How we change voltage on a transformer
Hey Everyone!
Last time I was here, voltage was slightly above 126/252 volts... I mentioned it can fluctuate throughout the day: An example would be, as load increases at breakfast time (hot showers, meals, getting ready for work etc...) the auto tap changer will increase voltage at the sub to compensate. Once that load cools off, it may take a few minutes for voltage to settle back down. This incident was mid morning, when voltage typically has less fluctuation. Readings of 124 volts are extremely common and had the option not been available to adjust the tap setting, we likely would have left things as is.
** These video's are NOT intended for training or D.I.Y. Only properly trained and authorized personal are allowed to work on this equipment. Always adhere to work methods and procedures particular to the company you are working for. **
Be safe Everyone. Cheers! 🥂
Don't forget to drop a 👊 along with where you're watching
➡ / bobsdecline
#Bobsdecline, #Beingalineman, #Lineman
Hey Everyone! What we're doing here is actually changing the ratio of the windings between the primary and secondary side of the transformer. Readings of 124 volts are extremely common and had the option not been available to adjust the tap setting, we likely would have left things as is. Cheers all! Weekend is almost here 😁🍻🏖️
As LED lighting upgrades surge, we are seeing more overvoltage conditions. Worst I've seen is 130/260 open circuit. That's too hot for any electronics.
What would happen if you had b A back feed from a generator and tried to change that setting?
What’s the range or percentage of deviation your allowed to go?
very interesting how those transformers work. Thanks for the video!
I'm a bit confused. There is only 1 phase going into the transformer from the high voltage line. How does 2 phase come out of it? We have 3 phase transformers here: 3 phase going in, 3 phase coming out. Also, how are the phases split, resulting in 124/240? We have 125/220 here. The US has 110/208.
I see a number of comments indicating that they would want the voltage to be on the high side, and that there is no real reason to worry about a couple of volts. For the vast majority of cases that is correct. But there is one case where having the transformer on the high side (250+) would be an issue. That would be for a residential grid tie solar installation. Instead of voltage DROP under load, you actually get voltage RISE since you are feeding electricity to the grid. Some grid-tie inverters will shut down when they reach 264 volts. Depending on the installation, a 5% voltage rise from the inverter to the transformer might not be unheard of.
First comment of this nature! Excellent information. We are just recently getting into bidirectional meters... Definitely something to consider
@@Bobsdecline I was thinking this too - that this may be why the customer noticed a rise recently, from BTM PV installs raising the overall voltage during the day. I have a rather large system (64 panels) and I don't see it go up more than a volt or two at the peak but I'd imagine if there were a lot in an area it could impact it.
Yes this is a growing issue now. Here many people are installing solar and the grid company are upgrading low voltage lines and changing to bigger transformers in order to keep the voltage down. They put the transformer taps so voltage during the night is 235V. In daytime it rises to 244V
@@Bobsdecline the biggest problem I’ve found is undersized cable from the inverters to the grid tie. The voltage drop on those cables causes the inverters to boost voltage to unacceptable levels until they trip off Locally there will be a high voltage from solar installs, but if the solar is disconnected the utility voltage is fine
Very interesting. I live in a small town that also acts as our power company and the voltage coming in at the panel is 124.6 and 123.7 volts respectively. Anyway eventually plan to add solar power to the house using micro inverters, specifically the Enphase IQ8A, should I be looking to see if they can make an adjustment or should I be fine? Right now it's about the hottest measurement I have seen overall but with everyone running AC's I figure they have things pushing a little harder.
Former transformer designer here; just to nitpick a tiny bit - there are 3 types of tap changers: OLTC - On load tap changer (Also called LTC): Can change taps on load NLTC - No load tap changer: Can only change taps while there is no load but still energized DETC - Deenergized tap changer: Must be dead before changing load
Not nitpicking at all! Appreciate the correction 👊
@@Bobsdecline I'm guessing if you try to change it while under load or while energized if its not designed to, bad things happen? BUZZZZZZZ
openning the connection to the primary coil creates an arc, an arc with 7200 volts behind it. The alternative is to make before break, but then you have a shorted turn with huge current flow.
@@liam3284 As I mentioned in my comment, the tap changers come in three varieties, with the DETC and LTC being the most common. With a DETC, the primary problem is the shorted turns when the tap changes is moving from one tap to another. The currents will be VERY high and will destroy the transformer quickly. In a LTC, there are two sets of contacts. The contacts are break before make, and they're offset 1/2 way between each other. The two contacts are then connected through a "preventer coil" that functions as both an inductor and auto-transformer. When the tap changes, the preventer coil acts as an inductor allowing all the current to flow through the contact still on a tap to prevent breaking the current. When the tap changer is in a 'half tap" position where one contact is on one step and the other is on a higher or lower set, the preventer coil acts as an auto-transformer, averaging the two tap voltages.
@@ntsecrets BOOM not buzz.... The problem is that the tap changer is creating a short on a few turns when it is between taps. The ratio from primary to those turns will be in the thousands, so thousands of amps will flow but only a few amps will flow from the primary. That wont blow the incoming protection. For distribution transformers, fusing is already a problematic proposition. To prevent blowing on inrush, the fuse has to be sized WAY over nominal rating. That means in a failure, there is a ton of energy and it can blow up. For big substation units, the problem is the sheer amount of energy available even if the protection is good. During safety training years ago, we covered a case in England where a station auxiliary transformer was re-tapped live. This transformer sat on the MV bus between the generator and the unit step up transformer stepping down to a lower MV to feed plant auxiliaries. The source was a transformer rated hundreds of MVA connected to England's 400kV system. It blew up violently and little was left of the individuals involved.
When hurricane Wilma struck Florida there were at least 10 lines poles down at a particular road by rim canal. Linemen as far as Canada came to the rescue. I was at a Marathon gas station in South Bay buying some snacks and dreams. There was also a Canadian man in full gear and looked tired. I thanked him for his labor and showed appreciation. You should have seen how his spirit was uplifted at that moment. He was very grateful for what I said. We should never take anything for granted specially when first responders and volunteers come to help those comunities in need.
I'm 75. As a new radio amateur in 1965, our family's power was all over. Hundreds of feet from street into the house, and the well pump would suck the B&W TV picture in. You had better be ready to jump up and grab the vert or horz hold adjustments on the big Zenith console behind the little door under the tube, or face the wrath of Dad At some point the neighbor, who was a widow, gave me a few things of her husband, and one was a Sola constant voltage regulator, large enough to handle my amateur receiver. That changed everything. In order, the terrible Hallicrafters S-38, Heathkit AR-3, a couple of ARC-5 surplus receivers, and an RME 4350A which I still have. Novice tx was homebrew, 6AG7 / 1625, power supply built from TV set transformers.
Love this comment. My Dad's a couple years younger. Never got real into radio but had a shortwave receiver at least. Taught himself enough to be the neighborhood TV repair kid though in his tiny rural town. Still have his Sears '65 silvertone guitar & amp which I recorded an album with myself years ago.
Much respect for you guys/gals putting your life on the 'line' for us each and every day. Nerves of steel working with that invisible killer!
I find watching videos like this to be comforting, it makes it easier for me to imagine people out there working hard at getting things working when the power or internet goes down when you see how its done a few times Also that scene up there at the transformer is picturesque, bright blue skies with puffy white clouds and grass and trees as far as the eye can see. The colors are so nice
Appreciate you taking time to write this! Cheers! 👊👊
I feel like recording these videos provides and extra opportunity to be very deliberate with both steps and safety. It’s a chance to talk through each step to the audience (and yourself) and be extra thorough. These videos are awesome! Thanks!
All I could think of when I watched you change the tap was how many times I would have had to descend to pick up the tap cap! I'd have trouble even without those bulky gloves -- Butterfingers! Kudos on your professionalism -- and dexterity.
Old mate is full of wisdom and makes sure everything he does is explained clearly. Love these videos. Also kudos for the safety wisdom in moving yourself further away when re-energizing. Many people in a rush would just slam the switch shut and hope they don't get a new suntan or a face full of oil.
I would not plug a tub in straight away from the transformer as shown, the most often place the hot oil leaves the transformer is at the junction of the lid and transformer tank. It can come out in a volcano style instantly. Better chance if you can use an extend glass stick on the ground and out and away from the actual transformer, then put the fuse closed.
I once installed some radio equipment on the roof of a 15 storey residential block in the UK. The equipment was all monitored remotely and within a couple of days, I started receiving alerts from the UPS saying it was compensating for high voltage, the logs showed it rising to about 260V at times. I continued to monitor over the following couple of weeks until one day I found a reading of 282V, at which point I rang the electricity company! They were rather concerned as the transformer supplied not only the 150 flats, but several streets too and said they’d meet me there in an hour. I arrived within about half an hour to find them already there waiting for me. Unfortunately, at the time, the voltage was just within limits, and after confirming that the voltage at the transformer was similar to that at our equipment and that the reading from the UPS was reasonably accurate, they said that normally in such cases they’d install a data logger for a couple of weeks, but in this case they’d probably be able to accept my UPS logs. The following day, they rang me to say they’d meet me on-site and change taps. In the event, there was only one more downward tap available and it still sits at about 250V, but I’ve never received another high voltage alarm in the seven years since. Overall I was quite impressed with the speedy response and not what I was expecting at all.
Wow... 250 is still pretty high, though. Glad it didn't creep up again afterward.
Maybe it was people turning a lot of Big stuff off ?
I remember years ago, during the summer, I noticed the house I was in at the time had voltage problems with lots of dimming and “dip downs”. I went outside and found the transformer I was on (an old rusty 37 1/2 KVA) and chased down the wiring and found 7 houses fed from it. I called the electric company and told them I felt it must be overloaded. They came out, and agreed. They replaced it with a new 50 KVA and the problem went away.
1/2kva? You mean 500va? And 7 homes from it? A couple og light bulbs would overload that thing
@@KuntalGhosh 37
@@KuntalGhosh 37-1/2 or 37.5
As a residential electrician, the issue I’ve ran across in the past (many times) is seeing perfect voltage across both legs in a house UNTIL a load is put on that neutral. Plus or minus 3-5 volts is never an issue. The load tester some of y’all carry seems to show the high/low voltages pretty quickly though. I don’t mess with powerlines… that shit will get ya kilt!!! Lots of respect for the lineman on here 😎 I don’t get how y’all play with powerlines in the rain, snow, night or day… Y’all are def committed to getting the job done ✅ and it is very much appreciated. Stay safe ⚡️
Just came across your comment and thought I'd share an anecdote on voltage spikes with high neutral loads: In my old house, when we moved in, I checked all the voltages and everything seemed up to spec. But after actually moving in, I started seeing evidence of small surges as my lights would get brighter or dimmer when say, the portable AC would kick on, or any other significant 120 load. Took me forever to realize it wasn't happening with heavy 240 loads. Turns out, the neutral line back to the pole had somehow become severely degraded, and when I put a clamp meter around it past the main box, almost no current was flowing at all. That led me to learn that, either fortunately or unfortunately, my ground connection was doing its job and capable of carrying all of my neutral amperage back to the pole, although not without some resistance along the way. It's kinda creepy to put a clamp meter around your water line and see a double digit number. So yeah, the system was almost working as intended except that there was some (although not a lot) of resistance effectively on the neutral's path back, resulting in the neutral having a non-0 voltage when loads were high, and de-balancing the apparent voltage on the two legs.
Shit I just did a service in a snowstorm lol same thing
Great info. Never knew of the adjustment on some of these transformers. Love your channel - watching you work and learning.
I'm currently attending lineman school out in CA and we were talking about substations and LTCs in class. Really cool to see one up close in the video. Thanks for sharing.
I love that you always promote safety, and why it's important.
Had a voltage of 142/284 once. Fried a power strip/surge protector and light bulbs were blowing prematurely. Power company came right out and fixed it.
Ouch! I've seen one leg go high like that with a bad neutral connection, but I've never seen both sides go through the roof like that... (and here's hoping I don't see it anyttime soon...)
@@bradwilmot5066 Also lost a neutral in the same location. Voltage swinging wildly throughout the system. No major electrical draws in that house. Stove, furnace, and water heater were gas. Had central air. Only thing that gave it away was lights dazzlingly bright in some areas, dim in others. Thankfully no electronics were damaged. The service was well grounded. Some of the neutral current was making its way back to the transformer through the ground. Tree branch had fallen on the secondary lines and yanked the neutral loose at the pole.
Like Brad mentioned, 142 is common on one side with a broken neutral. I've seen it on both legs a few times though 😟. Tx winding failing can mess with the ratio can do that, but usually the fuse pops pretty quick. The other scenario was a result of some severe vandalism that resulted in a tap changer going full boost
@@Bobsdecline Bob, down here in Central Florida, I see high voltage on transformers that have been hit by lightning. We’re the lightning capital of USA and you may not experience that much lightning in Canada.
Really appreciate your videos, especially the one to install a much more optimistic electric meter on the house, saved a fortune in the last few months.
I just prayed for you Bob and the thousands and thousands of HV linemen all around the world. God bless and keep you in His loving arms!
Thanks for your videos! You open windows for us to peek in and see exactly WHY our lights come on, the tv works, and we have all the other electrical things we depend on! Stay safe! Bob
Extremely informative. First time seeing this information. Beautiful maintain lawn in the video.
Man, that’s a dangerous job. You got high voltage and height . Thanks for the video 👍🏻
Nice thing is if you become a ground source for 7200 volts, you don't have to worry about falling, you'll be long dead before gravity gets you. So really only one thing to worry about.
I didn’t know they had those. A few years ago after a brief outage my line to G voltage dropped to 100v! I called and called and after 2 days they sent out a guy who measured it at the meter, got in his truck in a hurry and drove off somewhere, came back 10 min later very apologetic saying it affected the whole area and a regulator was out of whack.
Definitely an occurrence we want to find quickly. It's not overly common but does happen. We're always that thankful for keen customer phone calls on that one when monitoring equipment doesn't catch it
With the rise of smart meters, they should already know. (i.e. confirm when you call them.)
@@jfbeam my meter only transmits locally to a van they drive around once a month to collect the data. So they wouldn't have been able to tell at least from mine in real time.
@@ntsecrets ... meters don't transmit voltage. They are strictly for reading the Kw used.
@@rupe53 You're right - been a while since I decoded it using rtl-sdr - the packets only include consumption and tamper info. Sorry about that.
Thanks for the tip on the glove storage! I did not know some pole pigs had an external adjustment on them. Neato!
Thank you for another informative video. I keep learning something new each time. Have a great weekend!
You guys definitely do not get paid enough . But much respect and many thanks for keeping our power flowing to the air conditioner
Spend awhile paying California power rates and you will realize someone at the utility is getting compensated decently
Respect. Love seeing the work through the lineman’s eyes
I actually didn’t know cans had a tap changer, only ever seen them on the sub transformer. Great video!
Hey Aaron, just wanted to say I appreciate your videos. They are very informative and I can tell you take pride in your work. I hope I get to work with someone knowledgeable like you in the future. Graduating line school in a few weeks! Keep the videos coming, I’m learning a lot! Cheers👊🍻
Nice! Congrats on your achievements so far 👊👊! I appreciate you taking the time to comment and share. Cheers!🍻
What school did you go with?
Been watching your channel for awhile. Very cool stuff. I am a residential electrician in New Jersey. I always thought pole transformers only had switches for the primary voltage to use it on different systems. I don't think we have tap adjustments here. The last low voltage complaint I had for a customer ended up with her getting her own transformer which solved the issue. We also have tons of voltage regulators so I think my local power company tries to deal with voltage issues that way.
I had no idea how any of this infrastructure worked. Thanks for educating the world.
Stay safe always , thank you !
My mind is absolutely blown to find out that you can actually change the voltage on a transformer
Happy to see you doing well . Hope the winter has not been too bad on you .Stay safe. Garfield Brown Scottsboro Alabama USA .
Great Vid!! 😎Stay safe out there Aaron.
i know nothing about this i am a mechanic but i very much enjoyed this video! aint no joke what yall do, stay safe!
That was cool to watch, never seen anyone do this kind of work.
This may be my new favorite channel for the week! Or two!
Nice options on those transformers. Talk about a nice easy call 👍
Best video yet homie. Keep up the good work sir.
I would think all transformers would be able to adjust like that one but it probably costs more to build them like that very interesting buddy god bless all linemen my power was out after the last storm and luckily it was restored after 8 hours but several people was out 2 days I could have hugs those guys that day it was hot and I can’t handle heat with my health thanks for sharing buddy
Thanks Scrotie! Glad to hear your power was restored fairly quick. Always great to hear from ya!
That’s super neat. I didn’t know some transformers could change taps like that, but it makes sense that you’re just changing the winding ratio. Fist bump from Shreveport and I love your videos, bro!
Thanks Bacon! Mmm... Bacon 🤤
Learned something new tonight. I never noticed that adjustment on any transformers I've observed. It might be there, but I thought the wires were the only thing worth looking at. Can't wait till morning so I can have a closer look.
Balls of steel doing that job great work hats off
Kudos man...I seen what you guys go through and it's extremely dangerous work!! Stay very safe!! And thank you for sharing....
Always enjoy your videos. Well done
Great video! A fascinating insight into the world of linesman electrician in the USA - here in the UK things are quite different!
Canadian accent.
Wouldn't be on a boom lift under a live line that's for sure 👌
Learned so much from your channel . I used to shoot the fuse with A .22-250. Then do the hot tap . Now I use a shotgun and pull the fuse tks bro
Great video
Thanks, I've always wanted to be able to fix my own grid feed.
Respect and thanks to all you brave crazy people who do this type of work, one mistake and it's over in this line of work around high voltage.
Thanks Aaron. That transformer seemed to be a rare example with the tap changer. I've done that many times on 480 Volt three phase pad transformers adjusting the taps to match the primary to lower or raise the secondary.
Definitely way more common on padmounts!
@@Bobsdecline Any chance that adjustable transformer was put there because it's so close to the substation and this issue was foreseen as a possibility?
I'm shocked your company would authorize this work when it's within spec. This would never happen where I live. Good work.
Only because there was a simple solution.... If the tx didn't have a tap changer, we wouldn't swap it out where the readings were good.
The difference between performing a check and doing the change was all of 2 minutes, the equipment was there to make the switch a simple process.
Outstanding!! Loved every second!!
This was very very interesting! Thanks so much for sharing this with me!
Great video! Thanks for posting!
Nice to hear from you, everyone is fine. There is a lot of work at the moment, two weeks until vacation. Hope you are fine too, great video. bump
Oh nice! Same here... 2 weeks, for two weeks. Glad to hear all is well! Summer is usually our busiest time, so vacation is restricted a bit during summer months. Basically 2 weeks per guy with a seniority based draw.
Thank you Aaron! Very informative video. Stay safe my friend. 👊👊
Thank Alan! Hope all is well 👊👊
You have a nice view & perfect blue sky ... the stuff an office worker not has ...
Very interresting and educative!
Very interesting... Thanks for posting
not many pole transformers hear in eastern US have tap changers. running slightly high can be a good thing. with hot summer load of AC you don't want to drop much under 120V/240V motors will draw more amps and run hotter. all newer appliance can handle 5% change of line voltage or more. If a customer has old electronics ,that can be fixed buy auto transformer with taps or AVR unit or even a bucking transformer. like old tube radios from 1930's 110V some 115/117V . from Boston NY,USA most around 242/245 hear .
Great info, thanks for the comment Robert!
One of the good things about vacuum tube electronics is they will run just fine on much lower than normal line voltages, so you can get away with using something as simple as a dim bulb (a high wattage lightbulb) in series with it.
Who ever created that fuse design is a mad genius IMO. Uncle was an engineer for RTE
Cool. Thanks for sharing!
Good job man! Hope young people continue to choose this career or we are screwed.
very professional and aware. very impressed! thanks
Amazing what you guys do as linemen and what safety precautions you take. Keep up the great work and thanks for the video. Take care and be Safe.
Great video man. Would love to see some more videos on tips and tricks using the long stick
Fascinating...thanks
You could not pay me enough money to go up there. It is fascinating to watch you do what you do.
Your awesome! Thanks for sharing this.
Great Video Blessings From Costa Rica CentroAmerica from a Rural Electrification Cooperative
nice satisfying 120Hz buzz from the transformer core when you closed it back in 🤣
Thanks. Good to learn something new.
Hey that was cool! Thanks!
Had high and low voltage conditions all in same day. Pretty regularly. Turns out the hard drawn copper secondary was the issue. Couple spans replaced with triplex, and no more huge swings.
Sounds like a bad neutral connection! Likely a connection between copper and aluminum...
@@Bobsdecline A friend of mine's dad had a broken neutral a couple months back, found it after he measured the window AC with my Kill-a-watt ... He just happened to be on the phone with me as he had our local cable internet company out to fix their internet, and he mentioned melted coax.. That coupled with the huge voltage swings(Circuit the AC was on dropped to 80V) and I told him to measure line to line and make sure it was still 240 in that scenario, then we determined the coax shield was acting as the neutral for the house. Power company had to come out replace the triplex, the neutral had abraded and rusted on a tree limb.
@@Bobsdecline the excessive sag didn't help during higher winds either 🤣
@@thewhitefalcon8539 Yeah, modern electronics have boost-mode power factor correction typically on the input stage, that allows for the large voltage range and frequency variation on the input, often 100-250V. He never told me that anything failed in the house, aside from the internet going out (for now obvious reasons). Guess they got lucky. Definitely not a great situation to have.
I really liked and learned something from this video. Ty
On a hot summer day here in Northern Alabama USA - I'm sitting at 116 volts per my Kill-A-Watt plugged into the outlet above my workbench. :) Very interesting video! Next time I'm outside I'll have to see if there's a tap changer on the transformer that feeds my house. :) Thanks!
I noticed the way you out those gloves in before you mentioned. The integrity of those gloves is paramount
Great info. Thanks
The real freakin' heroes, out there keepin' the power on.
Absolutely Appreciate The always informative explanation you give from even you first VIDJA ! ❤️🏴☠️🎥💯%👍🏻👌🇨🇦
Great video! Didn’t know pole mounted transformers had tap changers.
Good video, thanks!
Great video 👍🏻
Thanks for the Video 👊👊
Thanks Patrick! 👊👊
I am an electrician in Brazil, our tap change procedures are very different from those carried out in your country as they are simpler, here we cannot do it without first carrying out an analysis of the transformer loading so as not to have problems with voltage changes when the load increases or lower depending on consumption.
Your hard hat i hope is specific, for the voltages your working. it also looks like it doesn't fall off. We have some generic hard hats, one vented and one sealed for work in the catenary sytem area for the train. even if you are on the tracks not working on that system. Love to know what hat that is. I tried to get a klein hat but safety didn't approve it, but aproved similar for other people. Hope you enjoyed your vaction. I just stayed at a rental house and there was i think a voltage reuglator. It had three feeds from the three phases, and three outputs. And a nearby pole 20' from it which had two wires to a third pole with a transformer for the two houses next to each other across the road. Yes it had the adjustable tap. As i was traveling i also saw the constuction of a power line right of way with pulleys hanging for a new distribution line! Big towers!
Interesting. I’m in Australia I’ve got 250v at my place, it’s been like that for 20 years. We used to go through incandescent bulbs rather quickly, but now with fluorescent or LED bulbs they last for ages.
This is super helpful, I’ve been meaning to adjust mine up a little, I have a fiberglass painters stick should work for opening up the cutout?
That’s super neat!
Super interesting dude
Just noticed a couple of things you do different then our company and was just wondering if you have ever had any trouble with your company watching your videos or if they have ever given you any feed back on them. Keep up the great work and stay safe.
Just a little advice, not criticism. But it wouldn't hurt to check and make sure you're not getting backfeed. Up here in New England every now and then I come across a transformer being backfed from a generator or the secondaries have been tied to another transformer and never separated once the new transformer was installed. Again, just a little advice.🙂
Yes, I have also seen transformers hooked up in parallel, but the wiring is usually obvious. As someone who was in the generator business for over 20 years, I am aware of gen sets running in the distance, but now with solar (and battery backup) you really need to check things because there is no noise.
Kindof surprised that there's no built in light or indicator in the transformer that would be lit whenever the transformer is powered, whether by the main or backfeed
@@DRawwrrr ... in most cases there's enough stuff connected that you can glance down a street and see if there's power or not. IOW, it's not necessary. BTW, some transformers have an indicator light for temp. They will automatically shut down on overheat at some point. The light is just an early warning.
@@DRawwrrr Some older transformers did have lights. But they can't be relied upon since they can just as easily be burned out.
Never knew this. I Have issues at some sites of VFDs faulting for high mains voltage. Measured 254 when I was on site, never did any data logging. Could be as simple as a tap change on their transformers.
Mad props from a commercial electrician
Here in my part of Norway my utility company change the taps on the transformers several times during the day remotely. Or maybe automatically based on load. One transformer powers maybe 50-100 houses, so they tend to run on the high end of 230-240V to be sure that the last on the line still gets decent voltage. But looking at the data from my smart meter, that gives me voltage on all three phases, I see how the voltage drops in the morning when people start waking up and it slowly drops from maybe 235V to 230V, and then all of a sudden from one measurement to the next 5 seconds later the voltage has jumped up to 235V. And then it slowly raises during towards noon where it usually goes up to maybe 238V, and then it has a instant drop to around 232V again. And some times there is a jump in the afternoon/evening too.
I like your *disclaimer* but many don't see it, your title might be better as "How WE change voltage on a transformer" as the we refers to your industry/company and not to the DIY type. Really good content, keep them coming!
That's a really good idea ! Appreciate the feedback 🤝👊
@@Bobsdecline I came across this today " www.foxbusiness.com/lifestyle/extension-cords-sold-amazon-should-immediately-thrown-away-cpsc-says " and while they mention several 'hazards' with junk being sold they don't say anything about the tiny generator creating 7 KV or more when back-feeding your line transformers!!! Can you please make a video addressing these suicide cords, portable generators and proper 'electrician installed' transfer switches? There are many KZhead videos where red-necks are showing dangerous installs as if they were legal or safe. Some even show how to make and use a double male cord!!
My thought would have been to check for voltage across the secondary after pulling the fuse, just in case of backfeed. Then apply ground cables across the secondary. That fuse was hanging right in your face while you were touching (albeit with gloves) the grounded transformer case. A backfeed at that moment could have been... enlightening...
240v.. no big deal. cant be very much stored energy.
@@bigiron4018 But 240V transformed back to 7200V through the transformer... rather shocking.
Thank you father. I'm sure this guy would never survive if it wasn't for your supreme knowledge.
The gloves are insulated sich that he could touch the energized lines without problems, that's why he's wearing them to mitigate risk.
As an E.E. student, this is fascinating!