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This video is awesome. Great knowledge on utility transformers. Please keep making videos. Such as capacitor banks and underground apparatuses. Etc thank you.
@@EngineeringMindset Thank you for replying. I use your videos to help me explain transformation and theory to apprentices. Great stuff. Plus they can hear and see what I am trying to convey in written Text. I would like to see an animated version for vectoring and the displacements. My drafting and animation are zero. Keep up the great content.
The algorithm suggested this video? I am a retired electrician. 35 years commercial, industrial and Institutional. This lesson brought me back all those years to the beginning. I had a great teacher. He used similar illustrations except it was using an overhead projector. It's very rare that I watch anything to do with my former life. This was some good fun. You did a great job. Thanks.
Retired EE here, same for me. Never specialized in construction so I intermittently needed to work on the many configurations used in manufacturing plants. It was a good career, usually, lol.
I am an Electrical Engineer graduated in 2020 I find your videos very helpful for my MEP Construction Job and understanding the National Electrical Code and Electrical theory.
Little tip from someone on the electric utility side to the MEP engineer (I interned at an MEP firm): It’s super important for you to balance the loads in the building. When we’re looking at 3-phase transformers on the grid we always assume balanced loading on them. If you unbalance them enough, especially for larger transformers, it can really screw things up because our load models won’t match reality.
@@numbah_6 thanks for the tip I only done a little of lighting and power design for 3 phase panels my day and day is working as a construction manager monitor the work progress of new construction of buildings in NYC . In terms of transformers mostly see dry type transformers as large as 1000 KVA in the Switchgear room
Nice. Yea I have been E for MEP for a year and I deal with xfmrs every day. This is a great explanation. We refuse to send out new projects without a 10% or lower load balancing across phases.
I’m showing all my substation interns this video to help them understand the madness behind electricity. ⚡️ As a PE working in substation engineering, I wish I had videos like this when I started 10 years ago. I truly appreciate your gift to teach. 🤝
Working in electrical distribution. Realized a lot of people don’t understand how this stuff works (electrical distributors), and wasn’t satisfied with the explanations I was getting for how electricity worked. Started watching your videos and the stronger understanding you have given me got me promoted to industrial electrical sales. Best electrical channel on UA-cam hands down.
@@EngineeringMindset Show you to all my coworkers who need help with understanding something. My words cant communicate the ideas the same as your visualizations. I had to go to a training on motor controls and they ended up showing some of your videos for a visual explanation on how everything worked. Funny because thats how I learned about electrical motors in the first place.
Just wanted to say I really appreciated how you re-orient some of the diagrams that position the schematic how it would be sitting in a physical transformer...as someone who is just curious "how stuff works" this is something I've never been able to wrap my head around you could have separate transformers doing 3 phase power even though I've seen the "triangle and Y" positioned diagrams countless times I just couldn't wrap my head around how it was possible until I saw your diagrams MOVE in the video and something finally clicked how the "real world position" would be vs the "diagrams" you see all the time! That was great!
I have looked at transformer diagrams for years and never quite understood them. But when was gazing at the diagram at 0:22 and imaging it in 3D suddenly it all came together at once. Great job! Subscribed.
Ok. Ok. I understand that this might be more information than most people even care to know about how electricity (like the stuff that powers your home and, well, life) works, but I found this single video to be just about the best crash course on the subject that I've ever seen. He's managed to condense an entire college course of material into one video. Blew my mind at how well he did this. Also, don't let the British accent throw you. He's explaining the USA power grid.
I saved the video Becuase from time to time over the years this discussion comes up amongst my circle. Purely from a need to power a piece of equipment, and what’s the best way to achieve it and get the machine running. Many people understand these concepts in different ways, a friend of mine is a commercial elec chicken, and he just rolls his eyes when this discussion starts up.
I’m a mechanical engineer and got an electrical engineering job for my city because they couldn’t find qualified applicants and I needed to work. This helps a ton and helps me learn!
Hey! I'm a mechanical engineering working with semiconductor manufacturing equipment. I've been learning signal transmission theories and standards on the fly since I do more electrical engineering than my major taught me.
Some interesting things about 3phase transformer connections. Delta - Y is usually preferred. Thats because 3rd harmonics don't get transmitted back into the incoming line. A zig-zag transformer can be used to create a central ground for delta connections, but that is only used for special industrial settings, at least to the best of my knowledge. In the US, Delta high leg and open delta are becoming obsolete. They were an out growth of the split phase systems used in residential power configurations. They are usually not installed in new service systems anymore. The vast majority of operating ones are legacy connections.
Yeah I have an open delta now and I'm in NE Pa. but I really don't see many others around up here. I'm originally from the Philadelphia area and they were really common there but I don't know if you can still get one from PECO. I know PP&L doesn't offer them any more, only the 208/120 wye. In Philly we also had quite a bit of 120/240 two phase even though all the distribution is three phase now so they have to be supplied by a Scott-T.
@@joecummings1260 2 phase quadrature? I thought those were completely gone, but you're saying Philly still has quite a few still running. That's interesting.
@@VTdarkangel Yeah quite a few of those services down there. about 15 years ago I worked on a 600KW three phase generator that connected to a Scott T and then to an almost new 2 phase transfer switch that must have been a special order and cost a fortune. That was at the Youth Study Center (kid's jail). Supposed to be a lot of two phase office and retail in center city. City Hall had it at one time, but as far as I know it's all three phase now. Lots of the old equipment in the basement abandoned. There is even some abandoned DC equipment down there probably installed in the 1800's. Bridesburg, fishtown and port richmond has a lot of 5 wire ariel drops yet. It's slowly been getting changed though because two phase equipment is impossible to find, and most of the rewind shops have closed
@joecummings1260 The only 2 phase load in my area that I know of was shutdown about 10 years ago. Actually, it burned down, but they elected not rebuild it. I figured there were more out there, but I figured they were few and far between.
Delta high leg is still quite common in my neck of the woods. Much simpler if you've got a lot of mechanical loads, want less than 250V to ground and a much smaller amount of 120V loads. Residential transformers can be used in this way, and reduces the total number of different transformers used in a power delivery system.
As a retired Dutch engineer, working with single fase and three fase only, without any half tap at 120 Vac, this video finally explains how it works in the US. Thank you very much.
In 2005 when my mother remarried and moved to my stepfather's farm, we had an open delta 3 phsse, because we had a grain dryer, conveyer and large auger with 3 phase motors, with the majority of our loads being 120/240 single phase, transformers on the roadway, pole with meter and site disconnect in the middle of barnyard, single phase ran to house, 3 phase to barn, where there was a 3 phase panel dedicated for the motors, also feeding a single phase panel beside it for the other loads. Otherwise roughly 1/3 of the panel slots would be wasted because the B phase (high leg) is unsuitable for single phase loads, which is a major disadvantage of a 4 wire delta service and thus the 208Y/120 & 480Y/277 (or 600Y/347, if you happen to be in Canada or a few areas in the US) is a much more common and useful configuration. Open delta is still fairly common on some farms and small commercial buildings where the customer has mostly single phase loads, while also requiring limited amounts of 3 phase power, since it's cheaper to set up than a wye bank.
This might be a bit dense for a total newbie, but I'm finding it a wonderfully efficient, clear, and comprehensive refresher that really brings together the substance of multiple other longer sub-topic videos.
Thanks for the breakdown. As an electrician for 14 years, I've always wanted to know how the different configurations of delta/wye affect voltage/current output. The most intriguing thing is the ungrounded delta primary which gives uncommon voltages to ground. Very cool....
Audio engineer here, this is super super useful to my field as well. Knowing power is super important when tapping into these commercial feeders, knowing this kind of stuff will get me paid more. Cheers!
Very nicely done. I earned my BSEE from NorthEastern in 1991. I used pencil, paper and calculators back then to study, study, study and learn this material. This video explains the physics behind transformer and power transmission technology very simply and clearly.
Funny enough, the switch from solid block cores to plate stack cores wasn't because of eddy current losses, although it was a nice bonus. It's mainly because it's cheaper to stamp out a bunch of steel plates and stack them, rather than milling out the shape of the block.
I find this quite useful and at least interesting even as non electrician. I highly recommend watching the video 3 times and take notes. This is an entire year of schooling packed into a 24min UA-cam video afterall. What strikes me the most, is how EVERYTHING is arranged and explained, starting with a large envelope and then going right down to the small parts and the physics that make it all work. Very well put together!
I just want to say big Thank you for your videos. I am in an electrical apprenticeship and these videos are really helpful with understanding how these equipment and thoery works. Ever since i started watching your channel i have become better at trouble shooting and overall a better electrician! THANK YOU!!!
This brings back memories of Army Corps of Engineering for 52D power generation school. Why I never pursued this in civilian life is beyond me, because it was so fascinating and practical. I was the honor grad in 1988 probably because I really loved power and electrical systems, as well as trigonometry.Synchronize your generators and create your own power grid!
I was an electrician for many years and I think this video will inform those who have no idea how electricity works. Basics are an essential element to understanding. I am also an amateur radio operator and appreciate someone instructing those who have an interest in such material.
I'm in an apprenticeship, in the commercial and industrial end. This is fantastic, I've watched several of your other videos. They're very easy to take in, you have a gift, my friend I thank you for your contributions.
I'm guessing that wasn't a mistake so much as ... "ehh.. not really, but uh... we'll get to that later." And, TBF, at the end, the voltages were marked as RMS. RMS was one of the hardest things for me to wrap my head around, so I don't hold it against anyone to gloss over that for the sake of illustration.
Great video, I like how you always go much more in depth than I expect while still keeping it simple to understand with some basic knowledge. Best channel in this niche IMO
As an electrical engineering student, your content has been helpful for my entire career (including this one) and this video is no exception, thank you for all that you do!
Thank you for this video. So detailed and easy to understand. Goes step by step and doesn't go backwards, but rather it references what you learned earlier in the video and applies to the current topic.
I liked the entire video honestly. I have been using it to help teach my technicians what 3 phase is and how it works. Your videos are very informative and well made. Your content is a valuable teaching aid in my industry.
Excellent. I’m an electrician that is trying to increase his knowledge at a very late in life age. Some videos put me to sleep quickly. Yours are interesting. Thanks
I use Maddox Step-Up/Boosting and Step Down/Bucking Transformers at work in both low and high KVA applications. I recently used a 208v Wye Secondary as a primary and stepped up to 480v Δ as secondary. I called the transformer company first to make sure this was allowable. It was and I have no issues. Maddox is a very knowledgeable company to work with and have great people on staff to answer any questions about their products and have many transformers in stock.
Videos can be helpful for apprentices, but as a 35 year electrical contractor I wouldn’t use it to train them. Classroom works best. In my State it takes 10,000 practical hours and minimum 4 years of night school to get your General journeyman card. Back in the 1990s when I was getting my journeyman card we didn’t have UA-cam but we did have well researched videos from the IBEW.
Excellent tutorial. The one item worth expanding on is the phase shift from a wye-delta (or delta-wye) transformer and how that could be exploited to get an even more constant power output (a follow-on from @3:20 in your video). If you use both a wye-wye (no phase shift) and a wye-delta (phase shifted) transformer pair the output power would be more constant. With rectifiers on the output, this combination is sometimes used to provide a close approximation of smooth DC power for some subway systems. This is also used with an additional inverter on the output to run induction furnaces.
As a new Substation Engineer with a degree in Computer Engineering, this video is perfect since I am studying for my FE and I come from a background where Power is not covered. I will recommend this video to my new grads at work! Awesome work!
Funny how different it is in various countries. In Poland, for instance, majority of households (at least not flats, but freestanding buildings) uses 3-phases split from 400V.
Every apartment in Sweden has 400V 3-phase without exception. The big advantage is that you can use much smaller cable area and other equipment such as switches can also be made smaller and cheaper due to lower currents.
@@smolboyt >>sometimes it's still 220/380 in old networks. Yes. According GOST 29322-2014 voltage should be 230/400 +/- 10% . So old voltage 220/380 in old networks is still "normal" according GOST. Meanwhile new networks works with 230/400.
Oh this video definitely only applies to the US grid. Hence why he even showed 240 Volt split phase, which is pretty much only used in the US and Canada.
Yeah, it annoys me when American channels have British narrators because it takes me longer to figure out they are talking about the US, interesting video all the same but their power set up is nothing like Europe's.
Excellent work. Most of these videos stop at kindergarten level. I remember being thoroughly confused the first time I encountered a high leg delta. Superficial knowledge of the theory without fundamentals is good for trivia night and useless in a dark sub-basement with a multimeter that's telling you that you don't know what you're doing. Thanks for going through the trig; the math is really straightforward once you actually start paying attention and working it out properly.
The different aspects of xfmrs covered is amazing, as well as, the clear narration. However, I would have to say the part of the video that really drives it home is the visuals and animation. They make it so easy to follow and understand.
Top explanations, thank-you. I was not familiar with "high leg delta", I have never come across it here in the UK. I was however aware of the 60hz USA vs 50Hz Europe. The centre tapped 120V domestic mains is a US thing too. In the UK we just get neutral and a 240V line.
This video is incredibly creative and informative! The way it explains the three-phase concept is both clear and engaging. The most enjoyable part was that I finally understand how three-phase works, thanks to the excellent visualizations. Great job!
Fantastic video, but to explain the ground in the y configuration you could also explain the cases of simmetric and balanced where current and voltage have the same module and phase shift of 120 degrees therefore in the central node the sum of the 3 currents is 0 so as to obtain the return of the neutral
This is hands down the very best channel on UA-cam BY FAR. you have taught me and the rest of us so much. So very very grateful for the engineering mindset. You've turned me into a total nerd and I LOVE IT!!
For most places/purposes 120/240 distribution beats 120/208 distribution. The extra 12 folks will keep motors happier. Three phase is a PITA to actually use directly on motors. It often requires protection again phase reversal. If a smaller customers decides he wants 3 phase motors, today the best solution is that put in a VFD (Variable Frequency Drive) and provide motors with the most efficient voltage ans power.
I do not go into splitfase as we have 230/400, all our grid is 3 fase from producer to home. Most of our grid except a small part of 10kv and 60kv (60-150-400kv are airborn usually) is plowed down in the ground, and it will create less blackouts in adverse weather. All these different voltages and conversions, 120-208-240-277-480, 230/400 50hz is all we need in 90% of cases.
An excellent tutorial. Reminded me of the one "power" class I had in Electrical Engineering where we had to learn all this stuff and do Delta-Wye transforms, which I have never used since....:) Not much demand for power engineering in microprocessor development. But, we had a great time in the lab hooking up 3 phase motors to another 3 phase motor run as a generator. Didn't want to connect the phases wrong or the "generator" would just around on the test bench. What I really appreciate is the explanation of the various configurations and transforms to get from 3 phase to single phase residential. It's often hard to explain to people why industrial drops are so different than residential drops. I am forever grateful that we standardized on 120V in the US because I had to work on 240V systems in Europe and it always seemed lots more dangerous.
Where I'm from reversing any two wires on a three phase motor just makes it run backwards. Of course you want to be careful if whatever the motor is turning doesn't like spinning backwards, otherwise it doesn't matter. What is "justing" around on a bench mean? Also, where I'm from, you can run a three phase motor on single phase, plus some extra stuff to get it started spinning, then generate almost real three phase power from it. So, if you've got industrial manufacturing equipment in your garage at home, you can still run it at reduced capacity...
This is amazing stuff. I have a BSEE with a focus in power systems and this basically condensed a years worth of upper division EE courses into a beautifully illustrated and easy to understand video. I wish I had resources like this when I was in school. Fantastic work!
I really like your videos! There isn't another UA-cam channel that does explain electrical engineering as you do! CHEERS. Also, do you mind making videos about smart grids, dynamics and stability, or HVDC topics? I am currently doing an MSc in Power Engineering in ICL and I find those topics quite interesting to promote Electrical Engineering to fellow students.
The US electrical system is so complicated. We do have local transformers for each collection of houses. I live in the countryside in Sweden. We have 3 houses with property lines next to each other with a fourth a few hundred meters furter down our road. We have a transformer split between us and all houses, get their own 400V 3-phase cable to our meter box, and from there goes 3-phase into the house where it's split into three single phase 230V. No extra split phase like you have, and only two voltages to keep track of. Commercial buildings can get their own high voltage connection, which is anything above 1000V, but that is only if your industry need more then 0.5 MW of power or they recommend that you keep to the normal 3-phase 400V since it's most likley to expensive to get if you not have need of it. The nearest town also only has one transformer for the whole town, but that is a bit bigger than the one we have. That one even has three fly wheels to stabilise the load, which bigger transformers have sometimes. Almost all the grid here is underground as well. They dug down the cables a couple of years back since it needed to be replaced anyway because of the age of the air cables and we had much problem with power outages during storms and such and almost none since then.
Thats how it works in America on the residential side in the suburbs. Usually you have 5-6 houses on 1 split phase transformer that is fed from a local substation, might be a 3 phase if the grid you are connected too is old enough especially right outside of NYC. The only time you usually get 1 transformer to a house is in the rural areas where the houses are more spaced out.
I'm a mechanic learning a bit of electrical over the years. Was good up to about the 9 min mark. Will have to come back and rewatch when my attention span and cognizance returns 😂 Excellent explanation and video so far and thank you!
In Europe we have 230/400V and easier installation. There are also some different voltages like 690V or 500, but mostly is 230/400V. And I's used for all applications - home, industry.
and it was partially due to lack of material for wires after WW2, as higher voltage required small gauges and less copper. In the US there was no shortage of materials
This video is why in Europe we mainly just have one type of transformer. Everyone except heavy industry etc use 220 -240 VAC so none of the delta or wye nonsense. Just imagine, not just the less maths but the fewer spare parts to carry to fix the damages. Also, because of standardization hopefully cheaper products. Higher voltage finally means a greater margin to serve. As for safety, even 12vdc can kill you under the right conditions. Notice the term "right conditions" and avoid it at any cost.
12V would take very VERY extreme conditions to kill someone. V=IR. It takes about 0.1A to kill someone. With 12V the human body would need a resistance of 120 ohms to be at that lethal mark, or the current would need to be sustained for a long time. For reference, a soaking wet person is around 1kΩ... Would take closer to like 40V to get dangerous. Really we are talking about energy here though. It isn't volts, it isn't amps, it's the combination of the two over a period of time. Factor in volts, amps, timeframe, and path of travel before saying anything is lethal or nonlethal
This is such a good explainer video - I wish this type of material was available back during my college days. Electrical engineering teachers need to be showing this vid in their classes (and the school then donating to the creator).
Great video! I got a clear understanding of Delt and Wye configurations and how to perform basic calculations. I downloaded the 3Ph Transformer Basic Cals pdf, and helping it to stick even more.
Very happy to see your phase explanation as many electricians refer to the two 120 VAC lines in your house as phases. This is incorrect as you properly explain.
Finally a video i cannot watch in 2x. And need to rewatch at least once. Can someone explain why the resistance scales with amperage but not so much with voltage? Why do some countries build higher highvoltage cables than others? I forget the formulas
good video explains the US system nicely. The only thing that was disorientating in the beginning was a british person narrating about a 120v 60 hz US system. in most countries that use 230/240v 50hz (talking for domestic not heavy industry) the feeder is 11KV 3 wire 3 phase that goes into large delta to wYe PMT ( located in a neighbourhood) stepped down to the 415v 4 wire 3 Phase (l1,l2,l3 N) from where you get 3 legs of 240v single phase L N. Large homes and building get the 3 phase 415v connection, small homes, apartments get just one phase. with 3 phase supply the neutral return wire can be the same size as one hot line as currents cancels each other out because of the phase difference etc.
0:22 In Europe the output is always a Y configuration. The voltage is 220 to 240 volts to ground. Or from phase to phase 380 to 420v. Often referred to as 230/400V...... 230* SQR(3)=400 V Rarely there is 230V from phase to phase (and 127V from phase to ground). The domestic sockets are connected to 220 to 240V 50Hz. Mostly 230V 50Hz
Typical voltages in Germany: High voltage: 380kV, 220kV, 110kV. Medium voltage 20kV, 10kV. All 3 wires. Voltage for consumption: 400V 230V AC 3 wires + neutral wire. Sometimes extra wire for street lighting. Electricity for train: 15kV overhead line or 110kV 2 wire for transport.
At 11:03 it took me a while to reason why the sqrt(3) is in the denominator for secondary outgoing power from each coil, rather than the top. Then I remembered that 3/sqrt(3) is sqrt(3). There are three coils and you're calculating power per coil, so the 3/sqrt(3) is simplified to sqrt(3).
So what makes design engineers choose one transformer configuration over another? Type of equipment and demand on client side is all i can think of? Why would you want a delta vs a Y on secondary? If voltages are the same? Are there benefits/drawbacks to have Y as secondary for neutral safety?
The Delta and Wye transformers are not the same output voltage. I worked at a place that had 480 volt service to the building, and they had a 208 volt wye transformer on the roof to feed several Mitsubishi three phase 208/230 volt heat pumps on the roof. They had dual input voltage ability, and they could take in 208 volts at 125 amps or 230 volts at 100 amps MCA. (actually 124 MCA at 208 volts and 93.5 MCA at 230 volts.). So if they had known what a Delta transformer is, they could have picked a smaller delta transformer, and fed the units with 100 amp breakers and 100 amp disconnects, #2 wire instead of #1 wire, and saved money. The cost difference between a 100 amp three phase outdoor disconnect and a 200 amp is a lot of money! They did not need to run any of the 120 volt circuits from this transformer, and do not need to put in a neutral wire, only a ground in a Delta system. Overall cost savings is smaller wire size, the 100 amp disconnect instead of 200 amp, and circuit breaker cost. The higher voltage (240 volts VS 208 volts) means that each motor will have less amperage going through it, so less heat loss, and less voltage loss due to lower amperage. With the normal 208 volt wye transformer, the main advantage is you can also get 120 volt circuits from it easy. So had this transformer needed to run 120 volt circuits, then a wye transformer would be more a requirement. But this was only running the rooftop HVAC systems, not the 120 volt systems inside the building, that had other transformers.
Wow, you made this very fun, My later Father was a master Electrician, and I have a HAR/V . It a very technical field, and takes a lot of mental work to understand it. Sad that most young people here in America, do not like math and science, because our great nation is built on this area of science and physic .
Any chance you could follow this up with pros and cons of each system and give examples of why they are selected? And has the selection been changing because of the reduced need for 277V lighting (moving to 120V LED)? And include thoughts for other upcoming changes (maybe to accommodate energy storage systems}? Thanks, as always, for the excellent content!
Hi, If the building was built with a 277 volt lighting system, then changes from fluorescent to LED lights, they are not going to switch the wiring to 120 volts, it is just to expensive. Also the 277 volt lights can put 3,500 watts on each 20 amp circuit breaker, so a lot less wiring is needed for a large building. The maximum possible load on a 20 amp 277 volt circuit is 16 amps or about 4,400 watts. A 120 volt circuit at 16 amps is a maximum possible 1,900 watts. Most are limited to only about 1,800 watts. What the electricians did at one place I worked at, they had a conversion LED lamp, 4 foot long, and if they already had a electronic fluorescent lamp ballast, they would install the LED lamps, and they worked just fine on much less amperage. However the older magnetic ballast would have to be replaced to use the LED lamps. Most of our buildings used 120/208 lighting systems, not the 277 volts, only 3 buildings had 277 volt lights.
Beautiful video, now I would ask something.... If I bring an european appliance designed for 240 V ( line and neutral) and connect it in US to 240 V- 2 phases will it work fine ?
if it's the 240v single phase split phase then it can work but there's the 60hz problem: if the device says 50/60hz then it'll work just fine if the 50hz device has a motor then it may not work properly or even break if the 50hz device is an ac/dc adapter like an rvl-002(eur), rvl-002(ukv) or rvl-002(aus) then it'll likely still work with 60hz
My brother brought back some 240 volt appliances from Germany, including a vacuum cleaner. They all worked fine on 240 volts in America. They had a refrigerator, and some other appliances. They did not bring the stove. In Germany, when you rent a apartment, it does not include the kitchen cabinets and appliances. If you want to buy them from the tenant that is leaving, you can do that, or they might take them with them to the next place. My brother was offered a small amount for his cabinets, so he had them put on a cargo container headed to America, paid for by his boss when transferred to America. It actually cost him a lot of money go get a couple of additional German cabinets when installing them in his new American home, with a larger kitchen.
This video has answered a question that's been bothering me for a long time: when I use a Public Level 2 EVSE to charge my car, I only get 208 volts/32 amps (6,600 watts), whereas when I use my own EVSE at home, I get 240 volts/32 amps (7,680 watts). Public chargers always take 45 minutes longer than my home EVSE to charge my car, and now I know why! Public EVSE's, typically in shopping center parking lots, are apparently being fed off of 3-phase, 480 volt Y or Delta transformers that only supply 208 volts per phase, whereas the NEMA 14-50 outlet in my garage at home is being fed from a center-tap 240/120 transformer that gives me a full 240 volts across the two hot lines. A 3-phase transformer with 480 volts per phase, is wired to give 120 volts on the secondaries, between any 1 of the output phases and the neutral. All well and good for supplying 120 volt ac wall outlets and lighting systems. If you tap any two of the phase coils, which are 120° apart in phase angle, you will see that when 1 phase is peaking at 120 volts, the other phase has 88 volts, and the combined voltage at that moment is 208. In a residential transformer, the magnetic field of the single phase 480 volt primary feeds a secondary coil wound 2:1, yielding 240 volts across the full coil, or 120 volts across either end of the coil and the center tap. This leaves me with just 1 question: why would commercial buildings be okay with 208 volts for running high power equipment, when standard residential service is 240 volts, for powering an electric cooking range, electric water heater, and heat pump or a/c compressor? Especially when you are powering an electric motor, like an a/c compressor motor, I would think that a motor designed for 240 volts would maybe overheat, or run at the wrong speed, if fed only 208 volts? Why isn't all power service 240 volts for everyone?
Typically a step- up WYE Delta transformer is used between a generator and transmission line connected with the Generator connected to the Delta windings and the Transmission system connected to the WYE windings of the transformer . This provides isolation so a "Line to Ground "fault on the Transmission line cannot make its way back to the Generator as it see's it's "source "as the Transformer not the Generator. There will be a 30 degree electrical displacement ( or shift)between a WYE / Delta transformer primary /secondary winding voltages . Another fun fact with a 3 Phase Delta transformer is if you lose power to one input phase it can still produce 3 phase voltages at a reduced capacity of 40% . From what I read years ago was that this is why they used this configuration for critical facilities such as Hospitals for more reliability .
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This video is awesome. Great knowledge on utility transformers. Please keep making videos.
Such as capacitor banks and underground apparatuses. Etc thank you.
And as a@@PLEBEJones
Paul have you done any videos on vectoring? Did you create the graphics or do you have a software package?
No, haven't covered vectoring yet. All graphics are made and animated by hand.
@@EngineeringMindset Thank you for replying. I use your videos to help me explain transformation and theory to apprentices. Great stuff. Plus they can hear and see what I am trying to convey in written Text. I would like to see an animated version for vectoring and the displacements. My drafting and animation are zero. Keep up the great content.
The algorithm suggested this video?
I am a retired electrician. 35 years commercial, industrial and Institutional.
This lesson brought me back all those years to the beginning.
I had a great teacher. He used similar illustrations except it was using an overhead projector.
It's very rare that I watch anything to do with my former life.
This was some good fun.
You did a great job.
Thanks.
Retired EE here, same for me. Never specialized in construction so I intermittently needed to work on the many configurations used in manufacturing plants. It was a good career, usually, lol.
I am an Electrical Engineer graduated in 2020 I find your videos very helpful for my MEP Construction Job and understanding the National Electrical Code and Electrical theory.
Little tip from someone on the electric utility side to the MEP engineer (I interned at an MEP firm):
It’s super important for you to balance the loads in the building. When we’re looking at 3-phase transformers on the grid we always assume balanced loading on them. If you unbalance them enough, especially for larger transformers, it can really screw things up because our load models won’t match reality.
@@numbah_6 thanks for the tip I only done a little of lighting and power design for 3 phase panels my day and day is working as a construction manager monitor the work progress of new construction of buildings in NYC .
In terms of transformers mostly see dry type transformers as large as 1000 KVA in the Switchgear room
Nice. Yea I have been E for MEP for a year and I deal with xfmrs every day. This is a great explanation. We refuse to send out new projects without a 10% or lower load balancing across phases.
I went through a five year apprenticeship, with hundreds of hours of class time. This video clarified or brought a few new thoughts. Beautifully done
You have an electrical engineering degree and you need help with electrical theory?
I’m showing all my substation interns this video to help them understand the madness behind electricity. ⚡️ As a PE working in substation engineering, I wish I had videos like this when I started 10 years ago. I truly appreciate your gift to teach. 🤝
Working in electrical distribution. Realized a lot of people don’t understand how this stuff works (electrical distributors), and wasn’t satisfied with the explanations I was getting for how electricity worked. Started watching your videos and the stronger understanding you have given me got me promoted to industrial electrical sales. Best electrical channel on UA-cam hands down.
Very pleased to hear, and congratulations!
If you can help us help even more people by sharing links to our content, it would be much appreciated.
In all fairness, the smoke *is* magic.
@@EngineeringMindset Show you to all my coworkers who need help with understanding something. My words cant communicate the ideas the same as your visualizations. I had to go to a training on motor controls and they ended up showing some of your videos for a visual explanation on how everything worked. Funny because thats how I learned about electrical motors in the first place.
Just wanted to say I really appreciated how you re-orient some of the diagrams that position the schematic how it would be sitting in a physical transformer...as someone who is just curious "how stuff works" this is something I've never been able to wrap my head around you could have separate transformers doing 3 phase power even though I've seen the "triangle and Y" positioned diagrams countless times I just couldn't wrap my head around how it was possible until I saw your diagrams MOVE in the video and something finally clicked how the "real world position" would be vs the "diagrams" you see all the time! That was great!
I'm a 38 yr old Water Quality Tech learning about industrial pumps and HVAC.
Same thing for me.
I love the use of color to explain, also.
I have looked at transformer diagrams for years and never quite understood them. But when was gazing at the diagram at 0:22 and imaging it in 3D suddenly it all came together at once. Great job! Subscribed.
Ive been involved in the electrical trade off and on for 35 years. This is the BEST explanation ive seen. Very well done.
Ok. Ok. I understand that this might be more information than most people even care to know about how electricity (like the stuff that powers your home and, well, life) works, but I found this single video to be just about the best crash course on the subject that I've ever seen. He's managed to condense an entire college course of material into one video. Blew my mind at how well he did this.
Also, don't let the British accent throw you. He's explaining the USA power grid.
I saved the video Becuase from time to time over the years this discussion comes up amongst my circle.
Purely from a need to power a piece of equipment, and what’s the best way to achieve it and get the machine running.
Many people understand these concepts in different ways, a friend of mine is a commercial elec chicken, and he just rolls his eyes when this discussion starts up.
As a college grad in Electrical Engineering you guys won’t find anything better than this video. This is as good as it gets.
Agreed, @EngineeringMindset is amazing!
Agreed!
I learned this in 8th grade science class…. 😂
@ExecuteBrandon ....sure you did pal...
@@alienstorage1100 Some of us actually went to school where we learned things, not merely got indoctrinated.
I’m a mechanical engineer and got an electrical engineering job for my city because they couldn’t find qualified applicants and I needed to work. This helps a ton and helps me learn!
Wow, no offense, but that does not sound good at all!
@@chrisstromberg6527 not what I wanted but I couldn’t relocate and didn’t have my own vehicle
@@chrisstromberg6527 You’re right. But I’m not going to be doing this job forever, I’m just adaptable.
Which city is this ? Let it be known so we can send the best people out there 😅
Hey! I'm a mechanical engineering working with semiconductor manufacturing equipment. I've been learning signal transmission theories and standards on the fly since I do more electrical engineering than my major taught me.
Some interesting things about 3phase transformer connections.
Delta - Y is usually preferred. Thats because 3rd harmonics don't get transmitted back into the incoming line.
A zig-zag transformer can be used to create a central ground for delta connections, but that is only used for special industrial settings, at least to the best of my knowledge.
In the US, Delta high leg and open delta are becoming obsolete. They were an out growth of the split phase systems used in residential power configurations. They are usually not installed in new service systems anymore. The vast majority of operating ones are legacy connections.
Yeah I have an open delta now and I'm in NE Pa. but I really don't see many others around up here. I'm originally from the Philadelphia area and they were really common there but I don't know if you can still get one from PECO. I know PP&L doesn't offer them any more, only the 208/120 wye. In Philly we also had quite a bit of 120/240 two phase even though all the distribution is three phase now so they have to be supplied by a Scott-T.
@@joecummings1260 2 phase quadrature? I thought those were completely gone, but you're saying Philly still has quite a few still running. That's interesting.
@@VTdarkangel Yeah quite a few of those services down there. about 15 years ago I worked on a 600KW three phase generator that connected to a Scott T and then to an almost new 2 phase transfer switch that must have been a special order and cost a fortune. That was at the Youth Study Center (kid's jail). Supposed to be a lot of two phase office and retail in center city. City Hall had it at one time, but as far as I know it's all three phase now. Lots of the old equipment in the basement abandoned. There is even some abandoned DC equipment down there probably installed in the 1800's.
Bridesburg, fishtown and port richmond has a lot of 5 wire ariel drops yet. It's slowly been getting changed though because two phase equipment is impossible to find, and most of the rewind shops have closed
@joecummings1260 The only 2 phase load in my area that I know of was shutdown about 10 years ago. Actually, it burned down, but they elected not rebuild it. I figured there were more out there, but I figured they were few and far between.
Delta high leg is still quite common in my neck of the woods. Much simpler if you've got a lot of mechanical loads, want less than 250V to ground and a much smaller amount of 120V loads. Residential transformers can be used in this way, and reduces the total number of different transformers used in a power delivery system.
As a retired Dutch engineer, working with single fase and three fase only, without any half tap at 120 Vac, this video finally explains how it works in the US. Thank you very much.
@@dohabandit I agree, however a 30 mA GFCI at the the distribution panel takes away the extra risk of the 230 Vac.
And @ higher voltage = less amps for same work which = fewer KWA…. = less consumption and lower cost…. Welcome to America…😅😅
@@FourbrrlGrabber it's als insane that the US has so many distribution lines, The Netherlands has 0 distribution lines.
In dutch phase is fase?
@@wyldmon yup
This UA-cam channel is gold-mine
In 2005 when my mother remarried and moved to my stepfather's farm, we had an open delta 3 phsse, because we had a grain dryer, conveyer and large auger with 3 phase motors, with the majority of our loads being 120/240 single phase, transformers on the roadway, pole with meter and site disconnect in the middle of barnyard, single phase ran to house, 3 phase to barn, where there was a 3 phase panel dedicated for the motors, also feeding a single phase panel beside it for the other loads. Otherwise roughly 1/3 of the panel slots would be wasted because the B phase (high leg) is unsuitable for single phase loads, which is a major disadvantage of a 4 wire delta service and thus the 208Y/120 & 480Y/277 (or 600Y/347, if you happen to be in Canada or a few areas in the US) is a much more common and useful configuration.
Open delta is still fairly common on some farms and small commercial buildings where the customer has mostly single phase loads, while also requiring limited amounts of 3 phase power, since it's cheaper to set up than a wye bank.
That’s a neat explanation of practical use.
Half semester of basic electrical theory in 24min.
Where were you when I was graduating? 😂
Amazing.
This might be a bit dense for a total newbie, but I'm finding it a wonderfully efficient, clear, and comprehensive refresher that really brings together the substance of multiple other longer sub-topic videos.
Thanks for the breakdown. As an electrician for 14 years, I've always wanted to know how the different configurations of delta/wye affect voltage/current output. The most intriguing thing is the ungrounded delta primary which gives uncommon voltages to ground. Very cool....
Audio engineer here, this is super super useful to my field as well. Knowing power is super important when tapping into these commercial feeders, knowing this kind of stuff will get me paid more. Cheers!
I was an industrial electrician 35 years ago. Great video.
Very nicely done. I earned my BSEE from NorthEastern in 1991. I used pencil, paper and calculators back then to study, study, study and learn this material. This video explains the physics behind transformer and power transmission technology very simply and clearly.
Funny enough, the switch from solid block cores to plate stack cores wasn't because of eddy current losses, although it was a nice bonus. It's mainly because it's cheaper to stamp out a bunch of steel plates and stack them, rather than milling out the shape of the block.
I find this quite useful and at least interesting even as non electrician. I highly recommend watching the video 3 times and take notes. This is an entire year of schooling packed into a 24min UA-cam video afterall.
What strikes me the most, is how EVERYTHING is arranged and explained, starting with a large envelope and then going right down to the small parts and the physics that make it all work.
Very well put together!
I just want to say big Thank you for your videos. I am in an electrical apprenticeship and these videos are really helpful with understanding how these equipment and thoery works. Ever since i started watching your channel i have become better at trouble shooting and overall a better electrician! THANK YOU!!!
pay attention in class and read the books there’s vast amounts of electrical jobs and it starts there
This brings back memories of Army Corps of Engineering for 52D power generation school. Why I never pursued this in civilian life is beyond me, because it was so fascinating and practical. I was the honor grad in 1988 probably because I really loved power and electrical systems, as well as trigonometry.Synchronize your generators and create your own power grid!
I was an electrician for many years and I think this video will inform those who have no idea how electricity works. Basics are an essential element to understanding. I am also an amateur radio operator and appreciate someone instructing those who have an interest in such material.
I really needed this video 6 years ago in electrical school. I've never seen transformers visualized so well!
I'm in an apprenticeship, in the commercial and industrial end. This is fantastic, I've watched several of your other videos. They're very easy to take in, you have a gift, my friend I thank you for your contributions.
this channel is 100 times better than my professor......
And you don't have to listen to their woke BS.
@@jagboy69 Tell me you never went to college without telling me you never went to college.
@@uzlonewolf Embry Riddle back in the 1990s. Woke wasn't a thing like it is today.
@@jagboy69rollins college a year or two ago, constant woke bullshit the whole time
@@jagboy69 like what
I need to watch the rest of the video, just noting at the start the video shows peak voltage of 120v; 120 is the RMS voltage, peak is 169.7v.
Good catch! I hadn’t noticed that mistake
I went straight to the comments when i reached that to see how many others noticed
The formula to calculate rms voltage is √(integral(I*sin(x))^2/x)
@Loanshark753 or for a clean sine wave ...just peak*sqrt(2)/2
I'm guessing that wasn't a mistake so much as ... "ehh.. not really, but uh... we'll get to that later." And, TBF, at the end, the voltages were marked as RMS.
RMS was one of the hardest things for me to wrap my head around, so I don't hold it against anyone to gloss over that for the sake of illustration.
THANK YOU! This is the best layman explanation I've ever seen.
That was a GOD level explanation. Not even professor level...... But, GOD level ....... I bow down to you
He did amazing
Great video, I like how you always go much more in depth than I expect while still keeping it simple to understand with some basic knowledge. Best channel in this niche IMO
Thank you for all you do! This is amazing! I'm currently an electrician in training and this kind of concise detailed content is what society needs.
As an electrical engineering student, your content has been helpful for my entire career (including this one) and this video is no exception, thank you for all that you do!
Lineman for a power company here.....This was an EXCELLENT and VERY well laid out video!!
Thank you for this video. So detailed and easy to understand. Goes step by step and doesn't go backwards, but rather it references what you learned earlier in the video and applies to the current topic.
Thoroughly enjoyed. Even your sponsored ad was great. If I ever need a 3ph, MW transformer for my garage shop, I'll be sure to contact Maddox🙂
Thank you @JRo250! Let us know if we can help with any of your projects.
I liked the entire video honestly. I have been using it to help teach my technicians what 3 phase is and how it works. Your videos are very informative and well made. Your content is a valuable teaching aid in my industry.
Excellent. I’m an electrician that is trying to increase his knowledge at a very late in life age. Some videos put me to sleep quickly. Yours are interesting. Thanks
This is 5 year course, in 24min.
5 years? More like 2 months
I use Maddox Step-Up/Boosting and Step Down/Bucking Transformers at work in both low and high KVA applications. I recently used a 208v Wye Secondary as a primary and stepped up to 480v Δ as secondary. I called the transformer company first to make sure this was allowable. It was and I have no issues. Maddox is a very knowledgeable company to work with and have great people on staff to answer any questions about their products and have many transformers in stock.
I use your videos to help train my technicians. They are very insightful, and well presented. Your channel is a valuable tool.
Videos can be helpful for apprentices, but as a 35 year electrical contractor I wouldn’t use it to train them. Classroom works best.
In my State it takes 10,000 practical hours and minimum 4 years of night school to get your General journeyman card.
Back in the 1990s when I was getting my journeyman card we didn’t have UA-cam but we did have well researched videos from the IBEW.
Excellent tutorial. The one item worth expanding on is the phase shift from a wye-delta (or delta-wye) transformer and how that could be exploited to get an even more constant power output (a follow-on from @3:20 in your video). If you use both a wye-wye (no phase shift) and a wye-delta (phase shifted) transformer pair the output power would be more constant. With rectifiers on the output, this combination is sometimes used to provide a close approximation of smooth DC power for some subway systems. This is also used with an additional inverter on the output to run induction furnaces.
Now, I don’t buy things from people on you tube, but your mugs are awesome 👏 putting a diagram on yours is brilliant..🙌
Thank you, glad you like it
The best explanation I have seen. Thank you!
As a new Substation Engineer with a degree in Computer Engineering, this video is perfect since I am studying for my FE and I come from a background where Power is not covered. I will recommend this video to my new grads at work! Awesome work!
Funny how different it is in various countries. In Poland, for instance, majority of households (at least not flats, but freestanding buildings) uses 3-phases split from 400V.
Every apartment in Sweden has 400V 3-phase without exception. The big advantage is that you can use much smaller cable area and other equipment such as switches can also be made smaller and cheaper due to lower currents.
Same in Russia 3-phase 230/400
And in new build areas in Norway after about 1995. Before that, 3*230V IT network with no neutral.
@@DnvGoodwin555sometimes it's still 220/380 in old networks. At least 10 years ago I've seen some of them.
@@smolboyt >>sometimes it's still 220/380 in old networks.
Yes. According GOST 29322-2014 voltage should be 230/400 +/- 10% . So old voltage 220/380 in old networks is still "normal" according GOST. Meanwhile new networks works with 230/400.
Here in northern Europe, it's normal to have 3 220v/400v phases in apartments and houses.
Oh this video definitely only applies to the US grid. Hence why he even showed 240 Volt split phase, which is pretty much only used in the US and Canada.
@@jaafersa I knew this would be about the NA power grid the moment he mentioned 60Hz, because here in Europe our AC is @50Hz.
Yeah, it annoys me when American channels have British narrators because it takes me longer to figure out they are talking about the US, interesting video all the same but their power set up is nothing like Europe's.
Excellent work. Most of these videos stop at kindergarten level. I remember being thoroughly confused the first time I encountered a high leg delta. Superficial knowledge of the theory without fundamentals is good for trivia night and useless in a dark sub-basement with a multimeter that's telling you that you don't know what you're doing. Thanks for going through the trig; the math is really straightforward once you actually start paying attention and working it out properly.
The different aspects of xfmrs covered is amazing, as well as, the clear narration. However, I would have to say the part of the video that really drives it home is the visuals and animation. They make it so easy to follow and understand.
Top explanations, thank-you.
I was not familiar with "high leg delta", I have never come across it here in the UK. I was however aware of the 60hz USA vs 50Hz Europe. The centre tapped 120V domestic mains is a US thing too. In the UK we just get neutral and a 240V line.
This video is incredibly creative and informative! The way it explains the three-phase concept is both clear and engaging. The most enjoyable part was that I finally understand how three-phase works, thanks to the excellent visualizations. Great job!
Great video! Glad to see youre gaining enough momentum to pick up some commercial interest.
Thank you. It's super relevant too so double bonus.
Fantastic video, but to explain the ground in the y configuration you could also explain the cases of simmetric and balanced where current and voltage have the same module and phase shift of 120 degrees therefore in the central node the sum of the 3 currents is 0 so as to obtain the return of the neutral
This is hands down the very best channel on UA-cam BY FAR. you have taught me and the rest of us so much. So very very grateful for the engineering mindset. You've turned me into a total nerd and I LOVE IT!!
For most places/purposes 120/240 distribution beats 120/208 distribution. The extra 12 folks will keep motors happier. Three phase is a PITA to actually use directly on motors. It often requires protection again phase reversal.
If a smaller customers decides he wants 3 phase motors, today the best solution is that put in a VFD (Variable Frequency Drive) and provide motors with the most efficient voltage ans power.
Hands down the best video on power delivery. I think I’ve seen over a hundred. Fantastic work.
I do not go into splitfase as we have 230/400, all our grid is 3 fase from producer to home. Most of our grid except a small part of 10kv and 60kv (60-150-400kv are airborn usually) is plowed down in the ground, and it will create less blackouts in adverse weather. All these different voltages and conversions, 120-208-240-277-480, 230/400 50hz is all we need in 90% of cases.
An excellent tutorial. Reminded me of the one "power" class I had in Electrical Engineering where we had to learn all this stuff and do Delta-Wye transforms, which I have never used since....:) Not much demand for power engineering in microprocessor development. But, we had a great time in the lab hooking up 3 phase motors to another 3 phase motor run as a generator. Didn't want to connect the phases wrong or the "generator" would just around on the test bench.
What I really appreciate is the explanation of the various configurations and transforms to get from 3 phase to single phase residential. It's often hard to explain to people why industrial drops are so different than residential drops. I am forever grateful that we standardized on 120V in the US because I had to work on 240V systems in Europe and it always seemed lots more dangerous.
Where I'm from reversing any two wires on a three phase motor just makes it run backwards. Of course you want to be careful if whatever the motor is turning doesn't like spinning backwards, otherwise it doesn't matter. What is "justing" around on a bench mean?
Also, where I'm from, you can run a three phase motor on single phase, plus some extra stuff to get it started spinning, then generate almost real three phase power from it. So, if you've got industrial manufacturing equipment in your garage at home, you can still run it at reduced capacity...
Just started working in electrical distribution I definitely needed this. This is great!
This is amazing stuff. I have a BSEE with a focus in power systems and this basically condensed a years worth of upper division EE courses into a beautifully illustrated and easy to understand video. I wish I had resources like this when I was in school. Fantastic work!
I really like your videos! There isn't another UA-cam channel that does explain electrical engineering as you do! CHEERS. Also, do you mind making videos about smart grids, dynamics and stability, or HVDC topics? I am currently doing an MSc in Power Engineering in ICL and I find those topics quite interesting to promote Electrical Engineering to fellow students.
Glad to hear you enjoy the content and hard work. I'll add the topics to the list of ideas, best of luck with your MSC.
Thyristor time
The US electrical system is so complicated. We do have local transformers for each collection of houses. I live in the countryside in Sweden. We have 3 houses with property lines next to each other with a fourth a few hundred meters furter down our road. We have a transformer split between us and all houses, get their own 400V 3-phase cable to our meter box, and from there goes 3-phase into the house where it's split into three single phase 230V. No extra split phase like you have, and only two voltages to keep track of. Commercial buildings can get their own high voltage connection, which is anything above 1000V, but that is only if your industry need more then 0.5 MW of power or they recommend that you keep to the normal 3-phase 400V since it's most likley to expensive to get if you not have need of it.
The nearest town also only has one transformer for the whole town, but that is a bit bigger than the one we have. That one even has three fly wheels to stabilise the load, which bigger transformers have sometimes. Almost all the grid here is underground as well. They dug down the cables a couple of years back since it needed to be replaced anyway because of the age of the air cables and we had much problem with power outages during storms and such and almost none since then.
Thats how it works in America on the residential side in the suburbs. Usually you have 5-6 houses on 1 split phase transformer that is fed from a local substation, might be a 3 phase if the grid you are connected too is old enough especially right outside of NYC. The only time you usually get 1 transformer to a house is in the rural areas where the houses are more spaced out.
This explained so much to me that I probably should have already known. Thanks!
I'm a mechanic learning a bit of electrical over the years. Was good up to about the 9 min mark.
Will have to come back and rewatch when my attention span and cognizance returns 😂
Excellent explanation and video so far and thank you!
Wow! Spectacularly concise info I've not seen elsewhere in one video, or 10.
In Europe we have 230/400V and easier installation. There are also some different voltages like 690V or 500, but mostly is 230/400V. And I's used for all applications - home, industry.
and it was partially due to lack of material for wires after WW2, as higher voltage required small gauges and less copper. In the US there was no shortage of materials
Thank you Big bro! I'm graduating this Year as an Electrical Engineer, your videos have helped me a lot...Love from India ❤
This video is why in Europe we mainly just have one type of transformer. Everyone except heavy industry etc use 220 -240 VAC so none of the delta or wye nonsense. Just imagine, not just the less maths but the fewer spare parts to carry to fix the damages. Also, because of standardization hopefully cheaper products. Higher voltage finally means a greater margin to serve. As for safety, even 12vdc can kill you under the right conditions. Notice the term "right conditions" and avoid it at any cost.
12V would take very VERY extreme conditions to kill someone. V=IR. It takes about 0.1A to kill someone. With 12V the human body would need a resistance of 120 ohms to be at that lethal mark, or the current would need to be sustained for a long time. For reference, a soaking wet person is around 1kΩ... Would take closer to like 40V to get dangerous.
Really we are talking about energy here though. It isn't volts, it isn't amps, it's the combination of the two over a period of time. Factor in volts, amps, timeframe, and path of travel before saying anything is lethal or nonlethal
Most modern domestic networks in Europe is 3 phase 230/400V TN networks.
This is such a good explainer video - I wish this type of material was available back during my college days.
Electrical engineering teachers need to be showing this vid in their classes (and the school then donating to the creator).
Great video! I got a clear understanding of Delt and Wye configurations and how to perform basic calculations. I downloaded the 3Ph Transformer Basic Cals pdf, and helping it to stick even more.
Very happy to see your phase explanation as many electricians refer to the two 120 VAC lines in your house as phases. This is incorrect as you properly explain.
Man your videos are nothing short of amazing! Thank you! This si very much appreciated. Please continue making these amazing videos! 🎉❤
Just had my supply upgraded here in the UK, was a 4 property looped supply now 3 phase, nice bit of future proofing.
That's a ton of densely packed info without any fluff, good stuff
After so many videos, becoming more
and more concise. Well done Paul.
Finally a video i cannot watch in 2x. And need to rewatch at least once.
Can someone explain why the resistance scales with amperage but not so much with voltage? Why do some countries build higher highvoltage cables than others? I forget the formulas
Excellent education and nice slow ramp up in complexity, I'm counting this towards pdh. I bought a mug, great job!
Hope you enjoy it! Thanks for the support
Nicely done, very concise and comprehensive. Thank you for your time and expertise offered for our benefit in this production.
good video explains the US system nicely. The only thing that was disorientating in the beginning was a british person narrating about a 120v 60 hz US system. in most countries that use 230/240v 50hz (talking for domestic not heavy industry) the feeder is 11KV 3 wire 3 phase that goes into large delta to wYe PMT ( located in a neighbourhood) stepped down to the 415v 4 wire 3 Phase (l1,l2,l3 N) from where you get 3 legs of 240v single phase L N. Large homes and building get the 3 phase 415v connection, small homes, apartments get just one phase. with 3 phase supply the neutral return wire can be the same size as one hot line as currents cancels each other out because of the phase difference etc.
are you talking about british electricity? most european houses (& even some apartments) get 400v 3 phase
0:22 In Europe the output is always a Y configuration.
The voltage is 220 to 240 volts to ground. Or from phase to phase 380 to 420v.
Often referred to as 230/400V...... 230* SQR(3)=400 V
Rarely there is 230V from phase to phase (and 127V from phase to ground).
The domestic sockets are connected to 220 to 240V 50Hz. Mostly 230V 50Hz
Typical voltages in Germany: High voltage: 380kV, 220kV, 110kV. Medium voltage 20kV, 10kV. All 3 wires.
Voltage for consumption: 400V 230V AC 3 wires + neutral wire. Sometimes extra wire for street lighting.
Electricity for train: 15kV overhead line or 110kV 2 wire for transport.
It's just amazing.. honestly. Every engineer that came up with this. Even Nicole a Tesla.
At 11:03 it took me a while to reason why the sqrt(3) is in the denominator for secondary outgoing power from each coil, rather than the top. Then I remembered that 3/sqrt(3) is sqrt(3). There are three coils and you're calculating power per coil, so the 3/sqrt(3) is simplified to sqrt(3).
Top tier explanation as usual, can't thank you enough for all that you do!
This is very good explanation for non electrical people, good job
the way you teach is so effective! thank you for taking the time to make this!
Excellence (especially in knowledge sharing) is incredibly enjoyable as well as valuable. Many Thanks!
Great video! I studied this stuff years ago out of text books but your video is a lot more interesting making it easier to comprehend.
In Denmark we have 230v single phase but also 400v 3 phase in residential.
So what makes design engineers choose one transformer configuration over another? Type of equipment and demand on client side is all i can think of? Why would you want a delta vs a Y on secondary? If voltages are the same? Are there benefits/drawbacks to have Y as secondary for neutral safety?
The Delta and Wye transformers are not the same output voltage. I worked at a place that had 480 volt service to the building, and they had a 208 volt wye transformer on the roof to feed several Mitsubishi three phase 208/230 volt heat pumps on the roof. They had dual input voltage ability, and they could take in 208 volts at 125 amps or 230 volts at 100 amps MCA. (actually 124 MCA at 208 volts and 93.5 MCA at 230 volts.). So if they had known what a Delta transformer is, they could have picked a smaller delta transformer, and fed the units with 100 amp breakers and 100 amp disconnects, #2 wire instead of #1 wire, and saved money. The cost difference between a 100 amp three phase outdoor disconnect and a 200 amp is a lot of money!
They did not need to run any of the 120 volt circuits from this transformer, and do not need to put in a neutral wire, only a ground in a Delta system. Overall cost savings is smaller wire size, the 100 amp disconnect instead of 200 amp, and circuit breaker cost. The higher voltage (240 volts VS 208 volts) means that each motor will have less amperage going through it, so less heat loss, and less voltage loss due to lower amperage.
With the normal 208 volt wye transformer, the main advantage is you can also get 120 volt circuits from it easy. So had this transformer needed to run 120 volt circuits, then a wye transformer would be more a requirement. But this was only running the rooftop HVAC systems, not the 120 volt systems inside the building, that had other transformers.
Hello. I liked the part from 16:06 when you explained trigonometry applied to the wye and delta transformers. Thank you.
Wow, you made this very fun, My later Father was a master Electrician, and I have a HAR/V . It a very technical field, and takes a lot of mental work to understand it. Sad that most young people here in America, do not like math and science, because our great nation is built on this area of science and physic .
Any chance you could follow this up with pros and cons of each system and give examples of why they are selected?
And has the selection been changing because of the reduced need for 277V lighting (moving to 120V LED)?
And include thoughts for other upcoming changes (maybe to accommodate energy storage systems}?
Thanks, as always, for the excellent content!
Hi, If the building was built with a 277 volt lighting system, then changes from fluorescent to LED lights, they are not going to switch the wiring to 120 volts, it is just to expensive. Also the 277 volt lights can put 3,500 watts on each 20 amp circuit breaker, so a lot less wiring is needed for a large building. The maximum possible load on a 20 amp 277 volt circuit is 16 amps or about 4,400 watts. A 120 volt circuit at 16 amps is a maximum possible 1,900 watts. Most are limited to only about 1,800 watts.
What the electricians did at one place I worked at, they had a conversion LED lamp, 4 foot long, and if they already had a electronic fluorescent lamp ballast, they would install the LED lamps, and they worked just fine on much less amperage. However the older magnetic ballast would have to be replaced to use the LED lamps. Most of our buildings used 120/208 lighting systems, not the 277 volts, only 3 buildings had 277 volt lights.
Beautiful video, now I would ask something.... If I bring an european appliance designed for 240 V ( line and neutral) and connect it in US to 240 V- 2 phases will it work fine ?
if it's the 240v single phase split phase then it can work but there's the 60hz problem:
if the device says 50/60hz then it'll work just fine
if the 50hz device has a motor then it may not work properly or even break
if the 50hz device is an ac/dc adapter like an rvl-002(eur), rvl-002(ukv) or rvl-002(aus) then it'll likely still work with 60hz
My brother brought back some 240 volt appliances from Germany, including a vacuum cleaner. They all worked fine on 240 volts in America. They had a refrigerator, and some other appliances. They did not bring the stove. In Germany, when you rent a apartment, it does not include the kitchen cabinets and appliances. If you want to buy them from the tenant that is leaving, you can do that, or they might take them with them to the next place. My brother was offered a small amount for his cabinets, so he had them put on a cargo container headed to America, paid for by his boss when transferred to America. It actually cost him a lot of money go get a couple of additional German cabinets when installing them in his new American home, with a larger kitchen.
Excellent, excellent video! Well done sir! This is by far the best and clearest video I’ve seen on this topic. 👍
Best video I have seen explaining the intricacies. Thanks
This video has answered a question that's been bothering me for a long time: when I use a Public Level 2 EVSE to charge my car, I only get 208 volts/32 amps (6,600 watts), whereas when I use my own EVSE at home, I get 240 volts/32 amps (7,680 watts). Public chargers always take 45 minutes longer than my home EVSE to charge my car, and now I know why! Public EVSE's, typically in shopping center parking lots, are apparently being fed off of 3-phase, 480 volt Y or Delta transformers that only supply 208 volts per phase, whereas the NEMA 14-50 outlet in my garage at home is being fed from a center-tap 240/120 transformer that gives me a full 240 volts across the two hot lines.
A 3-phase transformer with 480 volts per phase, is wired to give 120 volts on the secondaries, between any 1 of the output phases and the neutral. All well and good for supplying 120 volt ac wall outlets and lighting systems. If you tap any two of the phase coils, which are 120° apart in phase angle, you will see that when 1 phase is peaking at 120 volts, the other phase has 88 volts, and the combined voltage at that moment is 208. In a residential transformer, the magnetic field of the single phase 480 volt primary feeds a secondary coil wound 2:1, yielding 240 volts across the full coil, or 120 volts across either end of the coil and the center tap.
This leaves me with just 1 question: why would commercial buildings be okay with 208 volts for running high power equipment, when standard residential service is 240 volts, for powering an electric cooking range, electric water heater, and heat pump or a/c compressor? Especially when you are powering an electric motor, like an a/c compressor motor, I would think that a motor designed for 240 volts would maybe overheat, or run at the wrong speed, if fed only 208 volts? Why isn't all power service 240 volts for everyone?
Loved the video! Amazing work as always!
Typically a step- up WYE Delta transformer is used between a generator and transmission line connected with the Generator connected to the Delta windings and the Transmission system connected to the WYE windings of the transformer . This provides isolation so a "Line to Ground "fault on the Transmission line cannot make its way back to the Generator as it see's it's "source "as the Transformer not the Generator. There will be a 30 degree electrical displacement ( or shift)between a WYE / Delta transformer primary /secondary winding voltages .
Another fun fact with a 3 Phase Delta transformer is if you lose power to one input phase it can still produce 3 phase voltages at a reduced capacity of 40% . From what I read years ago was that this is why they used this configuration for critical facilities such as Hospitals for more reliability .
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Totally bought one of those mugs! Thank you!