240V P-P, which is quite prevalent in smaller businesses and home shops , that use mostly 120V but have one or a few smaller 3-phase machines, as it can be accomplished with 2 transformers. And while rare you can find the occasional 346/600V 3-phase which is mostly only uses in more industrial businesses.
My apartment even has a shared neutral because of that. It allows you to cut down on the copper required by about a quarter as you're not duplicating the neutral. So, one hot from one phase and another from the other and both of them using the same neutral. It works, but it can be annoying for some things you might want to wire in.
Electrical Eng. and I still come back to your videos time to time. Your channel helped me graduate and it still continues to help me stay solid on my foundations.
I'm an electrical engineer with a masters degree, I learned from this video and I have to say it was described much more concisely than at University, very well done!
You might add, sometimes a delta configuration does have a neutral, this provides what's often referred to as a high leg delta, and we get 3 different voltages off a three phase system, typically 120V between phase A and C to neutral, 208V between phase B and neutral, and 240V between any two phases. A much less common high leg delta provides 240 / 415 / 480 volts, and usually you'll come across this system in commercial and industrial settings where the majority of the loads are 3 phase motors and line to line single phase equipment, while also requiring 120V power for general purpose lighting and receptacle loads. It is usually no longer installed for a new system today, instead the power company will provide you with a wye system unless there is a very specific reason for wanting a delta. Some farms and small commercial settings will have two transformers to provide a 120/240V 3 phase 4 wire open delta, when the customer has mostly single phase equipment while requiring limited 3 phase power for motor loads because it's a cheaper setup than a wye 120/208V which would require 3 transformers.
One three-phase transformer will cost the same or cheaper than two single-phase ones. So why invent nonsense with two single-phase transformers and deprive yourself of the benefits of a full-fledged three-phase network?
At about time 12:00 , the audio (incorrectly) says "squared" the value, whereas the text (correctly) says "took the square root of" the value. The purpose of Root-Mean-Squares is that, given a repeating wave form, the RMS of such a system will be equivalent to the power (voltage x current) in a DC system
As a fairly gifted child, I was good enough at Physics to compete in my country's Olympiad, yet the only subject I never ever could understand was electronics. I tried lots of things, all the way to university, I just couldn't get it. This is the first time in 30 years that I made any progress in my understanding of this stuff. Thanks so much!
Short answer: 3 phases are good enough for generating a smooth rotating magnetic field in motors + an even power output in general so no need to add more phases wich just adds cost and complexity.
9:34 I thought US residential always gets two phases: that's how our electric stoves, clothes dryers, and furnaces get 240v -- with a "two pole" breaker in the panel box that combines two 180° offset phases into a single circuit to power those bigger appliances. No idea how that "two phase"/"split phase" translates into what is happening on the power company's generator though. 12:34 and there is the answer. Awesome informative video!
As a car mechanic, I understand 12v DC systems thoroughly. I’m also an RC hobbyists, so I understand DC lipo voltages quite well also. AC voltages always confused the heck out of me, I never understand how there could be a “neutral” wire, because my brain has always been trained to understand positive and negative, and nothing more. I think I get it now
So, I don't know engines very well (EE here) but the voltage induced in AC due to a rotor's magnetic flux is kind of like firing pistons at different angles: most efficient when fired at max piston height. Firing a piston when a piston has provided less compression to the air/gas mixture will provide less force to the crankshaft. This is similar to how a rotor magnetic field will induce less voltage when the rotor field is not at a maximum when "cutting" a stator winding in a generator.
In Yugoslavia we have domestic 3 phase sockets, capable up to 9kW (11kW short term). Used for large space heaters, welders, stoves, 3 phase motors. Now even for 3 phase EV chargers.
Yugoslavia doesn't exist anymore. Is Serbia, Croatia, Montenegro, Slovenia, Macedonia and Bosnia- Herzegovina. In which year you live? As of 1991 SFR Yugoslavia ceased to exist.
@@Mladjasmilic for me not. But you can ask a Croatian. And you as far as I can see you are denying the present realities. I m not from any of the above country but this is the history. And... subject is closed from my side.
@@UncleHo5 In Slavic, Jug (Yug) means 'south' and Slavia 'land of Slavs' . So term Yugoslavia still refences not only the country, but also the whole region where south Slavs live. And, no, it does not include Bulgaria, as Bulgarian are Slavic speaking Bulgars, Turkic people, like Yiddish is term for German-speaking Jews. There are also terms like ex-Yu, Yugosphere, West Balkan, etc. As for language, standard Croatian, Bosnian, Serbian and Montenegrin are so similar, that there are maybe 50 words in everyday speak which are different. Macedonian and Slovene not so much. But Croatia has a problem with Yugoslavia, that is true. Few days ago they arrested members of 'Bijelo Dugme', a rock band from '70s and '80s for singing songs which have term 'Yugoslavia' in Lyrics.
I'd have done so much better in school exams had there been UA-cam back then. These things were much harder to grasp; teacher had much harder to work, we had to focus much harder, yet we couldn't always grasp all the nuances. Multimedia in education is the one of the biggest things to have happend. Salute these content creators. They are doing much better than people writing text-books.
Actually, a two-phase generator with phases 90 degrees apart (Nikola Tesla's original polyphase concept) ALSO delivers constant instantaneous total power (i.e. ripple free) into balanced passive loads. The trig identity sin^2(x) + cos^2(x) = 1 explains it.
@runnergo1398 DC just means the voltage never changes sign. If the voltage is constant, it will also be constant power, but constant power does not imply constant voltage, and multiphase AC can also deliver constant power.
@runnergo1398 For balanced three phase AC, the SUM of the pulsating instantaneous power in each phase adds up to a constant value... It's fortuitously just how the trig works out... It also means that the instantaneous torque that must be delivered to the generator shaft by the prime mover (e.g., the turbine) is also constant, not pulsating.
It's wild how I'm paying my university thousands of dollars each year to teach me things less effectively over the span of 4 months than a free UA-cam video can in 15 minutes
I would call this a perfect explanation, but that would be a legitimate understatement. Thank you to all involved for the effort! I can now offer this link instead of failing to efficiently explain 3-phase yet another day in a row. lol I am simply a much better student than I am any form of an educator. My explanations can easily SUCK as a result.
Most Dutch homes can, if they aren't already, switch from 1 phase to 3 phase for a fee. It does require a new fuse box or at least the upgrade of an existing fuse box but in terms of monthly service fees to the power company/network management company a 35 amp single phase connection costs the same as a 25 amp 3 phase connection.
In the USA, you can have 3 phase at your house, but the cost varies significantly depending on the power lines and the distance to your house. For example, my parent's house has a power line with all 3 phases right in front of the house, so the installation cost would be low. However, in my neighborhood, they run 3 phase down the main street, and only branch a single phase down each side street. So I'd have to pay for them to add two phases down half a mile of road - much more expensive. And if you live somewhere with underground power lines? The cost would be insane.
Well done. One of the best visual descriptions of basic power, production, and transmission I’ve seen. I am such a nerd that I bought two of your cups, one medium one large. Just because they’re so cool. I’ve been an automotive technician for just over 50 years. So understanding electrics has been a important part of my career. And boy has it changed rapidly. Understanding alternating current ( alternators), voltage regulators and bridged rectifiers With their effects on systems when failing is a large part of diagnostics. At home I had a poor connection on the Neutral at pole, that caused an imbalance between the phases. That the power company didn’t believe until I made them come out. Unfortunately it took out the ECU processors in both the newer washer and dryer. So understanding electricity translates to many areas. Subscribed, thanks again.😊
Thank you, glad it was useful and thank you for your support, I hope you enjoy them, much appreciated. Send a photo in, maybe we can publish it. Not sure how long you've been a subscriber, but just incase you missed it, we have also covered car alternators, car batteries and starter motors in previous videos along with differentials too!
Here in Switzerland pretty much all residential Houses are connected with 400v three phase. It is really useful for large appliances or charging electric cars.
That sounds similar to what we have in Sweden, (and no, we are not the same country :)) As far as i know, anything other than 3-phase 230/400v is non existent. Just curious, what is the what is the fixed cost for an electric connection in Switzerland? Our model is so far that we pay a fixed cost monthly for 16A main fuses, 20A and 25A is also common. (and on top of that the price of each kWh of course).
@@Sam2sham with the safety culture here thats not a problem. Also every house hets regularly inspected and all electrical installations testet. These inspectors are thorough and don’t miss the slightest difference from code or problem.
For the last 20 odd years I couldn't get my head around how Delta wiring only had 3 lives. Your brilliant graphic at 6:34 has explained EVERYTHING! thankyou.
There's several reasons for this, one is the alternating current and a cheap power supply. Another is that leds are often dimmed with pulse-width modulation, which isn't bad in principle, but often the pwm speed is too slow and causes a visible flicker. With car headlights that effect becomes super obvious if you see them in a mirror.
@@kendokaaa Every LED flickers on AC. But yes, properly build ones flicker in the range of kHz. There are cheap (and expensive) ones that flicker in "low" frequencies that you can easily detect with your smartphone - those should not be used. And there are cheap (and expensive) ones that do it properly.
Many years ago as a teenager I was mentored by John Roesel, who owned Precise Power Corporation. He had a small production shop and research lab stuck out in the woods, and made power conversion generators--taking conventional single phase AC and outputting a precise 60 or 400hz 3 phase supply. depending upon the model. Later I saw many of them in factories of one sort or another in places that 3 phase distribution grid power was not available. This was a big deal when the big wave of European cabinetry and milling equipment began showing up in production shops in the early 80s. All of them had highly efficient and compact 3 phase motors powering them...
If Tesla had not only theoretically patented the three-phase motor, but also built it, then he would have realized that he didn't need 6 cables for three-phase current. At the same time, in Europe, Mikhail Dobrowolski is already working with 3 lines of three-phase current. For this he received the German patent. Westinghouse obtained rights to both patents and then built with 3 lines, not with 6 lines like Tesla thought.
Tesla oroginally used a 2 phase 4 wire system and it can still be found in Philadelphia and Connecticut. A Scott transformer can transfer 3 phase into 2 phase 90 degrees from each oter or vica versa. You confused cable with wire.
I am 3 minutes down, and this is the best video on this topic, I have watched many videos and read many texts on this subject, and even though I understood this for most part, there were always some gaps in the understanding. I am guessing, by the time I finish watching this video, finally I will have comprehensive intuitive understanding about this topic.
_Finally I found one! When an engineer actually understands the fundamentals behind every technology, like you clearly do, and not just the equations, the result is a clear, accurate, convincing and memorable explanation... exactly what's in this video. Kudos to you for being a good engineer and a good teacher._
@@JustinLebo-d3t A 3 phase heater has at least 3 heating elements and while individual element will flicker, the sum of their heat outputs will be a constant without pulsation. That's assuming that they are purely resistive. Heaters, especially high temperature filaments, are not linear devices and their resistance changes with temperature and as a result, they produce some harmonics in the current, some of which would not be canceled out by 3 phase current. But generally speaking, 3 phase power provides constant power for linear loads ("dumb" devices).
Are we talking about the difference between three out of phase and three in phase resistors, for the purpose of producing the same HEAT? Is there any scenario where IR being pulsed above a handful of Hz will make a difference? Heat diffusion in whatever absorbs it is slow and _averagy_ !
@@Trombonauta While resistive heaters have their thermal inertia to smooth their output, the constant aspect is critical for big generators and inverters, as well as big industrial loads like motors. But even at a small home that has a 3 phase motors powering a heat pump or AC it's beneficial because the constant power and lack of pulsation decreases wear and noise.
Appreciate this video. You have just explained a good basic knowledge of electrical engineering in 14sih minutes better than my college did in 3 months. Keep up the phenomenal teaching
I really like how this video simplifies the concepts because it makes it so incredibly easy to actually understand what's going on. I never really understood why AC has 0 in the middle, but it makes a lot of sense now that I know it's because the generator is pushing and pulling instead of just "generating" electricity.
9:24 Why 69K to 12.4K? That ratio (5.56:1) seems "unnatural". (I wondered the same about the 230K to 69K drop, but that ratio is 3.333:1, which is "natural".)
Very nice video. I would comment on 3 phases in a "standard" home. I live in the central Europe and generally, at least nearby big cities, we do have 3-phase connections. I'd say it's a must for new installations because we need more and more power. One typical appliance that requires at least 2 phases is an induction cooking plate. And if you're a DIY hobbyist, there's plenty of 3-phase machines targeted at home/garage shop customers. So, in general, having 3-phase power at home is a nice thing
If you came for the title (which is “How 3 Phase Power works: why 3 phases?”), the answer for that is given in a single sentence in the mid of the video, without fully explaining. It explains what happens if you increase the phases, but doesn't discuss what happen if you decrease it and do not answer “why 3 phases” directly.
3 phases is the number of phases which was found to deliver the most power to devices without having to engineer in safeguards to keep the system viable. No one has demonstrated that adding more phases is economical and safe.
agreed, ive been scrubbing through looking for the "why not 2" and im not really seeing it. And in the comments, i learned it's because a Harley motor shakes a lot :shrug:
Mikhail Dolivo-Dobrovolsky invented 3 phase generator , 3 phase transformer and induction motor , in Germany 1890s. Same time in Sweden, Jonas Wenström received in 1890 a Swedish patent for same 3 phase system, that was start of ASEA, that is now part of ABB. Nikola Tesla in USA and John Hopkinson in UK, also came in conclusion that 3 phase system had something. So you had 4 men in 4 different countries that all came to same end result, 3 phase AC system, with practical experiments.
Multiple reasons for 3 phase are listed throughout the video, here are some key points 4:30 Explained how 3 phases provide constant power. Graphic shows “almost” and audio says “more constant” with some small ripple shown, at this point all phases are still separate circuits and we have built upon simple single, two and then three phase generator. 5:05 Explained how it provides equal spacing. 5:36 Explained how more phases means more cables, controls and protection equipment, complex infrastructure, more complex transformers and motors, harder to balance network and synchronise generators. 6:22 Explains how only 3 wires are needed which is cheaper. 7:26 Explained how neutral can be used to balance 7:54 Explained how we use single or three phase from same system 8:21 Explained how Wye and Delta are used for different scenarios. Examples uses same resistance and line voltage. 9:59 Explained how 3 phase allows more loads to be connected 10:17 Explained how 3 phase uses more energy but provides more heat 10:19 Compares single and 3 phase power, shows 3 phase power is consistent 10:36 Shows single phase and 3 phase motor. Single phase has capacitor 10:41 Shows comparison for 3 people v 1 person for motor analogy.
It's also important in distribution that in European countries a transformer can feed tens of houses, sometimes hundreds, multiple streets and the secondary side is also fused unlike in North America.
This is sort of wrong. Usually you have 1 substation (lets say it steps it down from the big transmission lines to 1200V) feeding a town of anywhere from 10,000-20,000. From there it it gets further stepped down on the pole to 120/240 split single phase as most of the grid is designed to be residential load based. Transformers are spaced out every 5-6 poles as step-up transformers to try and keep the secondaries on the poles at a constant voltage. Also the primary sides of the transformers on the poles are fused. In the event of a short or overload on the secondaries of the pole transformers, the utility expects the transformer to blowup as the fuse which in turn would blow the primary side fuse (though this does take a big short/overcurrent and time to cause). Also most substations are equipped with circuit breakers in the event the secondaires out of the substation were to short out. In terms of a Commercial application, the building gets its own transformer as seen in this video due to its needed a 3-phase hookup of either 120/208 or 480/277 depending on the loads the space needs (also the video does fail to show that 277V lighting is a thing). The only time a house would get its own transformer is for one of 2 reasons. The first reason is that is a higher amperage house than normal (higher than 200-300 AMPS). This results in the utility either giving the house its own transformer on the pole or having a transformer installed on the persons property. The other reason occurs when you get to the low population density areas where houses are easily a .25mile to .5mile apart and it is not feasible to have a step-up transformer every 5-6 poles.
This educational video is a gem. I've learnt this kind of stuff on a theoretical basis back in school but your way of visualising makes it all quite easy to understand. Well done.
Why 3? Is because is a reasonable number, could have been anything, but less than 3 makes motors lose power during the deeps, more phases is just too much.
Not really, it wasn't an arbitrary choice. 3 is the minimum number of phases to supply constant power to a passive load (e.g. motor or heater). Any multiple of 3 (6, 9. 12-phase!) would do the same but going to 6 or 9 phases would give no advantage.
@@snarfsnarfs That's what I said... BTW, 3 phases do not supply constant power, the power still drops, but not that much to cause instabilities in mechanical outputs.
@@gabrielbarrantes6946 in an ideal system the power doesn't drop at all. It is constant power all the way through the cycle. As the instantaneous power from the 1st phase starts to drop, the other 2 phases start to deliver that power in the exact proportion that the sum total stays constant. For circuits containing active components it's different, but for passives like motors/heaters/etc the sum total stays constant through the cycle.
@@snarfsnarfs 2 phases shifted by 90° also show constant power. But then you need 4 wires (two separate phases) or 3 wires (one common to both phases). The current in the common wire is sqrt(2) higher, so a thicker wire is needed. But if you need 3 wires anyway, a three phase system is the optimal solution. as then the current in the common wire is zero and this wire can be omitted. Anyway: you are perfectly right: power is constant in an ideal system, while in the video is said: in an ideal system power still varies a little.
@@RainerNase-b3q That's a really good point. 😀 In the 3phase case we have: p1+p2+p3 = sin^2(x) + sin^2(x + 2×π/3) + sin^2(x - 2×π/3) = 1.5 In the 2phase case it's also constant as you said: p1+p2 = sin^2(x) + sin^2(x + π/2) = 1 I never really thought of it like that before. As you said it still ends up requiring an extra wire (or a thicker common wire) than the 3ph case anyway. Thanks for raising the interesting point. 😀
I absolutely agree that your explanations are EXCELLENT, clear, concise and simple, you have clarified why we use 3 phase, why we step up the voltage on transmission lines and the differences between 3 and single phase star or Delta etc. ....as an electronics hobbyist of over 50 years one question still escapes me though..... why, here in the UK for example did we settle on 50Hz, why do some countries use 60Hz and why not use, say, 100 or 200 Hz etc which would surely be more efficient.....
I have literally no experience in this, but I’m curious as to why it would be out of phase there. The highlighted area under the curve shows the wave to be at 0 when the magnet is parallel to the coil. Would that not be the case? From someone with no experience that seems correct, but If it’s wrong I’d be interested to know why.
Excellent tutorial. If these concepts were taught in schools this way then more people would be interested in the various electrical tradecrafts. You answered questions that have been lingering in my brain for the last 40 years while working as a tech in plant maintenance. Direct Current is easy and straight forward. Alternating Current is more complicated but you have done an outstanding job with illustrating the concepts and simplifying the alleged mysteries. Well done. I'm subscribing. (i.e. I always wondered the reasons why Delta and Wye were used in 3 phase circuits)
Very well done, thank you! 3-phase is the biggest bang for the customer's buck, with only 3 wires, only one additional wire compared to single phase. For some high power machines, 5-phase is better, although more costly (but less ripple and conductor size is reduced). Both 4-phase and 6-phase are basically useless for motors, the increased cost gains you nothing over 3-phase and 5-phase respectively. However 6-phase is a nice low-cost solution for so-called "rectifier front ends" converting to DC with very low ripple, and is easy to implement with the right transformer connections. This is the best video I've seen on the topic.
I lost it when the electrical worker walked away from the global power standards! I've felt that way for decades. Thank you. Your explanation of 3 phase was the best I've seen .
A valuable video explaining three-phase current. Many people think it is just one current (going by the name). I think coils in the stator of the generator are positioned radially from the center, and not along the circumference, for better magnetic field penetration/change. This is demonstrated at 1:10 into the video.
I liked the infographic of single vs. 3 phase motors, depicting one person trying the crank vs. 3 people passing the crank. In north America, the secondary 120/240 is referred to as "split phase", as phase to neutral provides half of the phase to phase single phase wave voltage by tapping the transformer in the middle.
Electrical Engineering used to be one of my favorite subjects while pursuing Computer Science engineering. And for some reason I felt an itch to revisit the concept of phases. And I'm glad I came across this channel. Definitely explained better than my college professor 😅
Awesome explanation, thanks. I knew the generator magnet spun in a circle and 360/3 is 120 degrees per phase, but I didn’t know how those phases overlapped in terms of the currents.
This tutorial showed up just when I needed it. I was recently looking at some high voltage lines in the area and wondering why there were three wires. But before I got around to trying to look it up your video showed up and answered the question for me. Thanks for the great explanation of 3 phase power.
9:06 It's worth mentioning that the reason high voltage is used is because the loss in the wires is given by (Current squared x Resistance of wires). So halve the current by doubling the voltage (for a given wattage of power delivered) then you quarter the losses. This permits the use of relatively modestly sized transmission cables, when you consider the power they are delivering. Very high voltage means fairly low current flow and yet still a good power delivery. The upper limit being, how to insulate very high voltages on the lines and make safe and effective transformers to step up and down and the ends.
Nice explanation! Except for the RMS part, that honestly shocked me a bit - it's certainly not just that "someone realized" heat production in a resistor and experimentally figured out the ratio approximating sqrt(2), you can really calculate that knowing that P = U*I = U²/R (which, yes, "someone" realized at some point), calculating the average power noticing that sin² averages to half the (squared) peak and taking the square root of 1/2 to obtain exactly the sqrt(2)
This was great, I need 3-phase explained to me like every few months. We indeed have 3-phase residentially in my part of the world, used for storage heaters, and some old ovens, but mostly unnecessary. This explanation simplifies nicely what I have to do to convert a 3-phase socket to single-phase - just connect neutral and one of the phases.
*This free video took WEEKS to make!* If you’d like to support Paul’s efforts, links below:
Watch ad-free here:➡ www.patreon.com/theengineeringmindset
Get your excel sheets here:➡ tinyurl.com/3-phase-calcs
Grab a 3 phase power mug here:➡ tinyurl.com/3-Phase-Power-Mug
Question for you guys. This video mainly features north american standard which is convenient since I am located there. But do you create another version of that video for Europeans with more prevalent European standards? Just curious. Great job BTW
Whenever you need massive smoth dc, running a delta wye and a wye wye going through a full wave bridge gives very smooth output, minimizing need for big choke coil.
Would e.g a 6 phase generator waste less energy into thermal energy? Like I wonder with our energy demands (e.g electric cars and like appliances that consumed insignificant power now kinda increased noticeably e.g a GPU can easily consume about 600watthours on its own if not more and that's without calculating the inefficiency of the PSU pulling power from the grid in order to provide 600watts to the GPU )
If the Earth's core is just a big magnet, could we put huge rotating stators in orbit around the Earth and create energy?
@@me1970 no if earth's core had a strong enough mgnetic field to produce power by spinning around a huge stator ring miles outside of the earth (which we wouldbt be able to put in orbit in the first place but lets ignore that) then you wouldnt be able to pick anything that had the slightest piece of metal on it simply because earth would pull it down towards its core ... you know like magnets do.. earths core has a magnetic field but only strong enough for us to detect with compasses or sensors not strong enough to actually have some real "pull" or magnetic intensity.
Worked as an industrial electrician, worked in electronics and now a manager of maintenance for a manufacturing plant. I have to say, the way you explained it is probably the easiest and clearest explanation I have ever heard. Well done!
Have a job vacancy? 😅
@@haikaldaniel3790 Lol sorry no, the fat cats are freaking out because our profits are not matching Covid year gains. We sell home improvement products and covid was a huge boost in sales for us. Now that it is back to normal they feel they are 'losing money'. Greedy idiots. I have 2 months to retirement...
thanks for making me feel more stupider... if that's even a word...
Yeah, where was this guy when I was first learning this stuff almost 30 years ago. He just explained it in seconds like it's nothing. My instructors made it so complicated and confusing.
I was industrial electrician as well, and already understood how 3 phase works, most people cant wrap their head around it, but I have an electronics engineering degree, and we got deep into the math . I still learned a lot , as I was curious as to why not more with 4 or 5 phases.
I understand now but 100% will return in the future when I forget and have another knowledge crisis. 😂
😂 😂😂
😂😂😂
When that happens don't worry .....it's just a phase
Seeya tomorrow!
Good luck using it tho
Thank you, I am not an electrician, but I always wondered what on earth they were talking about with "three phase." This is one of the clearest explanations I have seen!
As an ordinary person This video is still hard to understand 😂
Three phases is the fewest number of phases whose average power is a constant. That’s why three phase electricity versus four, five, six… phases.
@@dane1234abc1 Not exactly. Three phase is the most economical for starting, (rotating) and running electric motors. No extra equipment is needed to make it work.
Three phases was chosen because it creates the most economic rotating magnetic fields to start and run other motors. Single phase needs extra equipment.
@@dane1234abc1, no, two phases are enough.
Another EE here... This is a phenomenally well crafted visualization of the physics of AC power generation and distribution. Well done.
From an old electrical engineer: This is an excellent explanation of 3 phase power. You addressed all main questions that one seeking to understand the subject might or should ask (OK, you at least addressed all the questions I had when I was learning the subject ... and more) and your explanations and visual aids are clear and unique. I am saving this for reference to use when my grandkids learn the subject.
This video has taught me more about the power grid and home electricity in 15 minutes than I managed to learn in nearly 35 years living on this earth.
in the intro it completely overlooks the fact that 230VAC systems exist. I.E. in Europe and parts of Asia...
@@TheExileFox who cares. the principles are identical and he addresses it later in the video.
@@billwall267 I care
@@UmVtCg no you don't
Same!
As a Electrical Engineering Major ... well done. You did a better job explaining then any of my professors did
believe me or not but this is exactly the type of video I was searching for since school started, I can't explain with words how thankful I am
Glad to hear, hope it helps with your studies. If you can share links to your class mates so we help even more people that would be much appreciated
@@EngineeringMindset A great video, particularly the explanation of RMS.
One important point about 3 phase that you did not mention was that simply reversing 2 wires reverses the direction of rotation of a motor. This is vital for lifts and escalators, as well a useful in machine shops.
Another, less important point was that in HV distribution, one phase is bonded to ground, making emergency tripping simpler.
If they are not available already, a video on current transformer use in metering would be great, as well as a video on PAM wound motors having 2 adjacent pole asynchronous speeds. 4 to 6 pole is very useful in refrigeration compressors since it produces ideal torques. The 4 pole speed is ideal for use in temperature pull down.
@@EngineeringMindset love you man
Your content is awesome I am feeling real engineering
Industrial electrician here👋. In my apprenticeship the idea of a neutral wire was one of the harder things to grasp. This video does a superb job of explaining not only that, but single and three phase power from generation to utilization! I've passed this on to my apprenticeship director to help the next generation easily acquire knowledge that I struggled with. Great job, sir! 🫡
I'd advise against passing this one. Electricians themselves, and in fact most instructors, are not themselves qualified to understand how non-electricians might grasp certain basic concepts. The reason for this is simple: you already understand them. You've lost the power to see where people lose the train of ideas. I recommend you find several beginners and learn by showing the video and watching and asking where they lose what makes sense. Ask pertinent questions at certain times, like after 3:00, can your student explain electron flow directionality through a wire at forward and reverse sine phase? I suspect most will not, because the video glosses over this.
As a retired high school teacher I applaud this detailed, succint explanation. Superb graphics and equations and well paced.
I love a succinct Chinese meal.
There are 6 phase power systems, usually used for stuff that needs stiff DC power at lots of amps. Electroplating lots of steel, purifying copper from raw melt, and alumium smelting are a few applications.
Yes... The extra phases (e.g., six-phase) from the power source can be used to cancel out very objectionable low order load harmonic currents often associated with the rectifier type loads that you describe.
Generally acheived by adding a transformer with multiple secondaries that can be combined to phase-shift the winding voltages, so you supply 12-pulse or 18-pulse rectifiers. This reduces the harmonic currents on the supply side, and is commonly used on medium-voltage inverter drives to reduce the stress on the motor insulation and provide a lower harmonic voltage waveform
One could also use a 3 ph motor to drive a generator/ alternator of choice, for those localized requirements.
Also 400 cycle for high power electronics.
@@warrenpuckett4203And civil aircraft
I just came here to learn about three phase circuits but now I know how different concepts link and work together. You arranged information in a way it was easy to digest. the amount of work which went into this is crazyyy! Thank you Engineer Mindset
Nice video. One thing that might benefit from further explanation, though, is that RMS is not used simply to take the negative values of the sine wave and make them positive. If you simply flip the negative half to positive, and take the mean, you get average voltage, but that is not the same as the value you'll get if you do the squaring, take the mean of that, and then take the square root of that. This is because power is related to voltage squared.
There’s a good reason why 3 phases are used, and it’s not just a “reasonable compromise”. 3 is minimum number of phases that allows for constant power at a passive load such a motor.
He implied in the video that 3 phases would give a more consistent power but still varying (if that were true then it’d be reasonable to say that adding more phases would continue to smooth out the power). In actual fact 3 phases will supply CONSTANT power to a passive load such a motor (as long as the phases are balanced, and the load is well behaved). Any multiple of 3 would do the same, so 6, 9, 12 phases, but of course 3-phases is the simplest, requires fewest wires, and going to 6 or 9 phases would give no advantage.
The power graphs at 3:42 and 10:22 aren’t correct for passive loads like motors or resistive heaters that he talks about. They show the kind of discontinuous power waveform that you see from active components like rectifiers. The correct power waveforms would look like sin^2(ωt+φ)
Thank for writing this for all of us =)
It would still vary in real life due to magnetic saturation, shape of the magnetic field and so much more tho, that's why 5 phase motor exists
Retired EE here... snarfsnarf's comment is right on! The instantaneous sum of the three sine-squared phase power waveforms (displaced 120 degrees) add up to a constant value flat line with no ripple for balanced passive loads.
Some specialized non-linear loads like large rectifiers can benefit from greater than three-phase power sources. For example, a six phase source can cancel otherwise objectionable low-order harmonics in the rectifier's load currents, specifically the 5th and 7th harmonic currents.
At 6 phases, it will be a better electric motor and / or generator.
Due to the fact that 6 phases provide different efficiencies depending on the use, with that said, 3 phases is not that efficient at constant use. Look at all the 3 phase EV'S they suck big time due to them using 100kwh ++ batteries that's equal to a 120kw + generator due to the losses at full load..
Just saying 3 phases suck literally 😂😅😂😅
@@MA-is5hh 2015 Study showed that 6-phase was 1-1.74x better in terms of power transmission than 3-phase. It literally is better, 3-phase is cheap and basic compared to the returns of 6-phase. There is no mathematical limit, only an engineering limit.
Why am i watching this instead of sleeping? I have a degree in electrical engineering
It's 2:45 am. I also have an EE degree. Wtf are we doing.
😂
It’s fun to watch and you want to hear someone try a dnteach what you know so well. 😁
@@burnte I'm a pulsed power EE. I haven't touched 3 phase since college 🤣 from what I remember this is a great explanation
Because knowledge is different type of love which can’t be explained 😅
OMG!!! I've always understood the effective meaning of RMS but never really thought about what it actually represented and how it was determined. This video really was exciting to watch and now I have a much better understanding of RMS. Thank you!!!!
13:15 with a FULL BRIDGE RECTIFIYAH!!!
You mean FOOOL
- Mehdi Sadaghdar
Exactly, video about it here: ua-cam.com/video/RiRyzLl4Y8U/v-deo.html
@@EngineeringMindset you did not get the reference did you lol
Electroboom have set a standard here, albeit unofficial. 😄
As an engineer myself, I use this channel quite a bit to refresh myself on alot of these engineering concepts, especially electrical power. This channel provides the best and easiest to follow explanations by far. You can tell alot of work is put into it with the animations and the quality of the content. Thank you so much for this channel, it really makes me a better engineer and your delivery keeps me fully engaged and ready to learn more!!!
This is high quality, EE here, and you nailed everything perfectly
And without clogging an exhausted brain with endless formulas, as is done in university.
I am a Mechanical engineer.Still I understood everything. The explanation was more crisp and clear. Thanks a ton man.
This is one of the best instructional videos I’ve ever seen. Well done! - Jim (PhD EE)
Amazing explanation, I have watched many videos, listened to many teachers , but no one explained 3 phase like you did. Please keep doing it.
Very detailed video! You've explained things more clearly than the schools I paid thousands of dollars to do, in just a matter of minutes... I will be saving and referencing this video for later
This has to be one of the most valuable and useful videos I have ever seen. This is just incredibly well done. This is as close to a PERFECT instructional video as you can possibly get. Absolutely astounding quality of work here. Really, really well done. If UA-cam gave out awards for great videos, this one would be deserving of one, for sure. This one sets the bar!
I'm only 2:30 in, but i want to say thank you for explaining AC in that way. I feel like I understand it a lot better now.
You managed to explain this better in 15 minutes than one of my professors in two weeks of lectures. Very nice video, kudos.
In the US we refer to the regular residential service as split single phase; it just has a center tap on the secondary side of the transformer, tied to ground to split our mostly used 120V off. We also have 3-phase high leg delta that provides 120V, 120V, and 208V, P-G and 240V P-P, which is quite prevalent in smaller businesses and home shops , that use mostly 120V but have one or a few smaller 3-phase machines, as it can be accomplished with 2 transformers. And while rare you can find the occasional 346/600V 3-phase which is mostly only uses in more industrial businesses.
Absolutely, we covered in detail in our previous video here: ua-cam.com/video/u0SsejDCVkU/v-deo.html
347/600V is actually commonly used instead of 277/480V in Canada
My apartment even has a shared neutral because of that. It allows you to cut down on the copper required by about a quarter as you're not duplicating the neutral. So, one hot from one phase and another from the other and both of them using the same neutral. It works, but it can be annoying for some things you might want to wire in.
👍 split single phase
3 phase 480 isn't all that rare. Just about all manufacturers have 3 phase 480 systems. Canada uses 600V systems.
Electrical Eng. and I still come back to your videos time to time.
Your channel helped me graduate and it still continues to help me stay solid on my foundations.
The single best video I've seen describing power generation and tranformation.
I'm an electrical engineer with a masters degree, I learned from this video and I have to say it was described much more concisely than at University, very well done!
You might add, sometimes a delta configuration does have a neutral, this provides what's often referred to as a high leg delta, and we get 3 different voltages off a three phase system, typically 120V between phase A and C to neutral, 208V between phase B and neutral, and 240V between any two phases. A much less common high leg delta provides 240 / 415 / 480 volts, and usually you'll come across this system in commercial and industrial settings where the majority of the loads are 3 phase motors and line to line single phase equipment, while also requiring 120V power for general purpose lighting and receptacle loads. It is usually no longer installed for a new system today, instead the power company will provide you with a wye system unless there is a very specific reason for wanting a delta.
Some farms and small commercial settings will have two transformers to provide a 120/240V 3 phase 4 wire open delta, when the customer has mostly single phase equipment while requiring limited 3 phase power for motor loads because it's a cheaper setup than a wye 120/208V which would require 3 transformers.
Absolutely, we covered it in great detail with step by step math in our last video here: ua-cam.com/video/u0SsejDCVkU/v-deo.html
One three-phase transformer will cost the same or cheaper than two single-phase ones. So why invent nonsense with two single-phase transformers and deprive yourself of the benefits of a full-fledged three-phase network?
My father was an outstanding electrical engineer, and explained some of this to me, but this explanation is the best I have ever seen.
At about time 12:00 , the audio (incorrectly) says "squared" the value, whereas the text (correctly) says "took the square root of" the value.
The purpose of Root-Mean-Squares is that, given a repeating wave form, the RMS of such a system will be equivalent to the power (voltage x current) in a DC system
As a fairly gifted child, I was good enough at Physics to compete in my country's Olympiad, yet the only subject I never ever could understand was electronics. I tried lots of things, all the way to university, I just couldn't get it. This is the first time in 30 years that I made any progress in my understanding of this stuff. Thanks so much!
Short answer: 3 phases are good enough for generating a smooth rotating magnetic field in motors + an even power output in general so no need to add more phases wich just adds cost and complexity.
9:34 I thought US residential always gets two phases: that's how our electric stoves, clothes dryers, and furnaces get 240v -- with a "two pole" breaker in the panel box that combines two 180° offset phases into a single circuit to power those bigger appliances.
No idea how that "two phase"/"split phase" translates into what is happening on the power company's generator though.
12:34 and there is the answer. Awesome informative video!
As a car mechanic, I understand 12v DC systems thoroughly. I’m also an RC hobbyists, so I understand DC lipo voltages quite well also. AC voltages always confused the heck out of me, I never understand how there could be a “neutral” wire, because my brain has always been trained to understand positive and negative, and nothing more. I think I get it now
So, I don't know engines very well (EE here) but the voltage induced in AC due to a rotor's magnetic flux is kind of like firing pistons at different angles: most efficient when fired at max piston height. Firing a piston when a piston has provided less compression to the air/gas mixture will provide less force to the crankshaft. This is similar to how a rotor magnetic field will induce less voltage when the rotor field is not at a maximum when "cutting" a stator winding in a generator.
You can think of the negative side of the battery as a neutral. Both serve as a path for current to return to the source.
Anyone starting out in the world of electrical is very lucky these days. Great having good content for the learners. 👍
In Yugoslavia we have domestic 3 phase sockets, capable up to 9kW (11kW short term).
Used for large space heaters, welders, stoves, 3 phase motors. Now even for 3 phase EV chargers.
Yugoslavia doesn't exist anymore. Is Serbia, Croatia, Montenegro, Slovenia, Macedonia and Bosnia- Herzegovina. In which year you live? As of 1991 SFR Yugoslavia ceased to exist.
@@UncleHo5 Does it really matter? It is all the same...
@@Mladjasmilic for me not. But you can ask a Croatian. And you as far as I can see you are denying the present realities. I m not from any of the above country but this is the history. And... subject is closed from my side.
@@UncleHo5 In Slavic, Jug (Yug) means 'south' and Slavia 'land of Slavs' . So term Yugoslavia still refences not only the country, but also the whole region where south Slavs live. And, no, it does not include Bulgaria, as Bulgarian are Slavic speaking Bulgars, Turkic people, like Yiddish is term for German-speaking Jews.
There are also terms like ex-Yu, Yugosphere, West Balkan, etc.
As for language, standard Croatian, Bosnian, Serbian and Montenegrin are so similar, that there are maybe 50 words in everyday speak which are different. Macedonian and Slovene not so much.
But Croatia has a problem with Yugoslavia, that is true. Few days ago they arrested members of 'Bijelo Dugme', a rock band from '70s and '80s for singing songs which have term 'Yugoslavia' in Lyrics.
@@Mladjasmilic Thank you for this info, I was curious to understand this part of the world more, unlike the other person who replied to you...
I'd have done so much better in school exams had there been UA-cam back then. These things were much harder to grasp; teacher had much harder to work, we had to focus much harder, yet we couldn't always grasp all the nuances.
Multimedia in education is the one of the biggest things to have happend. Salute these content creators. They are doing much better than people writing text-books.
Actually, a two-phase generator with phases 90 degrees apart (Nikola Tesla's original polyphase concept) ALSO delivers constant instantaneous total power (i.e. ripple free) into balanced passive loads. The trig identity sin^2(x) + cos^2(x) = 1 explains it.
that is actually a 4-phase motor.
@@andrewgrillet5835 Nope. Two-phase, 4-wire.
I thought constant would be DC? AC no matter what is bouncing back and forth.
@runnergo1398 DC just means the voltage never changes sign. If the voltage is constant, it will also be constant power, but constant power does not imply constant voltage, and multiphase AC can also deliver constant power.
@runnergo1398 For balanced three phase AC, the SUM of the pulsating instantaneous power in each phase adds up to a constant value... It's fortuitously just how the trig works out... It also means that the instantaneous torque that must be delivered to the generator shaft by the prime mover (e.g., the turbine) is also constant, not pulsating.
You have no idea how long it took me to figure out why we used RMS values. Fantastic video. People don't realise how simple and thorough this is.
The answer is at 5:25
4:30 If you add the output powers of the phases, the total power is not almost constant, but exactly constant.
It's wild how I'm paying my university thousands of dollars each year to teach me things less effectively over the span of 4 months than a free UA-cam video can in 15 minutes
I spent around $300 to learn about DC and AC circuit online. Money well spent! The same cource will probably cost 3 times as much at a university.
Old money bag technology. Vs raw information.✓
you at university still don't understand why u there, what they're.
you going to university to receive the recognition only. even you know everything in this world but no 1 recognise you then no 1 believing you.
I would call this a perfect explanation, but that would be a legitimate understatement. Thank you to all involved for the effort!
I can now offer this link instead of failing to efficiently explain 3-phase yet another day in a row. lol
I am simply a much better student than I am any form of an educator. My explanations can easily SUCK as a result.
Most Dutch homes can, if they aren't already, switch from 1 phase to 3 phase for a fee. It does require a new fuse box or at least the upgrade of an existing fuse box but in terms of monthly service fees to the power company/network management company a 35 amp single phase connection costs the same as a 25 amp 3 phase connection.
In the USA, you can have 3 phase at your house, but the cost varies significantly depending on the power lines and the distance to your house. For example, my parent's house has a power line with all 3 phases right in front of the house, so the installation cost would be low. However, in my neighborhood, they run 3 phase down the main street, and only branch a single phase down each side street. So I'd have to pay for them to add two phases down half a mile of road - much more expensive. And if you live somewhere with underground power lines? The cost would be insane.
Anything newly built in the last two decades in NL already has three phase as default in the "meterkast"
@@MichielKlaverThe wiring is there but it's not hooked up by default though, as far as I know 🤔
@@pyramidsinegypt the new hosing projects I've visited the past 10-15 years all had 3-phase main breakers. Probably the heat-pumps are to blame
@@MichielKlaver Ah yeah, I think you're right.
Well done. One of the best visual descriptions of basic power, production, and transmission I’ve seen. I am such a nerd that I bought two of your cups, one medium one large. Just because they’re so cool. I’ve been an automotive technician for just over 50 years. So understanding electrics has been a important part of my career. And boy has it changed rapidly. Understanding alternating current ( alternators), voltage regulators and bridged rectifiers With their effects on systems when failing is a large part of diagnostics. At home I had a poor connection on the Neutral at pole, that caused an imbalance between the phases. That the power company didn’t believe until I made them come out. Unfortunately it took out the ECU processors in both the newer washer and dryer. So understanding electricity translates to many areas. Subscribed, thanks again.😊
Thank you, glad it was useful and thank you for your support, I hope you enjoy them, much appreciated. Send a photo in, maybe we can publish it. Not sure how long you've been a subscriber, but just incase you missed it, we have also covered car alternators, car batteries and starter motors in previous videos along with differentials too!
Here in Switzerland pretty much all residential Houses are connected with 400v three phase. It is really useful for large appliances or charging electric cars.
That sounds similar to what we have in Sweden, (and no, we are not the same country :))
As far as i know, anything other than 3-phase 230/400v is non existent.
Just curious, what is the what is the fixed cost for an electric connection in Switzerland?
Our model is so far that we pay a fixed cost monthly for 16A main fuses, 20A and 25A is also common.
(and on top of that the price of each kWh of course).
Sounds a little dangerous, but can use much smaller copper wires and reduce cist.
@@Sam2sham why would that be dangerous? ever been to Switzerland? here is everything up to code and security is taken extremely serious
@@Superbus753 just the extreme voltage.
@@Sam2sham with the safety culture here thats not a problem.
Also every house hets regularly inspected and all electrical installations testet. These inspectors are thorough and don’t miss the slightest difference from code or problem.
For the last 20 odd years I couldn't get my head around how Delta wiring only had 3 lives. Your brilliant graphic at 6:34 has explained EVERYTHING! thankyou.
Interesting little bit here: You can see cheap LEDs flicker. They cause some people, like my mother and I, headaches.
Car headlights, Christmas lights, and the aforementioned cheap bulbs. There's no end to the flickering
The old florescents flickered so fast you couldn't tell unless they were wearing out
There's several reasons for this, one is the alternating current and a cheap power supply. Another is that leds are often dimmed with pulse-width modulation, which isn't bad in principle, but often the pwm speed is too slow and causes a visible flicker. With car headlights that effect becomes super obvious if you see them in a mirror.
Even a lot of pricier LED bulbs flicker but at a much higher frequency
@@kendokaaa Every LED flickers on AC. But yes, properly build ones flicker in the range of kHz. There are cheap (and expensive) ones that flicker in "low" frequencies that you can easily detect with your smartphone - those should not be used.
And there are cheap (and expensive) ones that do it properly.
Many years ago as a teenager I was mentored by John Roesel, who owned Precise Power Corporation. He had a small production shop and research lab stuck out in the woods, and made power conversion generators--taking conventional single phase AC and outputting a precise 60 or 400hz 3 phase supply. depending upon the model. Later I saw many of them in factories of one sort or another in places that 3 phase distribution grid power was not available. This was a big deal when the big wave of European cabinetry and milling equipment began showing up in production shops in the early 80s. All of them had highly efficient and compact 3 phase motors powering them...
Society develops wit, but its contemplation alone forms genius.
Man, this is how school should look like, easy to understand explanation in a not boring form, excelent !!! Thank you !
If Tesla had not only theoretically patented the three-phase motor, but also built it, then he would have realized that he didn't need 6 cables for three-phase current.
At the same time, in Europe, Mikhail Dobrowolski is already working with 3 lines of three-phase current. For this he received the German patent.
Westinghouse obtained rights to both patents and then built with 3 lines, not with 6 lines like Tesla thought.
Tesla oroginally used a 2 phase 4 wire system and it can still be found in Philadelphia and Connecticut. A Scott transformer can transfer 3 phase into 2 phase 90 degrees from each oter or vica versa. You confused cable with wire.
I am 3 minutes down, and this is the best video on this topic, I have watched many videos and read many texts on this subject, and even though I understood this for most part, there were always some gaps in the understanding. I am guessing, by the time I finish watching this video, finally I will have comprehensive intuitive understanding about this topic.
_Finally I found one! When an engineer actually understands the fundamentals behind every technology, like you clearly do, and not just the equations, the result is a clear, accurate, convincing and memorable explanation... exactly what's in this video. Kudos to you for being a good engineer and a good teacher._
If he understood the equations he'd know that both 2 and 3 phase systems deliver constant power.
@@Ryrzard What do you mean by constant power? Wouldn't a resistive heater still flicker?
@@JustinLebo-d3t A 3 phase heater has at least 3 heating elements and while individual element will flicker, the sum of their heat outputs will be a constant without pulsation.
That's assuming that they are purely resistive. Heaters, especially high temperature filaments, are not linear devices and their resistance changes with temperature and as a result, they produce some harmonics in the current, some of which would not be canceled out by 3 phase current. But generally speaking, 3 phase power provides constant power for linear loads ("dumb" devices).
Are we talking about the difference between three out of phase and three in phase resistors, for the purpose of producing the same HEAT? Is there any scenario where IR being pulsed above a handful of Hz will make a difference? Heat diffusion in whatever absorbs it is slow and _averagy_ !
@@Trombonauta While resistive heaters have their thermal inertia to smooth their output, the constant aspect is critical for big generators and inverters, as well as big industrial loads like motors. But even at a small home that has a 3 phase motors powering a heat pump or AC it's beneficial because the constant power and lack of pulsation decreases wear and noise.
Appreciate this video. You have just explained a good basic knowledge of electrical engineering in 14sih minutes better than my college did in 3 months. Keep up the phenomenal teaching
the main thing I learnt from this is that the American distribution system is insane
*Unarguably true!*
I really like how this video simplifies the concepts because it makes it so incredibly easy to actually understand what's going on. I never really understood why AC has 0 in the middle, but it makes a lot of sense now that I know it's because the generator is pushing and pulling instead of just "generating" electricity.
9:24 Why 69K to 12.4K? That ratio (5.56:1) seems "unnatural". (I wondered the same about the 230K to 69K drop, but that ratio is 3.333:1, which is "natural".)
Very nice video. I would comment on 3 phases in a "standard" home. I live in the central Europe and generally, at least nearby big cities, we do have 3-phase connections. I'd say it's a must for new installations because we need more and more power. One typical appliance that requires at least 2 phases is an induction cooking plate. And if you're a DIY hobbyist, there's plenty of 3-phase machines targeted at home/garage shop customers.
So, in general, having 3-phase power at home is a nice thing
If you came for the title (which is “How 3 Phase Power works: why 3 phases?”), the answer for that is given in a single sentence in the mid of the video, without fully explaining. It explains what happens if you increase the phases, but doesn't discuss what happen if you decrease it and do not answer “why 3 phases” directly.
3 phases is the number of phases which was found to deliver the most power to devices without having to engineer in safeguards to keep the system viable. No one has demonstrated that adding more phases is economical and safe.
agreed, ive been scrubbing through looking for the "why not 2" and im not really seeing it. And in the comments, i learned it's because a Harley motor shakes a lot :shrug:
Mikhail Dolivo-Dobrovolsky invented 3 phase generator , 3 phase transformer and induction motor , in Germany 1890s.
Same time in Sweden, Jonas Wenström received in 1890 a Swedish patent for same 3 phase system, that was start of ASEA, that is now part of ABB.
Nikola Tesla in USA and John Hopkinson in UK, also came in conclusion that 3 phase system had something.
So you had 4 men in 4 different countries that all came to same end result, 3 phase AC system, with practical experiments.
I worked on a system that used 9 phases, 200v, roughly 1000hz per phase.
Multiple reasons for 3 phase are listed throughout the video, here are some key points
4:30 Explained how 3 phases provide constant power. Graphic shows “almost” and audio says “more constant” with some small ripple shown, at this point all phases are still separate circuits and we have built upon simple single, two and then three phase generator.
5:05 Explained how it provides equal spacing.
5:36 Explained how more phases means more cables, controls and protection equipment, complex infrastructure, more complex transformers and motors, harder to balance network and synchronise generators.
6:22 Explains how only 3 wires are needed which is cheaper.
7:26 Explained how neutral can be used to balance
7:54 Explained how we use single or three phase from same system
8:21 Explained how Wye and Delta are used for different scenarios. Examples uses same resistance and line voltage.
9:59 Explained how 3 phase allows more loads to be connected
10:17 Explained how 3 phase uses more energy but provides more heat
10:19 Compares single and 3 phase power, shows 3 phase power is consistent
10:36 Shows single phase and 3 phase motor. Single phase has capacitor
10:41 Shows comparison for 3 people v 1 person for motor analogy.
Retired physics teacher here. Most impressed with the brevity and simplicity of your descriptions.
6:00 bonus points to Japan for designing two incompatible networks linked with a massive AC-DC-AC interconnect 😅
This video is so good at compressing various Electricity and Magnetism lectures into a single 15 minute video.
Today I learnt that the letter Y is spelt Wye 😆
Excellent. Summed up in 14 minutes about half of the 1st year of a BTEC diploma in EE. Great job Paul!
It's also important in distribution that in European countries a transformer can feed tens of houses, sometimes hundreds, multiple streets and the secondary side is also fused unlike in North America.
The American one looks crazy, so may different voltages.
This is sort of wrong. Usually you have 1 substation (lets say it steps it down from the big transmission lines to 1200V) feeding a town of anywhere from 10,000-20,000. From there it it gets further stepped down on the pole to 120/240 split single phase as most of the grid is designed to be residential load based. Transformers are spaced out every 5-6 poles as step-up transformers to try and keep the secondaries on the poles at a constant voltage. Also the primary sides of the transformers on the poles are fused. In the event of a short or overload on the secondaries of the pole transformers, the utility expects the transformer to blowup as the fuse which in turn would blow the primary side fuse (though this does take a big short/overcurrent and time to cause). Also most substations are equipped with circuit breakers in the event the secondaires out of the substation were to short out. In terms of a Commercial application, the building gets its own transformer as seen in this video due to its needed a 3-phase hookup of either 120/208 or 480/277 depending on the loads the space needs (also the video does fail to show that 277V lighting is a thing). The only time a house would get its own transformer is for one of 2 reasons. The first reason is that is a higher amperage house than normal (higher than 200-300 AMPS). This results in the utility either giving the house its own transformer on the pole or having a transformer installed on the persons property. The other reason occurs when you get to the low population density areas where houses are easily a .25mile to .5mile apart and it is not feasible to have a step-up transformer every 5-6 poles.
This educational video is a gem. I've learnt this kind of stuff on a theoretical basis back in school but your way of visualising makes it all quite easy to understand. Well done.
So, two phases aren't as efficient but four phases are too much! 😆
Who knew Goldilocks was an electrical engineer?
@@eyerollthereforeiam1709 Maybe she was just going through a phase...
@@PunmasterSTP GROAN! You truly deserve your screen name.
@@eyerollthereforeiam1709 Just let me know if you ever want to hear a pun on a particular topic 👍
there are a lot of amazing things in this video but wow that might be the best explanation of RMS I've ever seen
Why 3? Is because is a reasonable number, could have been anything, but less than 3 makes motors lose power during the deeps, more phases is just too much.
Not really, it wasn't an arbitrary choice. 3 is the minimum number of phases to supply constant power to a passive load (e.g. motor or heater). Any multiple of 3 (6, 9. 12-phase!) would do the same but going to 6 or 9 phases would give no advantage.
@@snarfsnarfs That's what I said... BTW, 3 phases do not supply constant power, the power still drops, but not that much to cause instabilities in mechanical outputs.
@@gabrielbarrantes6946 in an ideal system the power doesn't drop at all. It is constant power all the way through the cycle.
As the instantaneous power from the 1st phase starts to drop, the other 2 phases start to deliver that power in the exact proportion that the sum total stays constant.
For circuits containing active components it's different, but for passives like motors/heaters/etc the sum total stays constant through the cycle.
@@snarfsnarfs 2 phases shifted by 90° also show constant power. But then you need 4 wires (two separate phases) or 3 wires (one common to both phases). The current in the common wire is sqrt(2) higher, so a thicker wire is needed. But if you need 3 wires anyway, a three phase system is the optimal solution. as then the current in the common wire is zero and this wire can be omitted. Anyway: you are perfectly right: power is constant in an ideal system, while in the video is said: in an ideal system power still varies a little.
@@RainerNase-b3q That's a really good point. 😀
In the 3phase case we have:
p1+p2+p3 = sin^2(x) + sin^2(x + 2×π/3) + sin^2(x - 2×π/3) = 1.5
In the 2phase case it's also constant as you said:
p1+p2 = sin^2(x) + sin^2(x + π/2) = 1
I never really thought of it like that before. As you said it still ends up requiring an extra wire (or a thicker common wire) than the 3ph case anyway.
Thanks for raising the interesting point. 😀
As electrician I always knew these stuffs in theory,, now for the first time I have it visualized in my head and everything is now complete.Thank you!
In Greece all homes have 3 phase.
LOL, no...
I absolutely agree that your explanations are EXCELLENT, clear, concise and simple, you have clarified why we use 3 phase, why we step up the voltage on transmission lines and the differences between 3 and single phase star or Delta etc. ....as an electronics hobbyist of over 50 years one question still escapes me though..... why, here in the UK for example did we settle on 50Hz, why do some countries use 60Hz and why not use, say, 100 or 200 Hz etc which would surely be more efficient.....
Thankyou!! This one part i didn't understand in physics.. now i understand the entirety of Ac
At 2:06 the oscilloscope is 90 degrees out of phase. If this is meant to be an educational video you should get details like this correct.
I have literally no experience in this, but I’m curious as to why it would be out of phase there. The highlighted area under the curve shows the wave to be at 0 when the magnet is parallel to the coil. Would that not be the case? From someone with no experience that seems correct, but If it’s wrong I’d be interested to know why.
Relax bud. This isn't a video on how to read oscilloscopes. Also, you're holding your phone sideways so you're 90 degrees out of phase
@@nickdowning5562it's not off phase. When the negative is facing the coils the dot should hit the peak of the negative wave
@@AfricanLionBat it is wrong, because the stator windings are drawn in the wrong orientation
Or the magnet is wrong paited
Excellent tutorial. If these concepts were taught in schools this way then more people would be interested in the various electrical tradecrafts. You answered questions that have been lingering in my brain for the last 40 years while working as a tech in plant maintenance. Direct Current is easy and straight forward. Alternating Current is more complicated but you have done an outstanding job with illustrating the concepts and simplifying the alleged mysteries. Well done. I'm subscribing. (i.e. I always wondered the reasons why Delta and Wye were used in 3 phase circuits)
incredible ! this video makes me understand 3-phase electrical more than what my teacher taught me . Thank you a lot, man.
Very well done, thank you! 3-phase is the biggest bang for the customer's buck, with only 3 wires, only one additional wire compared to single phase. For some high power machines, 5-phase is better, although more costly (but less ripple and conductor size is reduced). Both 4-phase and 6-phase are basically useless for motors, the increased cost gains you nothing over 3-phase and 5-phase respectively. However 6-phase is a nice low-cost solution for so-called "rectifier front ends" converting to DC with very low ripple, and is easy to implement with the right transformer connections. This is the best video I've seen on the topic.
I think this is one of the best explanation of the RMS value I have ever seen. Good job
I lost it when the electrical worker walked away from the global power standards! I've felt that way for decades.
Thank you. Your explanation of 3 phase was the best I've seen .
A valuable video explaining three-phase current. Many people think it is just one current (going by the name). I think coils in the stator of the generator are positioned radially from the center, and not along the circumference, for better magnetic field penetration/change. This is demonstrated at 1:10 into the video.
I liked the infographic of single vs. 3 phase motors, depicting one person trying the crank vs. 3 people passing the crank.
In north America, the secondary 120/240 is referred to as "split phase", as phase to neutral provides half of the phase to phase single phase wave voltage by tapping the transformer in the middle.
Glad you liked it. We did show a very nice graphic for split phase in out last video also fyi, link here ua-cam.com/video/u0SsejDCVkU/v-deo.html
Electrical Engineering used to be one of my favorite subjects while pursuing Computer Science engineering. And for some reason I felt an itch to revisit the concept of phases. And I'm glad I came across this channel. Definitely explained better than my college professor 😅
Awesome explanation, thanks. I knew the generator magnet spun in a circle and 360/3 is 120 degrees per phase, but I didn’t know how those phases overlapped in terms of the currents.
as an CS engineer guy i love this video. i had few EEE courses that i had struggled very much. but now this looks very beautiful.
This tutorial showed up just when I needed it. I was recently looking at some high voltage lines in the area and wondering why there were three wires. But before I got around to trying to look it up your video showed up and answered the question for me. Thanks for the great explanation of 3 phase power.
Many thanks. As a chemical Engineer, I really enjoy this channel. Specially when it comes to energy and electricity subjects.
9:06 It's worth mentioning that the reason high voltage is used is because the loss in the wires is given by (Current squared x Resistance of wires). So halve the current by doubling the voltage (for a given wattage of power delivered) then you quarter the losses. This permits the use of relatively modestly sized transmission cables, when you consider the power they are delivering. Very high voltage means fairly low current flow and yet still a good power delivery. The upper limit being, how to insulate very high voltages on the lines and make safe and effective transformers to step up and down and the ends.
This video is way clearer than the classes i had during my mechanical engineering degree. I really wish i would’ve seen this 3 years ago
As a mechanical Engineer, this taught me more than my few intro EE courses ever did. But now I want to know more, let the deep dive begin.
Nice explanation! Except for the RMS part, that honestly shocked me a bit - it's certainly not just that "someone realized" heat production in a resistor and experimentally figured out the ratio approximating sqrt(2), you can really calculate that knowing that P = U*I = U²/R (which, yes, "someone" realized at some point), calculating the average power noticing that sin² averages to half the (squared) peak and taking the square root of 1/2 to obtain exactly the sqrt(2)
Well said. I think😂
Awesome video to give me the starting point of understanding 3 phases. One thing I didn't understand is why not use less phases, like 2 phases
This was great, I need 3-phase explained to me like every few months. We indeed have 3-phase residentially in my part of the world, used for storage heaters, and some old ovens, but mostly unnecessary. This explanation simplifies nicely what I have to do to convert a 3-phase socket to single-phase - just connect neutral and one of the phases.
Deutschland?
@@onradioactivewaves Serbia, but yes, we are heavily influenced by German technical standards and terminology :)
I heard about these 120 degree offsets in so many videos, but FINALLY someone explains what it really means. THANK YOU! :)
So clear to this amateur handyman. Now I just want another video explaining the first principles of Neutral.
You did better in explaining delta vs wye is a couple of minutes than a whole semester of Power Generation class!