Transformer basics--theory and code

This video shows the fundamental concepts of transformers. It discusses magnetic induction, resistance, reactance, voltage, and current. It also goes into the NEC requirements for transformer and conductor overcurrent protection.

[@johnstorms3324]

You are doing a great service for the electrical community sir. I appreciate what you are doing. I feel smarter after watching your videos.

[@sparkee1965]

Ryan, your level of teaching is the greatest!! Keep up the good work!!

[@earthelectricinc.154]

The last time I saw a transformer demonstration like this was in 1997in trade school at Atlantic vo-tech , Fort Lauderdale. Thank you for that demonstration and excellent commentary. Great job Ryan!

[@nv7620]

Saw it there from Steve Owens RIP

[@1375stickboy]

Saved to watch a few more times to absorb everything.

[@electricity22]

Great videos. I appreciate the content, humor and style you use to get the code information across.. I recently passed my electrical inspector exams here in New Jersey. The big lesson from my 25 years as a contractor is that you should never stop learning.. Thanks.

[@rafg123456789]

I can't thank you enough. You clarified even for a beginner like me. I love how you show everything with great examples and pictures. It's as if I am doing everything practically. I never get tired of watching your videos. Thank you very very much. God Bless You!

[@Reynaldogarcia-kh2rv]

Your the best at explaining everything. I swear out of a million electrical videos I watch on KZbin I always understand things better from you . Thank you 🙏

[@dacrispytaco691]

Thank you for these videos they make a world of difference for all of us

[@GoCoyote]

Having gone through an IBEW apprenticeship, the two spools of wire is the best basic demonstration of a transformer. It really gets the point across.

[@mitchmaulik5932]

I waited for the wife to go to bed, so watching this at 1030 at night.. and not bored at all.. and wide awake.. you do such a great job and I really enjoy watching your videos! Thank you as always

[@jasonblaha6891]

I'm a 3rd year apprentice in California. Thank you so much so putting out these free videos because I need to rewatch multiple times

[@V21IC]

Why do I feel that back into electronics engineering again talking about AC circuits and phasors? This video is like a gold mine of knowledge and technical information!

[@michaelcostello6991]

Great demo showing the effect of reactance by using screwdriver and heavy spanner . Heavy spanner gives more induction/reactance so less current.

[@LearningInVR]

i watch on my phone for 3 minutes and i def got this one saved for later, cool demonstration

[@local631]

Awesome, thank you very much for that straight forward explanation with actual real world examples and sizes that most people will need and most likely will encounter. I am a DIY kinda guy and your NEC System Grounding and this class really explained how to and why to install systems the right way, more importantly how to understand what the right way actually is.. again Thank You Very Much and please keep up the good work. God Bless You Brother, And Have A Great Day...

[@obrigadoamigo]

Great stuff! Great examples and well presented.

[@billyhickman1591]

Ryan, from my heart, thank you 🙏 so much for your videos. You're absolutely my favorite KZbin teacher thus far. The way you break everything down and simplify everything making us think of what you are teaching and the visual aids is amazing. I smiled all the way through this video. I check daily for your next video lol. I'm eager to see them all.

[@RyanJacksonElectrical]

Thanks so much Billy, thats so nice to hear!

[@highpowerelectricalservice2850]

The transformer video was on point. Very clear to understand ! You're doing a great job. Keep it coming.

[@behindbarbells]

Finally, exactly what is was looking for. Great video, thanks!

[@RyanJacksonElectrical]

Happy to help.

[@TheVinesettj]

Thank you so much for this material. You make it very easy to follow.

[@GC-wc8wj]

Wow.. Great explaination..

[@zabizeyaee8002]

Thank you Ryan. I am learning a lot from you. Great instructor.

[@electricalron]

Love that 3-phase math trick (5000/ 120). Never heard that formula in a classroom before.

[@RyanJacksonElectrical]

I remember the first time I heard it. Seriously blew my mind! I've had so many people thank me for teaching that. It's a concept that just isn't taught.

[@mrfrenzy.]

I've been using it (secretely) for many years but never seen it mentioned in any literature. It's just common sense but not commonly used for some reason.

[@lakeleyvas668]

This is great. Going to suggest the union hall show some of your videos to the school.

[@johnkulpowich5260]

It's always good to review. I wish we had the internet 50 years ago. Sitting in my home spare time going to class not wasting time in traffic or going to a class. Next class should be on V F D

[@leonciocarrillo9186]

Excellent explanation 👍👍👍

[@intheskymusic]

Best explanation of transformers on KZbin 👍

[@omartirado730]

Salutes from IBEW Local #569 San Diego, CA. You’re a great teacher!

[@m-bigzadaproductiontm7262]

I appreciate everything, this is some thing I was looking for.

[@gh2110]

I’m a master and still learning” don’t you stop 🛑

[@johnkulpowich5260]

I'm in the trade 50 years love reviews. Always learning.

[@AlfredoSuarez-rl3qf]

Hello Ryan. Tanks for this master class.

[@davidjackson4112]

Ryan, Thank you for your time. Greatly appreciated.

[@fayiznalu8411]

Good demonstration...!!!

[@HuyLe-mx6to]

Hi Ryan, I've seen you in Mike Holt's videos, and I'm very impressed of your knowledge. I've watched almost all of your videos. They are all great! I'm looking for practical info regarding Title-24 (Lighting Requirements, or diagram for electricians or general contractors). I don't see alot of videos related to the Tittle 24 code, and I think it's will be very beneficial to electrician as well as general contractors. Thanks again.

[@ThePlantagn]

Ryan your demos are great. I really appreciate your vid’s.

[@camoapajafa]

Good work Ryan, I see you learned more on Mike Holtz Seminars lol, like Mike holtz Said in one of the vídeos. "Mike holtz is going to disappear one day", we need more Leaders, and i see you are one of them, Congrats, and keep on going. Thanks l like to watch your videos. Atte. Jorge Flores.

[@erasmolopez5679]

Do you have a topic motors related; because I love the way you do the presentation

[@stans5208]

Very educational. thank you, although I'm going to have to watch this at least one more time to grasp all of the numbers you throw out . Which is great cause I can always go back if missed anything. I've been a sparky for a few decades. IBEW Local 3 NYC. I have worked in many highrise buildings, subways,bridges, tunnels,manholes. You name it I've been there. Many times we work from blueprints that were designed by engineers architects and buttheads. With that said I normally don't have to carry a code book in my tool box. I'm more of an installer rather than a designer. Your 1 to1 ratio or 480 v to 480 v transformer s I have used in elevator machine rooms. I questioned the elevator guys about that and they told me that's how they get clean power for their electronics and computers . We still put 2 disconnects because the specs call for it. You have have to give the customer what they pay for regardless the code,unless it's illegal. We also use greenfield or sealtight to change over to go into the transformer. (For vibration). Makes no sense because the coils are mounted on shock absorption pads from the manufacturer. So if mounted to the floor we have to put rubber pads and if hung from the ceiling we have to put spring shock absorbers. ( With flex conduit). Thank you

[@alvaroyucuma6090]

I am writting from colombia. What a great job mister Jackson. God bless you.

[@RyanJacksonElectrical]

Thank you sir!

[@jaredhouston4223]

I'm so glad I found your channel

[@darrellallen5327]

Badass teaching

[@brokenarrow7037]

Ryan I will finish the trim in ur house if u come finish my electric! I love ur videos. Thanks and please keep making!

[@gh2110]

Ur great” u touched up on a lot of mike misses” don’t forget generators” sum guys still don’t get it.

[@regularguy2943]

That is the best explanation I have ever heard

[@benjets9345]

That’s interested and simple to understand

[@MrMaxyield]

This video has become mandatory viewing for my apprentices and recommended for my colleagues in the service department... Sometimes a back to basics refresher is absolutely advantageous... Simply superb sir, we thank you. 🫡

[@nayivisdenis1401]

hi .Ryan we need a video about Objetionable current and what is the best point to bond neutral and ground in the large swtich board in building.CASANOVA EC

[@AllAroundHnadyMan]

Excellent - thank you

[@ernestperino9334]

Ryan you are a great teacher love your videos

[@miguelac6872]

Ryan I watch electricity videos in Spanish, but nothing compared to this teaching you give us. Thanks God I learned English. I seems to me that I have seen you working with Mike Holt.

[@RyanJacksonElectrical]

Hi Miguel. I used to write books for Mike, and I probably did 50 or more videos with him from 2005-2017.

[@miguelac6872]

@@RyanJacksonElectrical Awesome. Ryan I do have a question. Why does not the NFPA 70 NEC add the nomenclature TN-C-S to identify the type of grounding system the NEC implement from the other countries grounding systems TT, TN, IT, TN-S TN-C? Like I feel the American grounding system does not have a particular, peculiar or unique way to be identified, hence a lot of confusion is created in regards the american system in other countries. I sent the proposal to the NFPA, Do you think they will make the update? Because the grounding systen the NEC uses corresponds to a TN-C-S earthing arrangement or configuration. IEC 60364. NEC 90 C 1

[@RyanJacksonElectrical]

@@miguelac6872 Honestly, I've never heard those terms.

[@mcarroll598]

Excellent job Ryan!

[@electricianed1076]

Ryan, it's great to find you here on KZbin, doing this kind of work. I first got to know and appreciate you through your work with Mike Holt.

[@jarrydee2799]

This is gerat. Thank you so much for teaching us! I am going for my masters test in a few months in Michigan and dread having to study this codebook again..

[@RyanJacksonElectrical]

Good luck!

[@ronbonick4265]

great info Thanks Ryan

[@Lionofjudah308]

Love the content thank you for your dedication and hard work to others greatly appreciated.👍🏼🇺🇸

[@ed6837]

Awesome video!!!!!Thank You!!!!!

[@edwinlandy]

Thanks! This helps a lot. So, a transformer is like an automatic transmission torque converter where the transmission fluid is electromagnetic field. It's crazy that either one of them work.

[@kalami171]

Thank You Ryan! You are a great instructor

[@sohailjanjua123]

Hi, I like your lecture . Thanks

[@poolsdoc9178]

Great video

[@briangaquin1021]

From what I have read inrush currents last a few cycles, the maximum inrush is often touted as 10X the rating of the transformer, in my experience 4x to 6x is normal for a standard off-the-shelf dry type transformer. Where we have seen inrush as high as 14 times is with fast transfers of ATSs' with no in-phase monitors. The ATS transferred back to the utility with the two sources out of phase, which resulted in a very high inrush on the utility source.

[@hangngoaigiare]

Thanks Ryan great info. It’s really help you always have real world pictures not a drawing. That makes it so much easier to understand your presentation. Do you have info on the transformer grounding and bonding on your other video? Would you do a video about sizing the transformer for different applications. Specifically for motor and rooftop HVAC equipment. VFD On HVAC equipments don’t work on 3 phase delta high leg so it need a transformer either for vfd motor only or the whole HVAC unit.

[@GreyGraves]

Awesome video Sir!

[@pepemorgue]

Hello there! Thanks for sharing, im currently studying at LATTC and this info is very helpful!

[@RyanJacksonElectrical]

Glad to hear it!

[@kabandajamir9844]

So nice

[@mikecole1703]

Thank you Mr. Jackson m

[@ThePixraider]

The screwdriver is longer than the ratchet, when you used that as the core your amperage increased because you coupled more coils in the primary.

[@lawtonsegler1923]

Keep’m coming!

[@arvinmiranda7855]

Thanks Ryan Jackson I really love this topics

[@kevinkeating7920]

Very informative thank you!

[@luisdorta9780]

👏 Nice!!!

[@chadg6874]

27:25 I definitely want to magnetize my socket wrench now lol

[@im1-z2x]

Literally my whole 2nd semester. Trade school class , in the first 10 minutes wow thank yoy

[@RyanJacksonElectrical]

Thanks!

[@jaxalexander2154]

Excelente trabajo

[@jasonokane496]

Really informative information sir. I really appreciate the knowledge you bless us with. I always like to further my knowledge with continued education. I’m curious do you offer any online classes?

[@davem5392]

one point if you can clarify i see in my factory many single phase 480 to 120/240 transformers so the panelboard must have a main or a fused disconnect before it cause its not single voltage. Transformer secondary cannot in this case be protected by primary correct? Or for almost any separately derived transformer power system in Industrial or commercial?

[@michaelcostello6991]

At 17:39 in video you measured the max current. Was this the inrush current or normal steady state current ? Are they the same here as you just have a spanner so poor induction taking place ?

[@miguelac6872]

Awesomeeee

[@aesajoma]

Nice job

[@robertochavez6221]

Thanks a million times for sharing!

[@mitchellbarron5433]

I liked your video so much I tried to make a transformer like yours but it trips the breaker because it’s a short circuit. How did yours work? I wired a coil of #12 thhn with one end to neutral and one to hot and plugged in to a switched power strip so I could turn on and of quickly and then another coil to lamp holder. It trips instantly without ever staying on at all. So are you not using a breaker?

[@RyanJacksonElectrical]

I am definitely using a breaker. It will pull a lot of current, so you can't leave it plugged in very long. I don't leave it on for more than 10 seconds.

[@bigkkyle79]

ok i got it ,,,i kept reading the other comments and you explain it think you

[@bryancontreras4541]

Thanks Ryan , like always great stuff man!!!

[@johnquilla8236]

Impedance, resistance, reactance do you have an explanation of them? That differentiate them

[@RyanJacksonElectrical]

Impedance is the total opposition to current flow in an ac circuit. It consists of resistance and reactance. Resistance is a physical property of the wire, and reactance is (for this demonstration) a function of the shape of the wire, that being a coil. It's a bit more involved though, and requires more explanation than I could do in a KZbin comment. Sorry

[@johnquilla8236]

@@RyanJacksonElectrical well said, I’ll just do my research about reactance. I came across Lenz law about eddy current. I’m subscribing to you right now

[@carultch]

@@johnquilla8236 Resistance (R) is a property of a component that dissipates power when subject to a voltage difference across it, while reactance is a property of components that store energy and release it at a later portion of the AC cycle, like inductors and capacitors. Resistance (X) only depends on the geometry, temperature, and material of the resistive component. Reactance by contrast, depends on both geometry and AC frequency (f). For a capacitor, reactance depends on the capacitance (C) as a measure of its electrostatic size, and equals -1/(2*pi*f*C). For an inductor, reactance depends on the inductance (L), as a measure of its magnetism, and equals 2*pi*f*L. Resistance causes a voltage drop across a component, while reactance causes a shift in phase. Impedance (Z) is a special way to combine both reactance and resistance together, in order to analyze series and parallel combinations of any of the above devices. It enables you to "black box" these components as impedances, and add up the impedance terms as if they were all resistors, using your series and parallel formulas for combining series and parallel impedances. Then you substitute the expression for each component's impedance to evaluate it further. Mathematically, impedance is an application of complex numbers, where resistance is assigned to the real component of the number, and reactance is assigned to the imaginary component of the number. In pure mathematics, the imaginary unit is called "i", but this is spoken-for to stand for current. So electrical engineers opt to use i's next door neighbor, and call it "j". Impedance Z = R + j*X. Magnitude of impedance is a Pythagorean theorem combination of R and X. You can think of R and X as perpendicular vectors that add up to Z.

[@michaelsmelser1101]

Dayum Ryan Jackson!! Where were you when I was in 2nd year??!!

[@fisforfriendship6093]

53:22 mark i thought you could on 3 phase systems cheat by dividing the kva by 3 as well as the primary voltage by 3 then devide kva by voltage for current? i got 468 amps

[@uphelectricpablo2149]

Good job

[@sebastianruiz4728]

How does that first spool of shorted 12 awg not trip the breaker?

[@RyanJacksonElectrical]

Inductive reactance.

[@TheKevinbabineaux]

Great stuff. You the man

[@DBABN7]

Bro you and mike holt I hold to high regards. Do you have any tips on what I should do to attain more knowledge.?

[@ThePlantagn]

Ryan did you measure the voltage on the secondary?

[@s.pursell8901]

So all boilers, steam generators or what ever generates pressure is condersided a pressure vessel. All pressure vessels are rated by horse power and them converted into mega tons and so on. I must have missed it but when you showed the placard for the boiler I seen neither the horse power or the BTU "British thermal units". Do you recall the horse power of this boiler?

[@miguelac6872]

Lets say we have a single phase 37.5 KVA transformer, (240,120 V ) the secondary can deliver 156 A total, the question is, when a ground fault occurs between a hot and the EGC, how come the amount of current is way to higher than the nominal current the transformer can deliver 156 A? I know that the EGC is a low impedance path but where does that super extra amount of current come from?

[@RyanJacksonElectrical]

The thousands of amps that you describe, which are the result of a short circuit, is what we would call the "available fault current." That number gets smaller and smaller the farther you get from the source (utility, for example) because you are adding resistance with the wire and transformers that we are installing. The number is high because the impedance of a direct short circuit is very low, but, again, the farther you get the lower the current will be (generally speaking). If you search for "bussmann fault current" you can find a lot of good information, as well as a free online app that you can use to see how it plays out.

[@miguelac6872]

@@RyanJacksonElectrical Thank you very much.

[@Riffs24]

12.5 Amps is greater than 9 amps on the secondary it should be 125%. @52:15

[@lesterwatson8519]

Great video!! I have noticed that most iron cores in transformers are laminated is for heat diapason purposes?

[@collins3244]

Hi Ryan, how can I get the DeWalt reference book.Pdf

[@brandonrippeonphoto]

Does the wire coating affect anything?

[@spelunkerd]

This was very helpful, and interesting. I'm wondering what current flows in the primary when the secondary is not hooked up. They say with a manufactured transformer, it should be no more than a few percent. Does an open secondary causes a dramatic increase in impedance because of the induced voltage drop across the secondary windings? If you were to scope out the secondary voltage, would there be a huge back emf voltage spike because there would be nowhere for that secondary current to go? Presumably a home made transformer, with inefficient energy transfer and weak core, more primary current will trickle through when secondary is open?

[@jlmm3968]

If you are using flexible metal conduit on primary and secondary side do you have to use bond bushings for flex , I’ve seen some people bond both primary and secondary , I’ve seen people use no bond bushings at all and still pass. Please tell me code section that states either or thanks for your videos

[@RyanJacksonElectrical]

Only if the knockout is concentric (or otherwise impaired) and the voltage exceeds 250V to ground. See 250.97.

[@bigkkyle79]

im a little lost when i do the 3 phase transformer math, i get a different answer, i get 225 kva/480*1.732 = 811 Amps What am i doing wrong