Three-Phase Power Explained

[@dane1234abc1]

I remember my EE professor from my undergraduate days filling three chalk boards with a beautiful derivation of WHY three phase power, why not 4, 5 or n phase power? Answer: Because three phases was the minimum number of phases whose average power was a constant. Additional phases require additional windings and transformers, so go with THREE phases for the most efficient power grid. Beautiful. How I wish I had a video of his derivation. Even after over forty years as a now semi-retired Electrical Engineer who dealt with RF systems (FM broadcast, TV broadcast, and microwave), it was masterful derivation.

[@theachebes5724]

Wow good testimony. Can you mentor someone? I am an electrical engineer

[@dane1234abc1]

@@theachebes5724 Not on 60 Hz AC power. My AC power/motors experience ended with college. My experience is in RF-- its propagation, and also loss/gain calculations for hight power radio and TV stations. Did several 5 MW ERP/60 to 80 kW TPO analog TV designs, but with digital the maximum allowable ERP is just 1 MW, so TPO's are typically in the 40 to 50 kW range. Still, it's 6-inch rigid coax line to handle the power. No more waveguide transmission lines, given that UHF TV now stops at Channel 36 (605 MHz) instead of Channel 69 (803 MHz).

[@mcrbyn]

i'm ee undergrad student, can i get your contact?

[@mhlwebs]

most stupid explanation

[@ALM1936]

120V/240V "residential" power comes from a single 240V phase supply line produced from a step-down transformer (secondary side). The primary side of the transformer is fed by one phase (1 of the 3 phases) from the substation (commonly 12kV). The secondary side of the transformer is stepped down to a 240V SINGLE phase output. Because the secondary of the transformer is split into two halves with the neutral (or ground) at the middle of the transformer's secondary winding, two 120V reference-to-ground signals are produced. So there are 3 wires coming from the secondary of that transformer, (2 hot--1 wire on each end of the winding, 1 neutral/ground wire tap at the middle of the winding). Measuring the voltage potential from each hot wire to the neutral wire yields 120V. Measuring the potential difference from one end of the winding to the other end yields 240V (ie. 120V + 120V...actually, 120V minus a negative 120V). This configuration is also called a split-phase system. I added this comment because at 8:00 of this video, it's not clear enough, because it says "it's 2 single phase lines". Technically, it's one phase split into two halves and the waveforms are "out of phase" only because they are referenced to ground at the middle of the transformer winding.

[@fuckjewtube69]

I understand all that 100%. What I can't understand is how is there not live power on the neutral?

[@ALM1936]

@@fuckjewtube69 here’s my understanding, take it for educational purposes, not instructional or safety purposes: the neutral wire DOES carry current, specifically the returning current through the home’s loads (ie. lightbulbs, tv’s, appliances, etc…). The neutral wires coming from the loads in a home’s breaker panel are tied to ground and the neutral wire coming from the secondary transformer is also tied to ground at the pole. Because neutrals are tied to ground, the Voltage potential from the neutral wire to ground is minimal. Power can be calculated by multiplying Voltage by the current (Amps). If there is practically 0 volts on a wire, then the power is going to be ~0 as well. **That is why it is possible for a person standing on the ground to touch a home’s bare neutral wire without getting shocked. It is also why the neutral wire coming from the pole transformer into a home is a bare conductor (no insulation). **If there are situations like lost/disconnected neutrals or grounds; ground faults where limbs of a tree touch bare high voltage wires; etc… then this statement may not always be true, it may be possible to get shocked. In summary, it’s about completing a path for current to flow, but also how much force (aka Voltage) behind the current flow; and it depends on exactly what two points in the electrical loop/circuit are being touched/connected in order to cause current to flow.

[@johnkenneally4662]

Best explanation of 3 phase power I have come across. Currently I am an apprentice electrician.

[@jamesspash5561]

Great explanation of three phase. My son is entering the generation field and this will surely help him better understand three phase vs single phase. Me, 30+ years in hydro generation, so sometimes Dads explanations might be a little over whelming. Thanks.

[@jakefeisel7348]

I've was only wondering about 3 phase for about 25 years now, thank you.

[@enyakang6950]

Is there a Grammer error? I have was??? Think you for your advice

[@bobsmith3291]

Say that again in English

[@ianstobie]

@@enyakang6950 Yes. He meant "I was only wondering about 3 phase for about 25 years ..." but another way of saying it would be "I've only been wondering about ...". So he probably started one way then switched to the other without noticing. As you probably noticed, the "only" is ironic, because 25 years is really a very long time to wonder about something. Only been wondering for 25 years! I've been wondering for longer, as I'm probably older and it's a long time since I first heard the term.

[@niallm-i6s]

This is one of the best descriptions and explanations on the Internet. Thank you

[@janyjozsef]

The conductors between a voltage source and a load are called lines, and the voltage between any two lines is called line voltage. The voltage measured between any line and neutral is called phase voltage. For example, for a 208/120 volt service, the line voltage is 208 Volts, and the phase voltage is 120 Volts.(9:32) EU: 230VAC => Phase voltage 400VAC => Line voltage.

[@alexcoble8819]

What about 3 lines carrying 120 Volts each? Is there more than 208 Volts being supplied in that circuit?

[@GH-oi2jf]

Voltage is a potential difference between two points. It doesn't make sense to say that a line carries 120 volts. You need to state the configuration precisely.

[@jamestaylor3596]

You are a true educator, not only do you make it understandable, you also create the desire to learn more, many thanks

[@sisir22]

सर आपका वीडियो बहुत बढ़िया और शिक्षाप्रद है. 3 फेज एसी को आपने अच्छी तरह से समझाया है.

[@goedelite]

This begins with faulty description of the effect of the north pole of a magnet rotating by a fixed linear conductor. Electrons do not flow towards the north pole of the magnet. According to Lenz's Law, the electrons in the conductor flow in such a direction as to oppose the motion of the passing north pole. That means that as the north pole approaches the end of the linear conductor, the electrons flow in such a way as to create a north pole at its end. As the north pole passes and receded from the conductor, the electron reverse their flow so as to produce a south pole at its end, to attract the receding pole. Lenz's Law is really a consequence of Faraday's Law of Induction, which states in mathematical terms that the direction the induced magnetic field is always opposite to the direction in which the magnetic field is increasing. The electrons in the conduction flow in the direction required to produce that opposing field. In the mathematical expression, the negative sign is what Lenz's Law expresses in words.

[@paulfrischknecht3999]

Absolutely, good point. I saw the same wrong explanation in other videos about AC...

[@GunterPSparks]

Boring!

[@alexlatte2754]

This is the best explanation of phases current I came across 🙌🏾. The clock analogy made it so easy to stick it in. Thank you, you are a blessing 🙌🏾 ❤

[@stevefal]

I don't understand the 10.8kVA calculation. I get how each pair gives 208V x 30A. But why do you multiply by 1.732 again to get the total power for three pairs? Why not multiply by three?

[@raypitts4880]

there are such things as magnetic influance

[@beltrams]

If you look at each individual leg, you have 120V X 30 A = 3600W, then you can multiply by 3 and get 10800 W total, but taking each 2 leg pair and multiplying by 3 doesn't work because each of the 3 legs, A, B, and C is shared in 2 pairs (A to B, B to C, and C to A) and thus, each leg cannot devote its total power to each of the 2 pairs it is simultaneously powering. There has to be a derating for sharing the lines and when the calculus of the RMS sinusoid wave form is done that all these overlapping sinusoid wave forms come from (it's been years and calculus escapes me now), there are definite integrals that solve down to the square root of 3 as the deciding factor to multiply by.

[@okaro6595]

You can multiply by 3 but then you have to use the phase voltage 120 V. The power you get is same whether you connect to star or delta. It is just simpler to understand the star connection as you can essentially for get the phase angles and view it as three 120 V circuits so 3x the power.

[@paulfrischknecht3999]

Errata: At 0:40, the sine waves are 60 degrees apart, but they should be 120. Magnets do not attract or repulse electrons. Varying magnetic fields cause electrons to experience a perpendicular force, which is why you need coils in a generator and motor, straight wires would not work properly...

[@sdj198801]

Been studying for an upcoming test and needed some refresher material. You explain the material beautifully. Definitely have a knack for explaining complex processes in a simplified manner.

[@garysinghsidhu6390]

this is the best explanation I have watched so far

[@imbezol]

I don't get your graphs at 0:40 and 4:50. Why are the phases not spaced out evenly at 120 degree offsets?

[@coloradowilderness3139]

Simple , Easy , Concise , Thoughtful . Thanks

[@ZZZZ-zg3zb]

as an EE I want this video to be tough in colleges, it explains it perfectly , I want to go back to college, who would not want to be in college -all you have to do i study nothing else lol kids these days have it made with the internet, this is a great video, I watched it twice because its so well done, who ever did the animation I want them to do my power point stuff and make it like this

[@brightwriter]

Another, unmentioned, benefit of 3-phase power is that 3-phase AC induction motors are much simpler, not needing a shaded-pole device on the field windings or a special startup motor to get the principal motor started. A 2-phase AC induction motor, like an internal-combustion engine, can keep itself going but needs a separate device to get it started.

[@rcadventure44]

We don't use 2 phase. We use single phase, with 2 lines 180° apart.

[@Bramon83]

Common misnomer.

[@davidjames1684]

True (sorta). It is actually 2 phases, but they are phase locked 180 degrees apart and we have access to the 2 hots and that center tap. So in reality, it is a combination of both single and double phase. Imagine if someone had 2 lines each 120V and each having a neutral center tapped to the same transformer's secondary winding. Next imagine if they could put say a 45 degree delay in one of those lines. Would it then still be single phase or 2 phase? If 2 phase, then you are saying that when 2 lines are 180 degrees apart it is single phase but is it really? Some people would agree and some would disagree.

[@hellwithit]

Brightwriter also you can reverse direction on it

[@junkdeal]

If the starter winding is out or the centrifugal switch is non-functional, you can hand-spin a single-phase motor and it will run both ways. We had a bench grinder with a failed "cent" switch that would have sent power to the start winding. I put a momentary-contact switch in the start circuit, and then at the moment I would turn on the grinder I would push the added switch until it got up to speed, and then let that switch go and all was well! It we didn't hit that switch the motor would howl and not turn. If I hand-spun the grinder wheel backward and then did the other steps before it stopped drifting backward it would run in the wrong direction! Also, if I am not mistaken, the 3-pase motor was invented first, and it was supposedly a battle to make an effective single-phase motor after that.

[@johng.6129]

thanks for this. I'm a recruiter and working with construction and 3 phase power is a huge plus for what I'm hiring for. Your videos do a great job explaining this to a layperson w/o the background.

[@mikenewtonninja9379]

you don't want a lay person without the background working on 3 phase, lol, lmfao, pmsl and ha ha. not unless you have a good Hoover to clean up the little pile of dust that will be left where he once stood 💥😵🌬💨👋

[@Sarcastix7]

Super video. The detailed graphics and annotations are really helpful

[@kevinbutler6475]

This is one of the best explanations/animations I've seen.

[@abdinassirmohammed1230]

Kevin Butler Woow. This is absolutely superb explanation. But why have you switched off the save button

[@raritaninc]

How do I turn the save button on?

[@jsmcguireIII]

so is the combined output modulating or are the phases so closely synchronized it remains steady?

[@deepin2urheart]

Sir any video on phase sequence and detailed discussion on Star and delta connection in Power Transformer

[@wiserdaley6624]

Thanks for the professional breaking down of information to simple yet informative points. It's great to have instructors like you.

[@pkstock372]

If we count the postiive portion of the sine curve , only can see the 2 phase add together , Right ?

[@joshuafrank9084]

you talked about other videos to watch but they don't seem to be available on the website or youtube , how do you get access to these ?

[@jasvirchahal2170]

Of all the videos I have watched regarding 3 phase power this is the best one. Thank you.

[@namae190]

Can someone explain the residential 208v, 3-wire setup? It has two 120v legs (that are spaced 120 degrees) plus neutral. Where is the third phase? And wouldn't running a powerful appliance that has a spinning wheel (maybe a power saw) with only two of the three phases cause wobbly performance?

[@okaro6595]

The normal residential system is not three phase. The legs are 180 degrees separated so the voltage between them id 240 V.

[@jorgecervantes4094]

Can it be posible to have 3 phase panel with 220 v in heach line? Can someone help.

[@Inflec]

+Jorge Cervantes - Yes, certainly it's possible but it's not a common scheme, at least in America. 220-240 volts 3 phase *is* common in Europe and most other parts of the world. The closest scheme in America to your question is the 277/480 volt 3 phase system used in factories and large installations.

[@badgardener]

Thank you. This is the first explanation that has made it clear to me

[@jamiemarshall8284]

"Positive and negative phase don't cancel" Meaning the AC frequency is non destructive? I'm not 100% sure what you meant, could you clarify? Plus and minus should offset eachother.

[@marty2872]

I've always been curious where 208v came from and this helped. Where does the sqrt(3) come from?

[@DanburyDK]

Is there a video showing what happens when one of three phases goes away?

[@javiervidoza]

During minute 6:20, there is an error. The poristion of the magnet (North Pole) is wrong for the second phase

[@jb-ik8sj]

So thats why a neutral is not necessary? The leg that is perpendicular would make the system balanced. Is this correct? If yes ten the ground only serves as a safty

[@NickDe39]

Practically all automotive alternators are three phase, when rectified, the ripple voltage was less that 8%, single phase is 100%, no need for huge capacitors. Ideal in plants when AC had to be converted to DC. Three phase motors were very efficient. Three phases 120 degrees apart inherently generated a rotating field, without capacitors so motors could be made much smaller. Wish we had three phase in our homes especially for air and refrigeration compressors and fans.

[@brlinf06398]

for people who might don't understand this comment but will understand after this reply: 1 phase ac motors are actually 2 phase, since 1 phase would be impossible to synchronize. in order to get 2 phase from 1 phase, you would need a capacitor 2 phase electricity has a sine wave with 90 degrees offset from the first

[@panzerstrelok]

i wonder how it works in a 3phase submerged arc furnace in delta connection. i almost understand it but only one thing bugs me.

[@shaggydogg3786]

At trade school 40 years ago we studied the GM delcotron alternator.. the study materials called it the six sweeps of the alternator... which btw are all three phase... great video!

[@pkstock372]

only South pole magnet can drive electrons current out ?

[@Peteralleyman]

You suggest that electrons are attracted / distracted by a magnetic field. That's wrong. It's the changing magnetic field that causes an electric voltage in the coils.

[@yaz2928]

Lenz law, basic electromagnetism.

[@mikeymcmikeface5599]

The waveforms at 4:50 and 5:25 look totally different. Why is the first one asymmetrical, as if the waves are grouped together? Just a crappy animation?

[@-danR]

9 out of 10 comments are praising this video's claptrap. Unbelievable.

[@joshbachman7706]

I was thinking the same thing. Anyways, most modern three phase industrial motors are induction and controlled by some kind of VFD.

[@dogwalker666]

@@joshbachman7706 indeed Industrial inverter drives are brilliant for matching speed matching ramps or current limit I have fitted thousands from 0.05kW up to 3000kW fun days.

[@allstarshotta]

Good vid. Memories refreshed

[@josephb6772]

Very good very clear explanation, l have been looking at this stuff for years and for some reason for me it just takes one mind and l know......yippee....what a life ...does it ever puzzle you why we have to search for so long before we find the right answer ....why can't we get it straight away

[@mikeymcmikeface5599]

4:18 Why did the electrons stop in lines 1 and 2 even with the magnet rotating?

[@coolkid9770]

@@mikeymcmikeface5599 i dont think it does becuz only one line will ever be perpendicular to the magnet every time it rotates while the other two will be parrallel to the magnet

[@TheKdizzle1971]

So the magnet moves electrons but electrons are not created?

[@LSF315]

Nice quality video. Let’s see what else you’ve got.

[@donpixote3321]

good video the way the narrator tries to go slowly through the material to make sure it gels and gets absorbed. Sadly at this point in time there are 333 dislikes meaning there are 333 confused people out there still scratching their heads with a bewildered look on their faces.

[@MichaelWeaser]

How do you get 180 degree out of phase, single phase 240v out of the 3 120 degrees out of phase lines than? is the power company before it gets to your house converting it to 180 degrees out of phase? Is the transformer or some device doing this in residential areas? I am guessing residential homes are only getting 1 of the 120 degree phase voltage lines .

[@Nunya_Business_]

Because the power company gives you a split 240V phase from a step down transformer. That transformer is almost never fed by 3 phase in a residential setting. Your power feed lines are likely 1 Hot wire, eg. 7200V and a Neutral, so your transformer is tapping off of a single phase. You would have to look at your overhead lines from pole to pole and see how many you have unless it is underground, you could even have 2 neutral(Ground) wires on the pole and/or 2 of the 3 phases but your transformer is usually only fed by one. It depends on how the utility designed your distribution system. Hope this helps you understand. A local water plant where I live is delivered 12KV 3 phase via distribution lines from a switchyard several miles away and right through a residential area, but none of the homes there are fed by those lines although they are fed by the same switchyard. The plant was there first, btw.

[@dgn107]

Residential is just one wire or one phase. That one wire goes into a transformer that steps the volts down to 120. The side that steps the volts down has just one wire but with both ends hanging out of the transformer. Those two ends connect to the two hots coming into your house. If the magnet is in north position then it's pulling the electrons through that one single wire. On one end it's like the electrons are being pushed and on the other end it's like the electrons are being pulled. Sort of like a logger sawing a tree with a two man manual saw. He can push and pull it himself (120v) or he can have a buddy on the other side helping push and pull (240v). You can connect to either side of that one wire and get 120V. When one side is +120 the other side is -120. When you connect the two together it's 240.

[@alielmesawi9200]

You have made it so easy to understand. You're such great teacher 👍👍👍👍

[@stargazer2504]

Do you think there will ever be 6 phase power? Would it be helpful or detrimental? What about other phase- 4 or 5 phase?

[@NUCLEARARMAMENT]

Efficiency gains can be had with 6-phase or even 12-phase power. However, 12-phase is the max you would ever want to go, because simply you have diminishing returns beyond that point.

[@danielfranchette5547]

the real reasons for three-phase are: firstly that it is impossible to manufacture a high power single-phase alternator (see Leblanc's theorem and the theory of rotating magnetic fields, so-called reverse magnetic fields in a single-phase alternator are disastrous), an alternator of more than a few kva is necessarily polyphase. secondly it is possible to transport more power on a balanced three-phase line (same current in all three phases) with the same amount of copper as with a single-phase line, this is a basic demonstration in electrical engineering training. for three-phase motors, three phases are sufficient to generate a rotating magnetic field of constant amplitude and constant speed of rotation (proportional to frequency, Ferraris theorem). The mechanical torque of these motors is not affected by the sinusoidal shape of the power supply. 6- or 12-phase networks have sometimes been used to fabricate rectified direct current with low ripple residue.

[@tonydyer5073]

Best explanation of 3 phase.

[@yelnats61]

Cut the music

[@robertkat]

Please explain 12 phase used in electroplating.

[@00crashtest]

This video is riddled with mistakes, especially at 0:38. Those lines are not 120° apart, because they are not equidistant from each other relative to the previous cycle's peak. Furthermore, at 6:43, it made the fundamental mistake of flowing frow positive to negative, which should be used to describe current, which is opposite to electron flow. I expected better from a large multinational corporation know as LeGrand. I guess I'll never buy LeGrand products.

[@Dz-pn7bk]

thank you so much i loved everything yet i still have a question, how does the delta 3 phases works? and what is the diffrence between these two ?

[@Dragon-Slay3r]

Two is clean

[@louiskatzclay]

At 4:48 the wave forms are not 120˚ apart. I thought that you did not understand. Later on you make it clear that you do. I knew that 3 phase had something to do with generator layout. You made that clear.

[@electricalcontractor6944]

Data centers, and other commercial and industrial buildings don't necessarily use 3 phase power because of less amperes; it is because 3 phase power provides a "more balanced system". Such buildings demand more power than dwellings even though dwellings are served with lower voltage power.

[@Corné-o6h]

If one combines 2 lines, how can it be called 3 fase?

[@darkspeed62]

Ths explanation for 3-phase power has to be easier than a 10 minute video. I still have absolutely no idea how this works.

[@geraldsobel3470]

Why add distracting sound?

[@timelesstrance3720]

So the odd number is essential for continuous current?

[@MZMA85]

I hope that you can make a video using three phase graph to educate rookie electricians about the danger of letting the phase wires to touch each other in electrical wiring, as three phase wiring nowadays is more popular for domestic electrical wiring compared to single phase

[@sudhirv.p1556]

Shall I hook up a single phase dc voltage controller which is 150 amps to phase and neutral because the voltage in the workshop is 440 v phase to phase or we need a transformer to do that

[@bryanst.martin7134]

Sudhir V.P Let me keep you alive. Measure the voltage from one phase to neutral. If that is more than 10% of rated controller voltage, then no. Do not hook it up. But, check all three phases to neutral, it's common for one to be a bit less than the two brothers. Since you didn't specify your controller input voltage, this is just generalization. Stay safe.

[@sudhirv.p1556]

Bryan St.Martin Sorry MY Mistak the Input Voltge IS 220 V

[@jefftilghman9059]

That's exactly what I was taught in the apprenticeship classes at Davis Electric. We didn't have animated video available to us.

[@kenmichael2888]

S

[@robbenmitchell7949]

Did you ride dinosaurs to school?

[@bemotivated2220]

very simple and very good explanation as i have ever seen.keep going..........

[@girl4632]

And wht if i connect all 3 wires than how much volt

[@ktcd1172]

Almost all of my higher voltage "Data Center" equipment (Printers, CISC based CPU and HD Racks) required 240v as standard. When we relocated and the power company could only supply 208v to our facility we had to have the manufacturer come out and make adjustments to operate on the reduced voltage. At least now I think I understand where the 208v came from, but why is 240v 3 phase standard for so much of the older, heavier equipment and household appliances such as stoves and dryers?

[@Nunya_Business_]

Because there was/is a common configuration that is 120V to ground on 2 legs with a stinger leg which is 208V to ground. They are 240 delta with a center grounded winding, quite common where I live. Your company probably could have bought a transformer.

[@Rob-yh2ns]

So where do you get 277 -480 from?

[@carultch]

You get a transformer with a secondary that is built to produce 277V from line to neutral. This means, if you had a distribution line at 13.2 kV, that you would have a 48:1 voltage ratio across the winding. By contrast, given the same distribution voltage on the primary, you would have a 110:1 voltage ratio to produce 120/208V three phase. So you simply have a different ratio of windings, than you otherwise would have, for 120/208V.

[@MdFaiyaz-os2vi]

Super analytical & graphical explanation 👍

[@jpo1056]

Nice job. Working as an EE in the power field for 40+ years its always been easy for me to understand but difficult to explain to laymen....especially on a napkin with a pen. 😊

[@CrazyGamer-xi8rf]

at 6:27, the polarity of 2nd magnet should be opposite right ?

[@danielfranchette5547]

the real reasons for three-phase are: firstly that it is impossible to manufacture a high power single-phase alternator (see Leblanc's theorem and the theory of rotating magnetic fields, so-called reverse magnetic fields in a single-phase alternator are disastrous), an alternator of more than a few kva is necessarily polyphase. secondly it is possible to transport more power on a balanced three-phase line (same current in all three phases) with the same amount of copper as with a single-phase line, this is a basic demonstration in electrical engineering training. for three-phase motors, three phases are sufficient to generate a rotating magnetic field of constant amplitude and constant speed of rotation (proportional to frequency, Ferraris theorem). The mechanical torque of these motors is not affected by the sinusoidal shape of the power supply. 6- or 12-phase networks have sometimes been used to fabricate rectified direct current with low ripple residue.

[@orsonstarbuck]

Had to watch 9 mins to find out why a data center would want 3 phase power. But hey, it's cool, I learned something along the way.

[@swingardjr]

Thanks for the video. First of yours I have seen and subscribed while watching. Very informative.

[@sayyidtawaqal1754]

Thanks brother I appreciate your help with this knowledge I'm said from Zanziber in Tanzania how can you please help me with this knowledge

[@tarikovictariko9123]

Awesome very instructive all the confusing that i had for my whole life was cleared in your 10 minutes video Thanks a lot!

[@χρηστοςΜπακολουκας]

ΑΡΣΕΝΗΚΟΛΗΘΗΛΑ ΠΡΟΣΟΧΗ ΤΗΣ ΔΙΑΣΤΑΡΟΣΗΣ

[@Bodragon]

(1:42) - Yes, but you do not make clear that if the "magnet" stops spinning. it doesn't matter if North or South is next to any line, the electrons also stop moving. Your explanation seems to suggest that electricity is flowing whenever the north or south pole is aligned with (ie not at 90 degrees) with a line, even if stationary. This is obviously not the case and makes your explanation quite confusing. > EDIT: ...same again at (2:45) >

[@grinnelharvard3642]

This really confused me, I want to install a 3 phase power supply in my house but my question is: could I run single phase 220-240v appliances. If yes, then how?

[@beltrams]

Most residential home appliances designed for 240V are actually designed for 208-240V as you will see on their rating plates. This is because sometimes residences (single family usually) are served by a single, split-phase, 120/240 transformer, while residences in larger buildings such as condos, apartments, dormitories, etc. are usually served by 2 legs of a 3 phase transformer service. (Such larger building living units have a regular, 2 leg, residential service panel fed with 2 of the 3 legs off the transformer.) Thus, a kitchen stove, electric dryer, etc. needs to work in both places since most people buying such an appliance can't be bothered with finding out if they have 208V or 240V and the horror of having stores stock every model of appliance in both 208V and 240V flavors would be substantial. The manufacturers simply build residential appliances with a larger input tolerance - as I say, marking them 208-240V. A stove or clothes dryer heating element will put out slightly more heat when fed in a 240V residence, but most people won't notice the slight performance difference. Likewise, the motors in those appliances, central AC/heat pump outdoor units, etc. are also built to take anything in the 208-240V range. Since AC motor rotation speeds are determined by the frequency of the power rather than the input voltage, said motors will rotate the same whether they are fed 208 or 240V because it's all 60Hz AC. The motors have a bit better starting torque on 240 vs. 208, but again, the design engineers keep the possibility of 208V in mind and make sure that their design in the AC unit, dryer tumbler, etc. isn't so critically overloaded, that the motor is inordinately challenged at startup. In 3 phase service places that have a true, 3 phase service entrance, circuit breaker panel, 208-240V loads are fed with a 2 pole breaker. In fact, in 3 phase panels, it's not uncommon to see 1 pole, 2 pole, and 3 pole breakers along side each other in commercial places like schools, restaurants, etc. One pole circuits are for outlets, lights, etc. 2 pole go to things like stoves and dryers, and 3 phase go to the commercial loads - often HVAC equipment. If you install 3 phase power in your home, then you probably would opt to have a true, 3 phase (3 leg) panel, and that's how you'd run your 240V loads - off a 2 pole breaker in that 3 leg/phase panel.

[@beltrams]

Also know, however, that many utilities, at least in the US, as far as I know, only offer 3 phase service as part of commercial or industrial service and as such there are often demand charges as well as much higher monthly customer charges compared to residential service and that's if 3 phases are even available outside on the road by your residence. Most likely 3 phases are available outside your residence if you are in a very urban location or on a main street. Otherwise, the charge to extend 3 phase service to your US residence, might be, umm.....huge. 🙂

[@arthurserino2254]

Ok, so you have two phases of 120v in your house the offset between which is 180 degrees, which can be referenced to each other to create 240v. How do you get that when the power lines carry 3 phases with a 120-degree offset between each?

[@FrainBart_main]

You can only get 208 V. In Europe we have 230 V single phase and 398 V between two phases.

[@arthurserino2254]

@@FrainBart_main in the U.S.

[@FrainBart_main]

@@arthurserino2254 I you have two phases of 120 V that are 180° apart, you can only have 120, 240 or 0 V. If you have three phases of 120 V that are 120° apart, you can only get 120 or 208 V.

[@arthurserino2254]

@@FrainBart_main then how do you explain the three phases of power we have in the US?

[@FrainBart_main]

@@arthurserino2254 ctlsys.com/support/electrical_service_types_and_voltages/

[@Richard-wk9le]

Is Europes power system of 220v single phase or 3 phase ?

[@karhukivi]

At 220V it is single phase. The 3-phase supply is 415V but any one phase is 220V. Higher voltages used for power transmission are 3-phase. In domestic situations, a transformer steps down a 3-phase supply and each of the three single-phases is used to power a different area, with as good a balance as can be achieved. A factory or industrial user can request a 3-phase supply as it is more efficient for large motors etc.

[@askarzadeh]

By far one of the best videos explaining three phase power.

[@scottj4462]

Unfortunately this doesn't show a very good representation or explanation of how an AC generator moves electrons around, but there are a number of other good concepts in the video that help explain the basics of AC power. Electrons need a loop of wire to move around, and if that were shown (and it has to be in a specific orientation), we'd see that electrons move both towards and away from a magnetic pole in an AC circuit. If it were as simple as saying electrons were attracted to a "+" or "-" as in a DC circuit, they wouldn't be able to move around the loop at all. A better explanation is that the magnetic forces of a north pole push electrons in one direction around a loop and a south pole pushes them in the other direction. In between poles the magnetic forces are near zero so the electrons stop. Further, electrons only move in a changing magnetic field so the magnetic poles have to always be moving or the wires themselves have to be moving. In a large generator magnets rotate (spin) horizontally inside stationary coils made of copper bars that run vertically and the electrons move up or down in the bars depending on whether a north or south pole is acting on them. They also move perpendicular to both the magnetic field and direction of rotation (see Flemings Right Hand Rule for Generators).

[@bryanst.martin7134]

Scott J Electrons do not necessarily need a wire to move about. Electrostatic charge is one example. Electron beam is another. Old CRT TVs used the steered electron beam for half a century. There are scan converters that still use them today. Then there is always radio. Electrons are not pushed anywhere. They are lured to an electron depleted field through what ever means they can. Open space requires very high potential levels, metal conductors very little. This is a small sample of what you left out of your educated reply.

[@terjeoseberg990]

Bryan St.Martin, Although everything you've said is true, it's irrelevant to the understanding of 3-phase power and the functioning of electric motors. The current in an antenna is negligible compared to the current in an electric motor, generator, or transformer where the electrical circuit is complete. I do agree with Scott J that the pictures in this video demonstrating the magnet and the current in the wire are a bit wonky. The video makes it appear that electrons are attracted to the north pole of a magnet, and repelled from the south pole. If this were true, we could obtain free energy by using magnets instead of batteries. Rather it's the moving magnetic field that induces a force on the electrons. Neither the pictures, nor the explanation in this video explain this, and in fact imply that this is not true. For someone who doesn't understand these things and who is trying to learn, this is going to cause a lot of confusion.

[@jeffwells641]

There's a reason he said at the beginning of the video that this video requires an understanding of how AC power works, and that if you don't have such an understanding you should watch the video on AC power first. You're criticising this video for something that was explicitly stated would not be in the video. It's like someone saying they are going to show you how to cook pasta, and you're complaining that they skipped over how stovetops work.

[@terjeoseberg990]

Jeffery Wells, I'm criticizing the video because what he's showing is not only confusing, it's wrong. The north pole of a magnet does NOT attract electrons. The wires have to be moving perpendicular to the magnetic flux lines in order for there to be a force on the electrons. The wire has to be oriented so that force is in a direction that causes current to travel through the wire. What is shown in this video will cause no current at all.

[@alparker7686]

Scott, I'm the creator of the video. If you watch the first video, you'll see and hear where I say that while I SHOULD show a loop of wire (per your comment) BUT in order to keep things simple, I will only show half. The issues with creating these types of 7-10 minute videos are: what do I include and what do i cut; what analogies do I use to explain the basic concepts which are rarely well explained. I decided that showing a looping wire would be harder to visualize and animate. It would also open more esoteric topics. My goal was to explain the topic to people who didn't understand 3 phase.

[@pkstock372]

The current wount cancel each other ? Positive cureent in phase 1 , Negative in phase 2 , will not cancel each other , Why ?

[@xierxu]

Can anyone recommend a microcontroller that puts out 3 pwm signals with deadtime?

[@RayThackeray]

Maybe one of you clever people can help. I have a Northern Lights 25kW generator and I planned to run a 3-phase 240v 20kW induction motor from it. The documentation I had said my generator was 3-phase but I just found out it's actually a single-phase output!! Damn. Any ideas how I can connect that to the motor and still run it at about 20kW of power?

[@aqeelalmousawi1500]

A few mistakes in this video regarding the magnetic field and calculating the 3-phase power @9:14

[@alparker7686]

What do you think the mistake was?

[@moulies2600]

Apparant power calculation formula(only magnitude) is correct

[@ZZZZ-zg3zb]

@@moulies2600 - dude he already explained the phase portion at the start of the video

[@stoobydootoo4098]

@@alparker7686 multiplying by 1.732 twice, in the power calculation.

[@giovannibaiocchi4356]

Mistake in 9:18 !! 2x1.732?

[@Automationacademytv]

Thanks for sharing your knowledge very informative, it inspired me to focus more making electrical video

[@omerabdalbage1207]

I am an electrical engineering student. What advice do you give me to improve myself and understand electricity?

[@Ryan-hr9hw]

Touch it as much as possible

[@raghukancharla6004]

Most enlightening video

[@2LZA3EEM]

Really one of the best explanation but what is r3 ??

[@jovetj]

The _radical symbol_ *√* is NOT an "r"-it is a mathematic symbol. *√3* means _the square root of 3._ Or, _3 to the power of_ ½. *√3 ≈ 1.7320508075688772935274463415059*

[@RubyRhod]

Altough the information in this video is completely correct, still one question was not answered: why 3 phases? why not 2, 4, 5, 6? why 3? And there is ONE major reason why 3 phase power is the way to go and the reason is the same why 1, 2, 4 phase power sucks. 5 phase power supply would have been the next choice. why? because power output over time is constant with 3, 5, 6, 7, 9 and so on phases (uneven numbers and any nmultiples of those)

[@ahmadbazzoun7481]

kzbin.info/www/bejne/fqK9paOqfdN2aKs

[@RubyRhod]

yeah.. that video doesn't explain anything, because the numbers seem to be chosen arbitrarily. so.. no real background there. again: after 3 phase power the next possible number of phases would have been 5 for the reason of a steady power output. but it can be explained quite easy why 3 phases were the way to go - there is no need for a 4 minute long explaination.

[@D4V1D83FY]

Hace mas de 100 años, en los inicios de la electricidad, se probaron sistemas de varias fases, pero el sistema que venció a los demás fué el trifásico.

[@alparker7686]

Here's a simple answer - the cost of copper. The detailed answer is a very technical analysis of cost of additional copper for each phase versus the increased "performance" of more phases.

[@RubyRhod]

the need for an alternating current with constant power output (and not any sin-wave power!) came from electric locomotives. they would slip with a power peak coming for example from a single-phase sin-wave power. when slipping, the friction reduces a lot limiting the capibilities of it! but with a constant power output the trains could be built smaller and more efficient. and again: 3 phases, 5 phases, 6 phases, 7, 9, 10, 11, 12, 13, 14, 15, ..(any uneven and multiples of those uneven numbers mentioned before) have a constant power output over time. and obviously when they all do the trick why use more than 3 phases? wouldn't have made sense in any way (yes, cost, but also complexicity). always think of the histrory of the technical system you have in front of you and electricity wasn't always for wide public use! then tesla and westinghouse had their stupid fight over AC vs DC is was already decided in europe to use 3 phase AC. that's what noone from the north-american continent seems to know and maybe they just don't want to know..?

[@thomasthoenes3171]

Thank you for this very detail video.

[@mikeymcmikeface5599]

The clockface was both unnecessary and confusing. Why not print degrees when talking about degrees?

[@australianjames1114]

I had trouble understanding 3 phase but i instantly understood what you were saying & why ac asalates

[@postholedigger8726]

The windings of a 3 phase generator are 120 degrees apart. It would seem reasonable that the power coming from a 3 phase generator would reflect the 120 degree locations of the generator windings. It would be an interesting experiment to wind a generator with the coils located at different degree locations and observe the phase pattern david

[@bryanst.martin7134]

I read a paper on 5 phase systems a decade or two back. Very interesting, and extremely smooth operating. Imagine building a Bridge Rectifier for that. Tremendous torque.

[@الديسي-س9م]

Bryan St.Martin can you give me the name or the link of that paper

[@Exceltrainingvideos]

Great video!

[@randalljones58]

When a capacitor goes bad, you can start the motor by rotating it. Since 3 phrase always has a flow of energy, no cap necessary.

[@rondeffely9494]

Capacitors are only used in a single phase motor to create an artificial phase

[@jessstuart7495]

0:35 Those 3 sinewaves are 90° apart, not 120°.

[@johnberry5275]

I was hoping he would talk about how the Utility people go about routing Three Phase power through a town, versus how they go about routing more ordinary 220vac Single Phase power around a town.

[@โชคดี-ฌ4ง]

@6:19 phase one is at the wrong place, is 120 degrees behind. It should start120 degrees earlier.