What's inside a Transformer?

[@stevewhite6252]

I am a retired electrical engineer whose hobby is building high voltage equipment such as Tesla coils, Marx generators, Cockroft-Walton multipliers and pulsed power generators. I just wanted to let your viewers know that we high voltage hobbyists sometimes use pole transformers as step-up transformers which is of coarse the opposite of the way that they are intended to be used, however the transformer doesn't care if its being used as step-up or step-down. I use a 10 KVA 14.4 KV pole transformer as a power supply for my large spark gap Tesla coil. It puts out 9-foot long discharges with 6.5 KVA of input power. Its always a big hit during Halloween with several hundred spectators.

[@dangordon1498]

I have a transformer for sale? Is anyone interested in buying it? What is it worth?

[@981porsche3]

Make a video of that thing in action! I want to see it 👍🏻

[@littleshopofelectrons4014]

@@981porsche3 I now have a channel. You can see it on my channel.

[@qua7771]

How can I harness free electricity from the either?

[@marcallen6987]

@@dangordon1498 Tree fitty

[@WarpFactor999]

Fun Fact: Water and electricity DO mix! But only if it is ultra pure. Large power stations circulate super pure water inside the conductors used inside the generator motor windings to keep them cool. The generator windings are large 3" thick copper bars formed into windings with a hollow core for the water to circulate inside. (Re: 10 years as a trainer at a twin 1150MW power plant.)

[@MarkFunderburk]

Indeed while "water and electricity don't mix" is pretty decent advice for general application, pure water is actually a pretty good insulator. The problem is many things like to dissolve in water (like salts) and those ions or even just particles floating around will make the solution conductive. In fact, a common way of measuring water purity is with its conductive-ness. Typical antifreezes will probably have additives that would probably make it more conducive and of course water will corrode various metals in a transformer thus becoming conductive and just causing damage from the corrosion. And out on all that the relatively narrow working temperature of water is also problematic. Anyways, there are lots of reasons why oil is preferred in these low maintenance systems, although water is actually a better coolant than oil.

[@boblatkey7160]

Thanks father, but I'm not sure anybody was asking.

[@kdawson020279]

I'm not sure why it matters, the resistance of water is enough that unless it's strongly electrolytic, it works well for cooling as accepts heat well. Typically, though, water cooling is best for indirect exchange and oil for direct exchange of heat, due to the potential for the water to become electrolytic through contamination or electrolysis caused by the remaining impurities giving off oxides.

[@Redbird45]

Electricity isn’t conducive in distilled water The only reason water is bad to mix , electricity is because of the minerals and that help conduct electricity.

[@wb8ujb]

Years ago, had a tornado touched down in the neighborhood. Sitting on the porch some time after the storm, I could hear a frying sound across the road. I walked over and could hear the transformer on the pole boiling. I called the power company and the operator said, "there is no chance of it blowing up". I said oh, that's good it's close to our house. After an hour of cooking, it was starting to change colors. I called again and told them what we were observing. Again, no chance it will blow up. So we went back to our chairs on the front porch. Shortly after that, the transformer started venting white smoke. Then a large bang and the top of the thing went up in the air about 50' . I called them back and said, tell the crews they need a pot for this report. :)

[@cobrasvt347]

Nicely done. 👍 for anyone wondering ONAN is a naturally cooled by air transformer and ONAF is air forced cooling by a fan and usually having find to radiate heat out away from the transformer core.

[@b3j8]

I can remember back in the mid 1960's going to our local "City Dump" w/my Dad to drop off some junk from clesning out our garage. There was one of those transformers laying on it's side in a pile of brush and other crap. All the concern over PCBs came later.

[@NealB123]

I saw a transformer explode once when I was a kid. This was back around 1980ish. I was mowing grass in our front yard and just happened to be headed in the right direction when it happened. The transformer was located about 50 yards away. The top blew off, a big fireball shot out of it and then descended all the way to the ground scorching the grass. The transformer continued to burn until the fire department eventually hosed it down with water. It was quite an impressive little BOOM.

[@edwardmoore5325]

You weren't heading in the right direction that would be the opposite direction.stay safe people.

[@edwardcornell1263]

What fascinates me, is when a transformer is shorting out and turns into a light bulb until the linemen turn off the power or a fuse of somesort disconnects the circuit. Had a storm a few years ago. Lost power. Linemen tried to bring power back, but a transformer turned into a lightbulb, then after they fixed that one another one down the road had the same issue. So instead of getting back on at 8pm. The power came back on at 10pm.

[@Craig1967]

I just wanted to say thank you for all the information you are presenting. Real world stuff that you can't find anywhere else. Books and Internet searches always give such dumbed down generic theory with no specifics. I have worked with electronics since I was a child, and always wondered how you guys do your jobs so well, and how it all works. I love watching your videos. Keep them coming!

[@ph11p3540]

All this time I thought thousands of really pissed off pixies lived inside those transformers. Never mess with a tiny little angry pixy ferry.

[@SomeTechGuy666]

I'd love to see a video that had pictures of various pole/tower configurations along with a description of what the voltage of each is. 4160, 7200, 25KV, etc. I'd love to see some 3 phase feeds into commercial customers and how the line voltages get down to the various 3 phase voltages - 208, 460, etc. Ever work on wind turbine feeders ? Great channel.

[@duhacekfamily]

My son was a first year apprentice lineman The back feeding of a improperly installed back up generator is exactly what happened to the Journeyman/trainer he was working with he was severely injured my son had to rescue and bring him down sadly he didn’t survive

[@aerospacesystems8658]

Sorry about that. Wish you can get some strength and peace.

[@davidd1395]

It’s never dead till it’s grounded. Lineman have to keep this in mind every second every day.

[@TCGProductions03]

@@davidd1395 Yup. And if it's not generators, it could very well be induction from other energized lines, or even faulty UPSs that don't disconnect from their line side when they switch to inverter power.

[@BigDaddy_MRI]

These days, those little power supplies are not using transformers. They are switch-mode power supplies. They take anything from 90-240vac and using switch-mode technology make almost any voltage you need. From 3.3-50vdc and the output is regulated and over-voltage and over-current protected. I use a lot of them in my projects. I have a Masters Degree in Electrical Engineering. And I’m enjoying your channel very much! Thank you!!

[@micsky99]

Even switch mode powersupies have a transformer so he is technically right.

[@BigDaddy_MRI]

@@micsky99 Yes that’s true. But they are typically high frequency. So, a 10 amp switch mode power supply internal transformer is “tiny” compared to a 10 amp 50 or 60 hertz transformer. And some switch mode power supplies don’t use a transformer at all. Some small power supplies only use a fractional coil on a powdered balun. These are charge pump type, like an Apple charger for example, and during the pump cycle, a mos-fet will charge up the coil, then when off, the stored charge will keep a capacitor charged. Again, these run at about 600KHz to around 1.2 MHz, and are called ‘buck’ converters. I have a 40 amp 5vcd switching power supply, and it does use a small transformer, but it’s tiny, and weighs almost nothing. Another reason most passenger aircraft use 440Hz. The transformers and motors are smaller and lightweight compared to 50/60 Hz transformers. Thanks for making that correction. Appreciated!

[@danjarvis6980]

@BigDaddy_MRI : I have a propensity for digression but will endeavor to stay on course for the sake of brevity. Retired now but when I was doing control work on production machinery I had to install small XFMR ( Step Down 240/120 PRI -Sec 24 Volt A.C. this XFMR had a feature called " FOLD BACK " . In other words you could load the secondary side to it's rated maximum, but if the secondary was shorted it would actually draw less current shorted than when fully loaded. Any idea how this was accomplished ? I had 4 yrs. theory as a journeyman wireman, NOT on an Engineering level so I can handle some basic theory if the answer requires it. But if the answer requires a visit to some guru in a Himalayan cave quoting Napier Logarithms, calculus and 3Rd Harmonics, I will respectfully withdraw the question. Working with an engineer on a generator one night, I found a wire disconnected. I asked.." Bob, how do we write down what the problem was, a loose wire ? His reply " no not a loose wire " " there was a failure to maintain contact integrity of that wire " Engineering eloquence at it's finest !!

[@selske23]

Worked as an industrial maintenance technician, had a power outage on one of 6 30kv transformers in the factory. When our crewchief tried to power it back on to see if the fault had gone away, it blew up, taking out the power to most of the city around us. My coworker and I have never been happier to see big armored doors hold up and protect us from the explosion, though they were bent a good few inches. Never seen more firefighters in my life as when we called in "explosion and possible fire in high voltage transformer". Ears were ringing for days after that

[@Bobsdecline]

Oh wow that sounds like a really close call!

[@selske23]

@@Bobsdecline Yeah, really illustrated to me how you simply can't make a decision like that without knowing everyone is clear and safe.

[@Bobsdecline]

Definitely! Even when we energize new buildings we go inside and ask everyone to leave the electrical room while things are powered up!

[@jovetj]

@@Bobsdecline Arc flashes are NO JOKE. I'm surprised they don't train you to look away from closing or opening cutouts or switches.

[@GypsyHunter232UK]

I gave my old 86 Yr old mum one of these for Christmas..she was truly shocked..yours sincerely from the old qeer corrupt uk 🇬🇧

[@oldrudedog]

I worked for Shell oil in the 70's and we made Diala AX transformer oil. We made a batch to go to the Philippines and it had moisture in it and every one of them blew up when activated. They check the production every 15 minutes to make sure there is no water in it.

[@FF5754]

Very cool video! I use to work in substation, now I'm in generation but anyways, we would clean our insulators with water from the power plant across the street. The substation can not be shut down because of customer demand on it. Until that day I thought for sure water and electricity do not mix. Turns out, they can but the water is not the danger, it's the minerals and contaminats in the water that conducts the electricity. So, very weird feeling washing insulators on an energized tranformer and breakers. Demineralized water or demin water is 100% safe to use for this process. Corn cobs that have been crushed to a fine media also is an excellent cleaner of porcelain insulators in an energized environment. Just be very aware of approach distances because they don't change and you can be killed quick.

[@beatsbypher]

Hmmm, transformers,... "More than meets the eye". Lol, someone had to say it. ;)

[@MW-sw7so]

Ha, dang it i was gonna say that too!👍

[@Deadbuck73]

That’s awesome!

[@KawaiiSoulB42]

MY lord

[@walterdayrit675]

Yup, someone just had to say that! 😂

[@chaseman94]

Autobots wage their battle to destroy the evil forces of the Decepticons!

[@8squarefeet190]

Noice! While I was trained in electronics, and know what a transformer does.... I'd never seen the inside of a big one like that before. You should do a more detailed version on why home generators can be so dangerous to lineman working on downed lines. Most people don't realize they work the other way..... Keep the videos coming.... but be safe!

[@Riverrockphotos]

Yes people like to use suicide cords. You should have the genrator isolated from the power pole.

[@edwardcornell1263]

Home depot carries a selector switch for GE electrical boxes. Run a circuit to the generator. This kit locks those breaker off, until you turn off the house main breakers. Then when you want to go back. The generator breaks have to be turned off first before turning back on the main.

[@AndrewMoizer]

Totally agree on the generator and back feeding request. During the big Ice Storm '98 here in Eastern Ontario I was hooking up a lot of generators. We had a hydro inspector who lived in our village and did a lot of work helping out. He was insistent that if I was back feeding a panel that I disconnect the service neutral as well as having the main breaker turned off. Was easy to do when the power grid was down, was a little more tense connecting things back up 10 days later! I notice that the Square D generator panels available at HD use parallel 3 phase breakers to switch all three lines, which I thought was a pretty clever solution. However, my son just had a Generlink unit installed in the meter base of his house and it doesn't switch the neutral, at least as far as I could tell when hydro had it out when the new service was finally getting connected. So I am kind of wondering what's going on there. And I can tell you that after going through the Ice Storm I have immense respect for all the linemen who worked so tirelessly to repair all the damage. So the last thing I would want to do is put them at any risk if I have to use my generator. Right now I just unplug things and plug them into the generator so that things are totally separate, just to be sure.

[@jovetj]

You might like this video: kzbin.info/www/bejne/nWioZ6qAbM1mZsU

[@Cwra1smith]

I have an interface which uncouples pole service feed when the generator starts.

[@firesurfer]

During a large storm, I heard a large crack type explosion. I knew immediately the transformer got hit by lightning. The entire area was blacked out for a day. It was really close, like less than 200' away.

[@Ry____]

“What’s inside a transformer?” Magic smoke, and if you let the smoke out, it don’t work no more. -Electrical Engineer

[@tc6818]

Electrical manufacturers put the magic smoke in.

[@tchevrier]

We've had 3 transformers blow in our neighbourhood in the past 5 years. Pretty spectacular when they go. Blows the entire top of the pole off and starts it on fire

[@simontay4851]

They're obviously under rated for the load on them, which makes them overheat.

[@tchevrier]

@@simontay4851 Possibly, but I suspect it has more to do with the fact that each one has blown during a thunderstorm.

[@deang5622]

@@tchevrier So no spark gap protection?

[@farpointgamingdirect]

"Water and electricity do not mix..." Pure water is an insulator. What causes conductivity in water are the minerals which of course carry stray ions which in turn conduct electricity.

[@jfbeam]

With a high enough voltage, everything is a conductor. (even pure water)

[@ChrisSmith-rm6xl]

It isn't even as good an insulator as the oil is even if 100% pure. 100% pure water has a resistance of182,000 Ω.cm at 25 °C That's a quarter of an amp at 7,200V, and it never stays 100% pure for long.

[@michaelbushey3200]

Our electric grid is so old We still have the old black transformers with PCB ‘s in them in our area.

[@dandearman2871]

Ah. The smell of PCBs in the morning. You can tell if a transformer has PCBs by the smell.

[@Rebel9668]

A few of the ones around here are the black ones. Back in 1998 I lived in a very old home in Tennessee that had stood empty for many years. It had one outlet in each room and no 240 except for at the old fuse box. I added 240v wiring to it's unused cartridge block and got a couple of cartridge fuses for it so I could use an ancient 240v radiant "4 stack" floor heater. Turned it on and everything was fine for a few minutes, then every light in the house went out. It was nearly 11pm by then, so I just went to bed and called up the local bpu the next morning. They came out and checked and of course it blew the breaker in the old transformer on the pole. The linemen were surprised as they said they hadn't seen a transformer like that in over 30 years as all the rest around there had been replaced. From the ground it didn't look much larger than a large coffee can. I came home from work the next day and saw a new large light gray transformer on the pole, lol.

[@johngrattan302]

Thank You, Very informative for a residential home owner👍

[@thomasdressler9939]

When I found out my toaster wasn’t water proof.i was shocked 😳

[@jed-henrywitkowski6470]

Lol.

[@Whoflungpouu]

When I found out my toaster wasn't water proof .i was shocked 😳

[@Whoflungpouu]

Lol

[@deang5622]

Now that's why you need an RCD! 😋

[@toddchikigak6339]

😂😂😂

[@dennisnorsherd523]

i already knew it was a liquid base like maybe a h20 mix but ya! oil does make more sense. thx for taking us on the job today! keep safe!

[@Poppabill48]

Only 3 things I would like to add. on your "schematic" on the transformer can 240 volts comes out of connecting X1 to X3. Two, if arcing occurs under oil, acetylene gas is produced and rises to the head space. If an arc occurs in the headspace, that is what causes an explosion. Of course with Lightning all bets are off. The third and maybe the most important for safety is that before you take any lid off you vent the can. This is just 34 years of experience talking.

[@jovetj]

I don't see how 240V can come out of X1 and X3 since they're separate secondary windings.

[@boblatkey7160]

Thank you father

[@rickzielinski8612]

Thank you for sharing all your knowledge and experience with other lineman... Happy Holidays from Florida!!

[@laserhawk64]

Rural North Carolina here. Electronics hobbyist, jobless and disabled... amongst other things. Huge respect for folks like you, I work on stuff with basically battery voltages. What you do is more like workin on a Jacob's Ladder or the biz end of a Tesla coil while it's running. Not gonna lie, that idea scares me a little bit lol. Funny thing, the transformers around here, judging by the winter storms we have when it gets bad in January and early February, mostly contain sparks and fire :P makes one heck of a bang when they detonate, too... amazing what a little ice in just the wrong place can do! Seriously, though, a transformer in simple form is two coils of wire. Usually it's wrapped around a bunch of "laminations" -- thin sheets -- of what's called ferrite, the stuff that the little fuzz in those "Wolly Willy" toys are made of. It's a special kind of iron-based ceramic that's really good with magnetism. Because magnetism and electricity are really close to each other, when you have a big coil of wire in one spot, and you put power through it, it creates a noticeable magnetic field. (Technically, *any* wire lead with power is a one-turn coil, but that's not important here; you only have to worry about that with either high-tension-line kinds of power, or frequencies starting around that of microwave ovens and WiFi) If you have another, unpowered coil, nearby, and you jigger things up just right, you can power one coil from the other without the two being electrically connected. This uses what's called "magnetic resonance" -- the changes in the magnetic field in one coil, show up in the other coil, producing electricity from the magnetism. (For what it's worth, this is also how antennas for things like radio, TV, and mobile phones work, at least in part.) What Bobsdecline shows as "transformers" inside the house -- eg laptop bricks -- are somewhat more complicated devices known as switch-mode power supplies. Most early power supplies, regardless of whether they operated on AC or DC, were called "linear" power supplies, and they lowered the voltage being output basically by converting excess electricity to heat. Obviously that's not very efficient! A typical switch-mode supply takes advantage of something called "inductive kickback" -- you know how, when your air conditioner cuts off, your lights often get a little brighter for a split second? That's inductive kickback -- when you have a coil of wire, such as in the big honkin motors that run the compressor in your HVAC system or heat pump, and you cut power to that coil after it's been "energized" (had power put through it), as the magnetic field collapses around the coil because no more power, it creates electric power within the coil, going the opposite direction from the original power source. If you take something that can store electrical energy in it for a little while (we generally call that a 'capacitor'), and connect that to the coil, such that that bit of kickback gets stored in the capacitor, then by switching the coil on and off again really freakin quickly, we can add electricity to electricity inside that capacitor. That's the basis of how basically all switch-mode supplies work, from the ones that are in your laptop's charger brick to those little lightweight wall warts and USB chargers. _Heavy_ wall warts are often called "unregulated", but really they're _load_-regulated -- a simple transformer, and a thing called a "diode bridge" that turns AC into DC, and that's it. Because the more electricity you try to pull from a transformer, the lower the voltage coming out of it, for the most part (aka "voltage sag"), so-called "unregulated" supplies are designed very carefully to balance all that out, so that when your gadget needs 'x' amps of current, it's getting them at the proper voltage.

[@n2rj]

I am wondering when/if ever we will use switching power supplies in place of the big, heavy transformers we have now? Probably would help with heat and efficiency.

[@Jakek200]

I'd say probably not considering the added complexity and electronics of a SMPS which would likely be more susceptible to voltage spikes from lightning and heat (at least the semiconductor parts), not to mention it'd be converting the high voltage AC, to DC, and then back to Pure Sine Wave AC at that which requires a fairly complex inverter and lots of filtering. And finally there's really not much of a reason to replace the 'big heavy transformers' considering they're not really using up space that would otherwise be used by something else, as they are transformers are super simple, reliable and robust.

[@jovetj]

No. Why would you even suggest that?

[@65gtotrips]

Cool video...here’s the thing though, you say their ‘primitive’ yet there’s really no other way to economically induce current in secondary windings...

[@QueLastima]

Don’t think of it as denigrating. It’s primitive in that it’s basic. The way a transformer works is not mechanically complicated. That’s what I heard in the comment.

[@chrisgraham2904]

I well remember the electrical transformers when I was a kid that were filled with PCBs (polychlorinated biphenyls), rather than the environmentally friendly oils that fill them today. PCB's were banned in the U.S.A. and Canada in 1977 as a proven carcinogen. My city and local electric company used to collect the waste PCB oils from decommissioned transformers in tanker trucks and they would spray the contaminated oil over all the unpaved lane ways throughout the city to keep the dust down during the hot summer months. Growing up in a neighbourhood with lane ways behind every street and being kids that often played in the lane ways, the level of exposure is unknown. Our baseballs and soccer balls rolled in it and we carried the oil on our sneaker into every household. "Awwwww! the good old days".

[@NebukedNezzer]

in 1962 I was in electricity class in my high school. we took apart donated 3kva pole transformers. salvaged the iron, and copper wire. I made a battery charger and some others made welders. we sheared the laminations to what we wanted. threw away the oil. the wire was 16 gage on the 2400 volt primary and 1/4 square wire on the 240 volt secondary(center taped for 120x2).

[@okjeffy6581]

Wow how old are you

[@NebukedNezzer]

@@okjeffy6581 76

[@stargazer7644]

You're lucky the polychlorinated biphenyl (PCB) oil used in those old transformers before 1977 didn't kill you. It's nasty stuff.

[@fredflintstone8048]

Thanks for the insight. I never knew. I was raised to think that a transformer was a car that could turn into a fighting robot and back again. Who knew there was another use for the word?

[@N1gel]

Such a shame you didnt detail the actual terminals purpose or the terminals connections to the secondary windings. I am assuming its just a winding with a few taps at 1 end? To adjust op voltage for length of line vs average current.

[@norcaldeemichaels]

I’m a Union Stagehand. After 25 years of solid employment, & at 45 years old, my industry has ceased to exist, with no firm answer on when anything will resume. “Maybe in mid or late 2021, there may be some events starting back” is the most promising line I hear these days. This is one of the fields I’m considering getting into.

[@sawyerandjackfucking]

I'm in the exact same boat, my friend. IA 680.

[@firesurfer]

I'm 65 and in the convention business, I was planning to retire at 67. It looks like early retirement for me.

[@pklongutoobe]

A switch mode power supply is not always a transformer. Some do have high frequency transformers and/or an inductor (which is basically half a transformer) in them, but not all.

[@stargazer7644]

What else is a switch mode power supply going to have in it?

[@HyperMario64]

A SMPS taking power from mains will nearly always include a flyback transformer nowadays. A power MOSFET is used to switch at high frequency on the primary side of course. If you are aware of any product plugged on mains that doesn't include a transformer (of any kind), I would be very interested. And even lower voltage DC/DC converters will need an inductor for buck/boost topologies and friends. The only case I can think of with truly no inductive components are some DC regulators like LDOs but I bet you some transformer stands between that and mains. And a LDO is not a power supply nor it is a switch.

[@slyspy9819]

Hey Buddy , I've been an Electrician for 36 yrs. now and I'm enjoying your videos and the other side of the Electrical trade we don't get to see .

[@spocksvulcanbrain]

Also check out the TV show "How It's Made" for the episode showing how transformers are made...

[@madmat276]

I like the break down.. how ever I have seen more than one transformer exploded not like the line break blow but pieces of hot smoking metal and lots of purdy colors and sparks and boy oh boy are they loud as hell when it happens.

[@GeorgeBonez]

I love this channel. It makes me so glad I went into Telecommunications instead of electrical. Well maybe that didn’t come out exactly right. Lol 😂

[@dennisammann9104]

Very informative, I had no clue what’s inside a transformer. Thanks for the info. 😁🤔

[@oldtimefarmboy617]

A direct lightening strike on a transformer can create a brilliant light show as well. Happened at a business I worked for. They had multiple transformers mounted on a platform that was mounted above ground between four poles. They provided power to several buildings including one that used three phase motors. Several of the transformers blew open sending flaming oil way up in the air. Southwester Public Service Company did a tremendous job getting new transformers put into place and repairing other damage. Fortunately business was slow at that time but they got everything fixed and running in about eight hours.

[@2fathomsdeeper]

In Tesla coiling, we call these pole pigs! Back feeding is a good way to kill linemen and generators! For Tesla coils, we have to run with a ballast on the 240V side to limit the current. I run with a 14.4/7.2 KV 10KVA pig with arrester.

[@zinaustro]

I handle transportation for a veg transformer oil manufacturer and this was a very helpful video for laypeople, thanks.

[@ricb1261]

loved your graphic's when you were showing how a transformer works - lol

[@Inflatableorc]

Inside every transformer, is the AllSpark.

[@justinbyers1725]

I met a guy working for a company that did Oil Testing on Transformers. He informed me they often pop the lids open on live transformers to take samples. He also said that's also when most new hires quit too LOL.

[@justinbyers1725]

@@billybob042665 Actually the day I met this gentleman he had to take the lids off because the transformers had no valve or plug. The substation was de-energized because it was DuPont's policy of no access while hot because the transformers were pole top units set on concrete pads on the ground. Which means the conductors were at chest level. So yeah I can't actually say he's done it live before but on that particular day the cans did have no valves or plugs

[@icevariable9600]

This was greatly needed. Good job. If possible, I’d like to see a video on the different coils and where the neutral goes in different types of transformers.

[@mrgoodwrench39]

Hi. My dad worked for the power company a long time ago. He worked there for like 30 years as a field engineer. I wanted to become a lineman sooo bad but they would not hire family. Politics. Anyway I wish I was. I have a strong knowledge of electricity and wish I could have done it so its interesting to follow you.

[@antonioking7937]

I’m curious what happens to the transformers when it gets 90 degrees and up outside

[@kaizenexcellens]

That was great. Thanks Bob!!! Interesting re the oil checks and the use of vegetable oil in some coastal areas.

[@TandD1w]

I'm not an electrical engineer, but let me try to walk through the math A homeowner generator putting out 10,000 watts at 220v is 45 amps. Let's say the homeowner's transformer has a 17k input voltage so there would be .58 amps of output current if the transformer was back fed. I'd doubt those few amps would cause the arcing shown at the beginning of the video or set a vehicle on fire. What I suspect would happen is the generator would instead attempt to feed the immediate neighbors' transformers and their homes (unless there is a better path to ground nearby). The homes probably are not disconnected so now the generator is dramatically overloaded and will blow its primary breaker. Even if the generator didn't have a breaker there is a good chance it would stall the engine from the massive overload. I'm not saying the risk isn't real I just don't know if it's as dramatic as made out to be. Why am I wrong?

[@cllewis1]

5:54 is just a GFCI mounted on the end of a power lead for a hairdryer, isn't it? Not an actual transformer, because hairdryers run on 120VAC don't they?

[@Kammfrank82]

yes i seen that too

[@TomStorey96]

Many of the so called transformers for modern electronics are actually switch mode power supplies. They do still contain transformers, but very small due to the high frequencies used in such power supplies, unlike the "wall warts" of old.

[@TheChipmunk2008]

Well it does have a current transformer inside :)

[@xenonram]

@@TomStorey96 he wasn't talking about any of the smps. He was talking about the GFCI at the end of the hairdryer cord. It's not a transformer, it's just a GFCI. 110V in and 110V out.

[@johngoard8272]

I knew the basics of transformers but this gave me a good idea of how simple high voltage one works and the maintenance of it.

[@morgan63b]

Awesome explanation. Thank you.

[@HansCSchellenberg]

I always thought the primary of a single phase transformer was connected from line to line? Where is the return on the primary side of the transformer connected?

[@onit996]

Those things to charge your laptop are not just transformers, they are a type of converter. They include a transformer for galvanic isolation. There is also a bunch of power electronics in there. With a transformer, you can only go from ac to ac, but with this converter, you first rectify the ac, then use semiconductor switches to generate high frequency ac, which can be transformed with a much smaller transformer, and is finally again rectified to generate a dc voltage of between 5V and 48V.

[@TheKurtsPlaceChannel]

Great video. Thanks for posting this. Have a nice day.

[@Bobsdecline]

Thanks "Kurt's place" you as well!

[@kevinmartin7760]

Wall warts of yore were pretty much just a transformer. Nowadays, although they contain small transformers, most of the interior parts are other electronics to regulate the output and to run the transformer at a higher frequency than 60Hz so a smaller transformer can be used.

[@bjtaudio]

The heart of a ac power transmission and distribution system is the transformer. This device makes the transmission and distribution of large amounts of power over large distances possible.

[@GH-oi2jf]

The interesting part of the transformer was covered up. I thought we would see the coils and core.

[@littlejason99]

There's a "How It's Made" episode on youtube where they make these transformers if you want to see all the internal components and assembly.

[@ChrisSmith-rm6xl]

here is a video that show that: kzbin.info/www/bejne/nWioZ6qAbM1mZsU

[@jovetj]

@@littlejason99 kzbin.info/www/bejne/nWioZ6qAbM1mZsU

[@fernandodominguez4522]

Always wondered what is inside and how they are applicable. Thank you

[@XionAzura1]

I’m an inside wireman, but I watched this for the theory and really enjoyed it.

[@swamihuman9395]

Great. Thx for the "in"sight ;)

[@Dinco422]

this is what I expect a canadian to be... cheers from romania

[@prometheus575]

I've worked with transformers all my life. They clearly have Energon cubes in them 🤪🤪🤪

[@djratino]

My transformer is 4.7K. I'm near the end of line, so my transformer uses the secondary neutral as its ground. Also it feeds 7 houses. It needs upgrading. Originally everyone had 60 amp mains. With the HVACs now, there's too much load. A neighbor running a washing machine will make the lights pulse. It's been reported to Appalachian Power, but they won't change it. 🐀🐾

[@lendavidhart9710]

Very informative and interesting, thank you for posting and sharing.

[@danielgladstone1789]

Does the current on the high voltage side return to the substation transformer through the earth via that connection from the other end of the high voltage coil to the ground?

[@tomi1744]

The power supplies used on laptops and other electronic household and entertainment equipment are not transformers at all any more. They are linear or switching power supplies which are basically electronic circuits that take care of the step down and voltage regulation.

[@deineroehre]

And still there is a transformer inside - just at a higher frequency.

[@stargazer7644]

Whose core voltage reducing component is still a transformer.

[@brianzane5748]

A few years ago, I was minding my own business at home when I heard a loud boom. I looked out the window to see a blazing inferno. The transformer on my property (bout 20 ft from my house) blew up violently. The flaming oil caught a portion of my lawn on fire, which they later dug up and hauled away. It was a perfectly calm summer night. Must have been a ticking time bomb.

[@godblesshomelessvets8832]

When I worked for a defense contractor it was my job to git the transformer and install cameras with ptz and audio! Don't always assume that what you see is what it is in a transformer 😉

[@godblesshomelessvets8832]

Gut*

[@REWYRED]

Can identify the system voltage and size in kva by the information on them. in this case these appear to be 15 kVA units with a primary voltage of 7200V. Ones around my place are marked 75 2.4/8.0, 75 KVA units with a selector switch that allows them to be used on or old 2400/4160V circuits or the newer 8000/13860V circuits the city is being upgraded to.

[@simonpaine2347]

Primitive was an understatement! I'm so surprised that A they haven't updated the design, but B that they haven't been able to add in something that stops the potential for backfeeding from the transformers. That way any feed in from generators or solar would be limited to the local area supplied by that one generator. Does that even make sense? Is it possible?

[@amiznu]

Thank you! I'm an aspiring electrician, but have only work residential and commercial projects. This fills in some major gaps in knowledge for me. I would love to see a video where you break down the delta and wye configurations and show how they are made using real transformers. It's something else I understand the theory for, but I don't quite get how it is performed on the line transformers. Thanks so much, great video!

[@airpeguiV2]

While oil also acts as a heat transfer mechanism, its main function is as INSULATOR. There is paper, which also acts as insulator, but the mineral oil is what makes it work, as paper would degrade too quickly and alone not be sufficient.

[@jesusisalive3227]

For some reason we lose at least one transformer a year in my town of 3000 people and 9 out of 10 times it's one of 3 that are right outside my house. It was really loud the last time it happened a couple months ago. We are usually the ones that end up letting them know which one went. We also seem to loose our main transformer every couple years, talk about loud and bright.

[@skabbymuff111]

Very informative, thank you.

[@shannonmoore1990]

I built these for a few years. We wrapped ours in copper, they last longer. The ones wrapped in aluminum ( like in this video) couldn’t take the heat and burned up quicker. Aluminum ones were cheaper, you get what you pay for.

[@timjohnson1199]

I work at a place that a lot of large containments with thousands of gallons of insulating oil in them like big transformer/ rectifier sets and modulators. We use a lot of canola oil now. Smells weird when it gets hot or we toast some of the components.

[@averagejoeprojects2885]

Great video, however most of the household transformers you listed were incorrect. Modern electronics use switch mode power supplys. While they do in some cases have a small transformer in them most do not and use other means to set the voltage down. Switch mode power supplys are more efficient, cheaper, more versatile and smaller than transformers. The hair dryer plug was a gfci plug and not a transformer.

[@stargazer7644]

This was a tad bit pedantic.

[@Kalvinjj]

@@stargazer7644 While pedantic, it is correct, other than (to add another layer of pedantic) saying most don't use a transformer in them, which they do albeit it's pretty much always a way higher frequency transformer, often working on square waves also. Adding knowledge in a constructive way is always welcome in my opinion.

[@stargazer7644]

@@Kalvinjj Ok, if we're going full pedant, I'd like to point out that switch mode supplies are noisier, more complicated, less reliable, more exciting when they fail, harder to troubleshoot and cost more to design.

[@intercity125]

Switch-mode PSU designs definitely use a transformer... the far higher switching frequency being used to allow for lesser eddy current losses & therefore a far smaller one...

[@stargazer7644]

@@intercity125 Technically they all use an inductor. Buck/boost PSUs often don't have a transformer.

[@sethdeppen8439]

Older ones contain pcb oil which is harmful in the sense that long term exposure will cause cancer which is why they have been replacing those with newer ones in the event of a spill, it wont be as hazardous to the environment.

[@poly_hexamethyl]

Wow, awesome! I've always wondered what is inside those. 5:30 I didn't know they were filled with liquid.

[@robertpayne1769]

Oil

[@ami2evil]

@@robertpayne1769 Oil is a liquid...

[@rogersmith7396]

I used to work with a 1950s tube type X ray defraction machine at the university. The back had about a 100 gallon tank of I assume PCB oil with breadbox sized insulators glowing white hot. It had a 10 digit display on the front of counter tubes which were fascinating. It was like Lost in Space. I never felt safe around that thing.

[@newdawn8477]

Oil and water can mix, ask any mechanic what a milky colour means on the dip stick or radiator cap. In saying that transformer oil and motor oil are both oil but aren't interchangeable. Motor oil has additives that inhibit wear and corrosion, along with detergents. These additives may make the oil conductive. And I maybe wrong but most engine oils do contain a small amount of H2O from the atmosphere and possibly from some of the compounds they add. Oil will draw moisture into itself, which your engine boils off while it runs. For small projects unscented baby oil can be used in place of transformer oil. And not all transformer oils are safe, an older type known as PCB (Polychlorinated biphenyl), real nasty stuff, gives you cancer. And not so long ago, the transformer that supplies my street went bad, boiled the oil and blew the plug out which bent the 2 end covers which allowed them swing open on the padlocked end as the pins pulled out of the hinge blocks, the door on one side slammed into the fence it was near and broke 2 of the 6" wide fence palings. It woke me up and as I dressed myself the power then went out so my guess is the primary shorted out and heated the oil up until BANG and tripped the breaker. Within 6 hours we had a nice, new transformer.

[@CITYNEWSSUPPORT]

I filmed a Transfer Fire about a year ago in the Summer here in California. The Fire Department let it burn for 45 min while PG&E Was Called Out to cut the Power ! One thing I noted was the lid and ring where on the street during the incident. Can a Transformer build pressure?

[@Bobsdecline]

It absolutely can! There is a pressure relief valve on most units nowadays, but it's definitely possible for them to blow up alll the same. Most times when we get "transformer blew up" calls, it's just the fuse that blew. When they do actually blow up, it can be very dangerous!

[@SomeTechGuy666]

What does BIL (95KV) stand for on the tag at @1:32 ? Cool video! Do you ever work in 3 phase feeds to commercial customers ?

[@stargazer7644]

electrical-engineering-portal.com/definition-basic-insulation-level-bil

[@herrprepper2070]

I recently purchased an Interociter from Electronic Service, Unit 16. It eliminates the need for transformers.

[@ddavidmac6009]

Hollinger mine in Timmins ontario back in 62 us kids would go under the fence separating the town of Schumacher from the mine property that had hundreds of those transformers stored over an area of 2 acres, we pussed over a large one and ran away. What came out was a black liquid lots of it. Just wondering what that fluid was and do they still use that type of Unit.

[@samchapple6363]

Again, very cool info ❤

[@MrChrisRP]

I know you said you don't or can't use water in this application, but think if you made the cases clear acrylic and then put goldfish in there too. Win-win I say. -Deep thoughts by CP. hahah :) Nice videos dude.

[@bjtaudio]

The power adapters around the house are not actually dry transformers these days they are mostly switch mode power supplies, they do have a small ferrite transformer inside thou but, they do not run directly at line frequency like distribution transformers do. They are not called dry transformers as such they are referred to as switch mode power supplies. In the 80's most power adapters were actually little EI dry single phase transformers, they were rather heavy. A switch mode power supply or SMPS is vastly more complex than a dry transformer, and tend to go pop more often so you have to keep replacing them for new, too boost manufacture profits. While the iron core transformer is simple, its the most clever and most efficient machine ever made.

[@jovetj]

@Bobsdecline - Lineman blogger And the one at 5:53 is just a GFCI!

[@rodrigoairesmatiassebastia1294]

love the video, just a note, the transformers that charges stuff like laptops they step down the voltage and them convert the AC to DC.

[@Bobsdecline]

Your absolutely right! I totally forgot to mention that in the video 🤦‍♂️. My bad! I've been reminded lots tho 😬. Cheers 🍻!

[@stargazer7644]

The one that drives your laptop actually first converts the line ac to high voltage dc, then back to ac at a much higher frequency (hundreds of thousands to millions of hertz) and variable duty cycle (to regulate the output voltage), then through a transformer, then back to low voltage dc. This is called a switch mode power supply, or a switching supply.

[@ryanb1874]

@@stargazer7644 why does it have to be million s of hertz, so it's pulsed dc and note asynchronous dc right?

[@dougankrum3328]

Most of the cheaper units are just a 120-12 volt transformer with a full-wave bridge and maybe a filter cap....and maybe a 12.7 volt 5 watt Zener...

[@stargazer7644]

@@ryanb1874 They use very high frequency so that the transformer can be small and efficient. Transformers for use at 50/60Hz are very large and heavy. Yes, the input to the transformer is pulsed - transformers only work with changing signals. I don't know what you mean by asynchronous dc.

[@orektez]

had no idea there was oil in them, makes me wonder about some of the extremely rusted transformers i've seen out in the countryside, those are probably going to leak at somepoint.

[@Bobsdecline]

They very well could! Dead grass at the butt of the pole is a good sign of a slow leak. The transformer will soon fail if too much oil is lost, but any unit that's showing extreme signs of age/rust should be looked at.

[@andycremeans]

Thank for this. I’m dealing with an electric box on my property and trying to learn as much as possible about electric

[@jovetj]

If you don't have a firm grasp of it, leave it to a pro.

[@andycremeans]

@@jovetj leaving it to a pro, that’s not an option I have to use but thanks for the suggestion.

[@jhonwask]

I never knew transformer oil was regularly tested.

[@davidd1395]

John Wascavage transformers except for substation power transformers are not regularly tested. Voltage regulators are regularly tested as are oil circuit reclosers (OCRs)

[@Goldwing1500rider]

Learned something tonight!! Interesting!!

[@Toggymok]

wow - thanks for sharing. Always wondered. Subscribed !

[@tihzho]

"Leakage reactance" which is a magnetic flux path between the primary and secondary windings in the form as a magnetic shunt. Normally a transformer core is rectangular with one side wound with the primary windings and the other side wound with the secondary windings. If the secondary is shorted it will draw infinite current from the primary which is impossible so it heats up then fails. With an additional flux path in-between the primary and secondary with an air gap. As the secondary current increases more magnetic flux is diverted from the secondary core through this additional flux path which acts as a ballast limiting the secondary current - a safety "valve" in other words. So producing sustained electrical arcs are possible. Old school magnetic core neon transformers are like this, the secondary can be shorted without damage. The transformer is now drawing maximum primary current which is not normal as usually they're loaded to 80% short circuit current. For example a typical 15,000V neon transformer has a 30mA maximum secondary current with a maximum load current of 24mA. Neon tubing has negative differential resistance so when current passes through the neon tube this causes a drop in voltage across it. Therefore if there is no "safety valve" the neon tubing is a short circuit to the secondary and either the transformer or the neon with fail...spectacularly. :P

[@Bob.W.]

That oil used to be full of PCB's. I assume they have changed that. We used to be up to our armpits rebuilding them.