![Three Phase Innovations](/img/default-banner.jpg)
- Видео 11
- Просмотров 53 123
Three Phase Innovations
Добавлен 16 янв 2019
Transformer Training
Induction Training Coils
Jason Leary and Josh Nichols have taken the components and function of a transformer and put them into perspective using our induction training coils.
Просмотров: 1 234
Видео
Corner Grounded Delta Transformer Bank
Просмотров 19 тыс.4 года назад
This demonstration video shares the wiring, voltage and history of a corner grounded delta bank. We use our trainer model made by Three Phase Innovations to do the demonstration. Thank you and enjoy
The Effects of Backfeed Within a Delta Transformer Bank
Просмотров 3,8 тыс.5 лет назад
This short video shows how we can use the training simulator and visually demonstrate backfeed in a Pole Mounted Transformer and how it will affect a distributions circuit and cause dangerous hazards for a Lineman.
Why Do You Always Tie a WYE-WYE Transformer Bank
Просмотров 7 тыс.5 лет назад
A WYE-WYE bank must always be firmly tied to the system’s neutral; if not; excessive voltages may develop on the secondary side. This voltage, known sometimes as a third harmonic voltage, can exist between the primary neutral and the system neutral and ground. This excessive voltage can be hazardous to a Lineman. In this short video, we will show the effects when a neutral is floated on a WYE-W...
Phantom Voltage in a 3-Wire Delta
Просмотров 2,3 тыс.5 лет назад
This video shows how to use the Low Impedance setting on a meter and how you can effectively measure the voltage on a 3 Wire Delta Bank.
4 Wire DeltaTransformer Bank with a High or Wild Leg
Просмотров 7 тыс.5 лет назад
This video will demonstrate how the voltages change in a Delta bank when one neutral is added to the service. The effects when adding the neutral will create a voltage know as a wild or high leg. It is very important to locate the neutral and determine where your high leg is in the service. Damage will occur to equipment if the high voltage is applied to equipment not designed to handle the hig...
Induction Training Coils
Просмотров 6025 лет назад
Our latest equipment includes our Induction Training Coils. These coils will show exactly how a transformer works through mutual induction. An apprentice can hold a transformer right in their hands and see how the primary and secondary coils act upon one another. It also comes complete with an iron core and lets the apprentice build the transformer to better understand how all the components he...
Introduction to Three Phase Innovations Training Equipment
Просмотров 5245 лет назад
This video clip is just a brief overall introduction to the training simulator and how it can be used in a “hands-on” classroom environment as compared to some of the obstacles of using so many different scenarios simulated in a field setting. The troubleshooting, recreating past accidents, or just testing out new transformer hook ups and banks are just a few of the features that the model can ...
Corner Test Point for a Wye-Delta Transformer Bank
Просмотров 2,5 тыс.5 лет назад
In this short video, it is explained how you can test the polarity of a Transformer Bank before energizing the bank on a service. This important step can make sure you have the correct polarity on a 3 Transformers to avoid any damage to the equipment or personnel before energizing.
Paralleling a Wye-Delta Transformer Bank
Просмотров 4,8 тыс.5 лет назад
This video is a very brief introduction into how the model can be used to parallel 3 Phase Transformers banks. The model can be used in all types of scenarios to parallel any type of bank. This is one of the best features of the training simulator that rarely can be covered in the field due to the model being able to use real voltage setting in a classroom environment.
Three Phase Innovations
Просмотров 4 тыс.5 лет назад
Three Phase Innovations has been building and delivering quality products crafted with the highest standards of detail and craftsmanship, since we opened our facility in 2015. Our craftsmen are detail oriented and understand the importance of creating products that are designed to replicate on site conditions and equipment that will provide real time - in the field - experiences. Our equipment ...
How do you ground a hot
A three phase Delta circuit (3 wire) is a SERIES circuit (one path for current to flow). You can have one neutral in a series circuit. It is not a fault to only have one neutral. It just creates a path to ground. Putting two neutrals in a delta circuit would cause a dead short. One neutral can be used to create different voltages for a customer (center tapping one transformer can = Lighter Pot) or you can use the neutral as a corner ground. A corner ground provides safety to a delta 3 wire bank and it can prevent a customer from stealing power due to a meter only measures two legs of a delta because it once again is a series circuit. Corner grounding will also make sure a fuse might blow if one of the other phases accidentally becomes grounded but always be aware a Delta is not dead unless all 3 phases are de-energized.
@jasonleary6717 I need a video explaining this, I'm hands on so I don't fully understand in my world a hot to ground or neutral will short
My multimeter doesn't have a Lo Z setting, but I also have an Ideal Vol-Con solenoid voltage & continuity tester, which I turn to in situations where I suspect ghost voltage readings on my multimeter, or where I'm verifying the absence of voltage for LOTO procedures and don't require a precise reading. The other feature I like with solenoid voltage testers is with experience, I can have a close estimate of the voltage levels by noting how hard the solenoid pulls in and the vibrations in my hand even while wearing electric shock and arc flash PPE, which I find very helpful when wearing a 40 cal/cm² flash suit.
Sad this site doesn't have 500k subs.
@mkidd8806 Thank you for the support and feedback. These are some early videos we were experimenting with. The audio was terrible but if all goes well, I hope to have a new video or two by the end of the month. I had all kinds of request for a floating neutral video and a transformer polarity video.
@jasonleary6717 thanks for the reply. Anything dealing with transforms on the utilitie poles and inside buildings. Also bonding, grounding, neutrals. Anything concerning the use of wye and delta service etc. I will soon check out your video on corner ground delta. Am 72 and my early career there was true 2 phase and if memory is fair may Pennsylvania has a couple of areas. Good luck from Waco Tx
I need me one of these
Dumb question. A ground and a neutral are basically the same thing when adding your corner?
Thank you for the question. A Ground and a neutral have different functions in a electrical circuit but in a 4 wire corner grounded Delta, the neutral is acting as a safety or to prevent the stealing of power. (120 volts) If a 3 wire delta is corner grounded then you can't have a phase get accidental GROUNDED and no one not know there is a phase to ground potential in the circuit. Always remember, a DELTA circuit is a series circuit (one path for current to flow) a neutral can show up and know know there is a potential to ground, if you ground a 3 wire delta now you have protection from accidental grounding. Here is a great you tube channel for all thing electrical. ruclips.net/video/JBpQ9Fodz_Q/видео.htmlsi=TzDHvtDCX1sRkBXN
So when you have a circuit on the grounded phase and that circuit has a short to ground how will that circuit be grounded if it is already grounded? Im so confused.
Thank you for the question. A Delta circuit can be a 3 wire circuit with no ground or a 4 wire circuit with a corner ground or the neutral can be used to get different voltages for the customer. ONLY ONE NEUTRAL CAN BE USED IN A DELTA CIRCUIT. If the circuit is a 3 wire DELTA then no phase to ground voltage is present, because you have no neutral. The danger with this 3 wire circuit is a neutral could show up accidentally and the DELTA circuit will not show any signs of a problem other than having a phase to ground potential there and no one aware of it. If you chose to ground a 3 wire circuit, then you have a 4 wire CORNER GROUNDED DELTA. Now one phase has a ground potential in the circuit. If there is a problem or a fault in the other two phases now you will blow a fuse and know you have problem because TWO neutrals will be in your DELTA circuit causing a dead short. Just remember a Corner grounded delta is used for two purposes. (1), To prevent the stealing of power by a customer (120) volts. (2) to prevent a 3 wire delta from accidentally being grounded and creating a phase to ground voltage without the customer knowing they have a problem with accidental grounding that could cause a accident for workers working on the equipment.
Did you make the prop or purchase it? I am a planner and have been looking to make one to help explain phase and voltages to planners in training.
Where is the neutral on the three PRIMARY (wye )windings? Is there no neutral back to the SUBSTATION with this three wire distribution system? Is the THREE WIRE distribution system a delta or wye?
In this example, we have a Wye-Wye 120/208 3 Phase bank. We are lifting the neutral connection from H2 on the transformers to show what happens to the phase to ground voltage on the transformer bank. Notice there is hardly any change in voltage from phase to phase. Always take 6 readings when troubleshooting 3 phase power. The neutral in a 4 wire Wye stabilizes the connection and is a current carrying conductor. A 4 wire Wye system gives you TWO differences of potential. A Phase to ground and a phase to phase voltage. You could have a 3 wire Wye system but every phase would have to be perfectly balanced so a neutral would not be needed to carry the unbalanced load between the phases. A 3 wire Wye would not give you a phase to ground potential though. The 4th wire in a WYE makes sure the Phases has a return path to balance the circuit. The neutral will carry the unbalanced load between the phases. The neutral on the high side is coming of the H2 bushings and the ground on the model is the wire below the transformer cans. When the neutral is lifted or disconnected you lose the 120 degree displacement in the bank from phase to ground. This is why the voltages spike when checking the phase to ground connection. Always remember the ground balances a 4 wire Wye circuit and is a current carrying conductor. If disconnected, loose or just a bad connection, the neutral can have the primary voltage looking for ground and if you become the ground you will get hit by the voltage from phase to ground.
@@jasonleary6717 Yes, Kirchhoff’s voltage law for series circuits (open or lose Neutral conductor). Thank you
@@jasonleary6717 Is the Neutral coming off of the H2 bushing grounded to the can ONLY and not going in parallel on another conductor back to the substation? thank you. P.S. Meaning Mulit Point Grounding system at EACH POLE that has a transformer.
@@tedlahm5740 In this scenario it is a isolated transformer bank showing the dangers of a broken neutral at the transformer bank. Our goal is to show a open neutral coming off the H2 terminals or a bad connection. Troubleshooting with the meter shows the problem by checking voltages.
Great video. I'm an electrician and an HVAC co-worker approached me this morning with the problem of; two phases had 480 to ground and one phase 0. Never heard of this before. Very good presentation and explanation.
I see open deltas all the time in West Texas. It’s very common in the oil field. Thanks for the video.
In the USA the NEC requires, on panelboards, for the high leg to be on phase B. It must also be orange, or by other effective means. If running a 240V single phase load from this system, you could tap A-B, A-C or B-C, but with a catch. Most two pole breakers are rated 120/240V, in this case you cannot tap B because B is 208V to ground so you'd have to go A-C. There are straight 240V breakers available but these are special order and you can forget about walking into your local home depot and picking up a straight 240V two pole breaker. Typically this system is found in older commercial and industrial facilities, as well as some newer facilities in extremely specific applications. Only useful where most of your loads are 3 phase motors, with a small amount of 120V equipment. Load balancing tends to be poor when compared to a more common 120/208Y system. Also a very easy and costly mistake is to connect a single pole breaker to the B phase thinking your getting 120V, and smoke up everything on that circuit when the breaker is turned on.
Love you man… thanks for explaining
Very well explained. Corner-grounded delta has long intrigued me and have never seen one, although I've read quite a bit about it. I do think the term "grounded phase" seems like an oxymoron, maybe that's one reason it puzzles me some. I also think it's pretty cool just because it can be done.
Did you think it was going to work when you grounded it? Video should have been labeled why you can’t tie these two banks together…
Hey man, I’m trying to learn the complete process for paralleling 2 480v 3 wire delta delta closed banks. Do you know how to do that? Can you teach me if you do? This video was a little helpful but I’m still not completely certain on how to do it.
Can you corner ground a 240 delta system and have an ungrounded 120V center tap? I understand you cannot have a redundant ground, but couldn't you still have a 120VCT with a corner grounded system?
Hello, and thanks for the video. What if I need a neutral on the corner grounded delta??
Thank you for the compliment. A Delta circuit is a Series circuit (one path for current to flow). You can ONLY put ONE neutral in a delta circuit. You can use the neutral as a corner ground or use the neutral to center tap a can for different voltages but you can only do one or another at a time. You can't center tap with a neutral and corner ground at the same time. It would be to many neutrals in a delta circuit at the same time causing a short in the circuit.
@@jasonleary6717 hey thanks for the response, so i got it. so the corner ground acts as a neutral to carry the load unbalance¿? the reason i ask os because i installed a buck amd boost on that corner delta for a three phase stove, and i read in the buckboost that if the load is unbalanced it needs to be tied to a 4 wire system, but i am not sure what is the asumption. their specs are very poor, just a label.
@@celsiusfahrenheit1176 I have never used a buck-boost transformer but I'm guessing that it is a transformer that makes changes to a fixed voltage. As a lineman we have pole mounted transformer with tap changers that do the same thing by adjusting the primary coil's turns ratio to match high or low voltage on a distribution circuit. If you have a 3 wire delta bank, you would have just one voltage to chose from between any two phases; however, when you corner ground a phase you do stabilize the ungrounded phases. An example would be having a 240v 3 wire delta. There would be no phase to ground voltage except for phantom or ghost voltage which can be corrected by using a meter with a LoZ setting on it. We have a phantom or ghost voltage video on a 3 wire delta on here as well. So, lets say you corner ground B phase on a delta circuit. Now your voltages change in the circuit. B to neutral will read zero but A and C phase to neutral will read 240 volts. It stabilizes the other two phases not grounded. I'm guessing like you mentioned the neutral on that type of transformer is needed for the unbalanced load to have a completed circuit to stabilize the ungrounded phases but that is just my best guess on this situation.
@@jasonleary6717 nobody really knows, i wil talk to the engineer from the poco. i never saw a three phase stove before, i told the custumers in writting when they asked me, that their service was a 3 phase corner delta no neutral 240v they still got a 3 phase 208v no neutral required. anyways thanks for your replays.
Very nice trainer, with 4 bushing secondaries. Great video.
Why does such a good channel have only 600 sub?? This is great info!
Are the test voltages of 40(wye-delta) and 10(delta-delta) based on a specific secondary rating of the transformer? Or will it always be 40 and 10?
Mark, that is a very good question. We have used various high voltage applications as well as different kva transformer ratings. But we the secondary voltages have always been 120/240-volts this is due to the harmonic build up between the primary and secondary coils that cause these voltages. Keep in mind they can drop 10-20% based on our studies. We need to try this with a 240/480-volt secondary and see if the results are the same. Again great question Mark.
@@threephaseinnovations7546ave you ever ran across a 240/480V 4 wire delta? I've heard of them but never came across one since they are extremely uncommon. I've seen 120V/240V 4 wire open deltas in rural settings where a farmer needs some 3 phase power for motor loads, but the majority of the loads are 120/240 single phase.
Hey thanks for adding this video. Never paralleled banks before but I’m curious where this would be necessary? When powering open wire with power leg? I’ve built banks but we only really use wye delta 120/240/208 and have never had to parallel Thanks.
Hello Funk master flex. Thank you for taking the time to check out our videos. Any single phase, open bank or three phase bank can be paralleled together. The main reason is to make sure your customer is never out of power. You could also wreck one bank out and the customer would never lose power while the other bank back-feeds the customer until the new bank is installed. There are still many delta distribution systems on the power grid where all banks are tied together. Detroit, Michigan would be a good example of this. You can also tie single phase pots together. Example would be taking two 120/240 cans and hoking the coils in each can in series and then building a 480V service if needed. Each single phase can would have to be on the same phase though.
Alright cool now let's talk about fault characteristics...positive negative and zero sequence components or what's the function of a Buchholz relay. Transmitting power from point A to B is important. However There is no power without everything inside the substation doing what's necessary to make that happen.
Very helpful, thanks.
In one section of the plant I work in I'm reading 480v between all phases and A: 488v B: 402v and C: 82v to Ground. I was under the assumption it was a corner grounded delta and maybe something isn't bonded properly but I'm not positive. I know you can wind up reading a little bit of voltage on the Grounded phase but I have never seen something as high as 80v. I was hoping you could shed some light on what might be happening in the system.
Hello Bryan, Corner Grounded deltas or 3 wire delta banks can be tricky. One of the phases should be labeled or have some kind of identification to let you know what phase is grounded. If it is a corner ground, the other two phase not grounded should be stable to ground. An example would be having the B phase grounded. It should read 10 volts or less on a meter (B Phase to ground) but if you have a meter with Low "Z" setting you should get a more accurate reading. Phase A and Phase C would still read 480V to ground if it is a corner ground. If it's a 3 wire delta and have have readings like you mentioned then whole new troubleshooting problems occur. You may have a piece of equipment or a ground come into the circuit and now you have to find it. When a 3 wire Delta gets an accidental ground, volt meter reading can become very strange depending on the resistance to ground or the type of meter you are using. The Corner ground Delta bank was created to prevent some real troubleshooting problems for 3 wire delta banks and for safety. Just one ground can exist in a Delta bank and not affect the bank at all. I doubt this helped you much with your situation, but you might want to see if your plant has any old electrical prints, warning lights or maybe check out the transformer bank outside on the pole feeding into the building. Sometimes a corner ground Delta is much easier to spot on the transformer pole itself to see if a phase is grounded. good luck.
This was helpful. So it sounds more likely that we have a 3 wire delta, thus the goofy voltages. I’ll be digging into this a bit more now to verify. Thank you for your quick response and expertise.
@@jasonleary6717 hello. i like your explanation and video demonstration. i have an ungrounded 3 phase 3 wire delta going to a customer's 3ph 480v motor. he has no electrical issues to speak of but i wonder if he's aware that one of the phases is grounded at the meter. there is no identification on the grounded conductor; however, at the meter socket is a bonding jumper on the middle phase wiring lug with a manufacturer's tag that clearly states: 'When service is not grounded, remove bonding strap..." i think that's dangerous to ground a phase at the meter because what happens if the equipment (in this case the meter enclosure) ground comes loose? so where is the proper place to ground a phase if not at the meter?
@@betta3301 Thank you for taking the time to check out the video. I really can't give you a great answer to your question; however, when it comes to grounding any electrical circuit, the NEC Code book is very detailed to say the least. I suspect that Local or state codes might also have something to do how the circuit is grounded. I also suspect the circuit might be grounded only in one location so the circuit could easily be underground if need be at certain times for whatever reason. The main thing to remember when dealing with any DELTA circuit is always be aware of back-feed and ONE neutral can be in the circuit making it a 4 wire DELTA. Corner grounded or center tapped to obtain different voltages (120/240 etc..) Electricians have always said troubleshooting a DELTA, which is just a series circuit can be tricky. Section 250.1 helps you overcome a common problem that leads to misapplication of Article 250. Most folks are so overwhelmed by Article 250 that they immediately get lost when confronted with it. However, it’s divided into 6 logical groupings of information and Section 250.1 of the NEC codebook tells you what those are. Good Luck and stay safe. :)
Cool
HVAC service tech here. Came across a Corner Ground Delta configuration today. Thought it was regular 3 phase and the customer simply had a faulty breaker. Oops
Corner grounded delta's can be tricky. I'm glad I'm on the Lineman side of the bank. So much troubleshooting on the electrician's side. :)
This is impressive
Just ran into this in a waste water treatment plant. 480v delta. Reading 480v to ground on A, and B phase but on C phase i was reading ~11v. Thought I had lost a phase, called POCO, lineman came out and explained what type of system we have.... this video has a great explanation! Thank you for making videos like this so other people can learn! 💯
Hello Mr. Rodriguez. Thank You for taking the time to check it out. We really appreciate it.
i'm seeing the same thing at a similar location. if i may ask, where are you seeing the conductor being grounded?
@@betta3301 not sure I understand your question. I was reading the ~11v after the transformer
@@pumarodriguez3964 you stated you have a grounded phase conductor and i was just wondering where you see the phase being grounded at, if possible. if its inside a pad mount transformer then its not obvious as compared to up at the pole. or maybe its grounded somewhere else?
Thank you very much for explaining this so well. I have been a refrigeration service tech for 38 years and have never had it explained this well. Two questions. 1. what is the proper color to identify the grounded phase. 2. I was on a job yesterday where an electrician used a 2 pole disconnect and claimed the grounded phase did not need to be disconnected or switched or opened by a breaker. I did not like it but he has been in the field many years himself. I felt the need to follow the professionals advice. What say ye of this ?
Hello Mr. Thompson, sorry for the late reply but I was able to find a little bit of information to your questions. Hope this helps. QUESTION 1: Important requirements for the grounded conductor of grounded electrical systems or services are found in Article 200, which deals with identification of grounded conductors and their terminals. The grounded conductor is required to be an identified conductor of the system or service. Sizes 6 AWG and smaller generally are required to be identified by white or natural gray insulation for its entire length. Sizes larger than 6 AWG are permitted to be identified by white or natural gray insulation; by three white or natural gray stripes along the entire length of the conductor’s insulation, on other than green insulation; or at their points of termination by distinctive white markings that encircle the conductor, such as colored tape or painting. This identification is required for both grounded conductors and corner-grounded delta systems. QUESTION 2: This section contains a list of standards that are applicable to corner-grounded delta systems. These standards address three basic points: 1. Any two-pole circuit breaker intended for use on corner-grounded delta systems shall be tested and rated for such use. 2. No overcurrent device is permitted to be used to disconnect the grounded conductor, unless this device simultaneously disconnects all conductors of the circuit, including the ground. 3. If the system is a corner-grounded delta system and fuses will be used for motor overload protection, a fuse must be installed in the grounded conductor, but only at the motor controller.
@@jasonleary6717 Thanks that helps narrow it down somewhat. Lyndell
😎
35 years as an electrician, i like the layout and demo man, very well explained , corner grounding can get tricky,.
Thank you for the compliment moe molar. I don't have much field experience with this bank myself but you are correct. Everyone says they are tricky for sure.
Exactly what I was looking for. Great demonstration.
Can the iron core be made of solid steel instead of single plates of steel?
It can but, not recommend. Laminated thin sheet allows for more surface area for the current to circulate, therefore reducing eddy currents that can create unwanted heat.
What voltage fluctuations or surges would there be if one we're to remove the ground while under load ?
Very good question koontreeguy. The only info I have read about losing the ground is a relay should set off an alarm or warning that the ground phase has been lost. Most engineering companies stop with their info right there and don't explain the effects of the bank losing the neutral under load. Schneider Electric only explains the advantages and disadvantages of this old type of system (I copied them below). Sorry about not be able to give you a definite answer to your question. Corner-grounded delta systems:•Stabilize voltages of the un-grounded phases to ground.•Reduce the generation of transient over-voltages.•Provide a method for protecting electrical distribution systems when used in combination with equipment grounding. Due to its disadvantages, the corner-grounded delta system has little reason for modern day use:•The system is unable to supply dual-voltage service for lighting and power loads.•It requires a positive identification of the grounded phase throughout the system.•A higher line-to-ground voltage exists on two phases than in a neutral-grounded system.•Most electrical distribution equipment manufactured in North America is not rated for use on this system.•Fault switching (opening) is much more severe for the clearing device, and ratings may be greatly reduced.
I just found out about corner grounded delta transformers and I'm so confused about how you can take a phase to ground and it not behave like a short?
Hello Adam. Thanks for watching the video. Electromagnetic Induction is the whole reason a transformer is able to not "short out" when grounding ONE side of a transformer's coil. Faraday's and Lenz's Law describe a transformers ability to create a CEMF force that opposes the applied voltage. This keeps a delta or wye circuit in balance. A Delta circuit is tying the transformer coils in series. You can always put ONE neutral in a Delta circuit and you will not destroy a transformers ability to create the CEMF force. Two neutrals in the Delta circuit will create a "dead short" across the transformer coil. If you destroy the transformer's ability to produce a CEMF, Ferroresonance will occur. Another crazy phenomenon dealing with electricity. ruclips.net/video/k2RzSs4_Ur0/видео.html Video about Lenz's law ruclips.net/video/U7dNdQc1NL4/видео.html Ferroresonance CEMF
Thanks Jason, they were very helpful!
@@jasonleary6717 hope you can answer but how could we get around this when we connect our 3phase solar inverter on such systems. Will isolation transformers work?
I was wondering about this! Thank you for visually explaining What is happening to cause the effect exactly with the transformer banks?
Thank you for the comment Mr. Klopfer. We hope to have a floating neutral video done in the near future as well.
are those real transformers??? if so that is cool i want one
Hello Marc, Yes, they are a miniature version but everything is made out of 6061 standard aluminum, porcelain bushings and the can is even anodized for safety precautions. The pole mounted transformers can be made anyway the customer chooses. We even make them with single bushing high side and polished as well. The secondary voltage ranges from 120/240V to 277V depending on the customers preferences. All of our equipment can be checked out on our website and thank for checking out our videos. Threephaseinnovations.com.
Great Video
Thank you for the compliment Echo.Whiskey.
I work with so many Corner Grounded 3 W Delta services in the oil fields of East Texas its not even funny. Thank you for explaining!
Thank you for the comment jvck blvck. I can only imagine what goes on in those oil fields. I bet you guys deal with "Phantom or Ghost" voltage in all those straight 240V or 480V DELTA banks all the time. Especially tying them together. Thank goodness meters have a "LoZ" setting now. Stay safe.
@@jasonleary6717 Its bad. We have to really pay attention and watch the younger guys, teach them not to just go through the motions because even though the next bank looks the same, its not. Oh yeah LOZ is a life saver. You should see what the phase angles look like for the pump jacks. Current and voltage are never in unity and PF jumps from .51 to .16 lol you be safe also brother
Thank you Guys! I learned a lot.
Good Video!!!
What if all legs read 120v on a 3phase 208v panel?
Hi Buddy, you have a nice presentation, We have almost the same system in your video , we have WYE Ungrounded- corner grounded delta (3ph, 3wire grounded delta). What is the difference between the WYE ungrounded primary to Wye grounded Primary? The secondary banking is the same.Thanks
Hello Mr. Padilla, Thank you for the comment and sorry it took awhile to get back to you. If you are referring to a "Floating Neutral" it has several considerations. A WYE-WYE bank must always be tied to ground to stabilize the bank. When you have a DELTA secondary and a WYE primary some utilities will want the Primary neutral not grounded on the WYE high side. One reason is when ground fault happens on the distribution system or at the transformer bank itself the ground fault will not go through the transformer bank or the fault won't go back out on the system. In short, it isolates the transformer bank from the system and the system from the transformer bank so fault current will find a different path. If the transformer bank has a fault, it does not go back on the system and might create damage to other equipment on the system. If the system has a fault, it won't ground out through a customer's transformer bank and go somewhere else to ground out. Second reason: When you lose a phase on a closed bank and the neutral is floated the customer will realize they have a problem and will call the utility to let them know something is wrong. If the bank is not floated on the WYE side and the bank is grounded, the closed bank will turn into a "OPEN" bank when a phase is lost. Two transformers in the Delta secondary are trying to carry the original 3 Phase load and if they KVA has not been rated for this type of situation, the customer may not know they have a problem until the other two transformer burn up trying to carry a load designed for three transformers. Example: 3 transformers each with a 100 KVA. Closed bank total KVA is 300 KVA (3 X100). If you lose a phase with the WYE grounded, the bank is now "OPEN" 2 transformer are now trying to carry a 300 KVA load. They won't be able to do it. Their capacity is has been reduced to 173.2 KVA. There are two different ways to do the calculation. 300 KVA x 57.7% = 173 KVA or you lose a phase and are left with 200 KVA x 86.6%= 173 KVA. 2 transformers will try but can't produce the same load all 3 were working together. They will burn up if the phase is not put back in over time based on the load and all other factors. Ambient temp for example. One thing to remember. If you are going to "FLOAT" the neutral. You must connect it to energize the bank. Then you can float it. When you de-energize the bank, put the neural connection back on, then you can open the bank. You will have high voltages on the neutral itself until you make the ground connection. Ferroresonance can also occur and can be dangerous. Whole topic explained very well be Dennis Merchant. ruclips.net/video/U7dNdQc1NL4/видео.html
@@jasonleary6717 Lovely. I am very happy in your answer. It Enlightens me more. That's why when we do V-phase banking, we connect the one lead to the neutral (usually the center one). Our seniors never explain that way. Thanks jason.
@@cristobalpadilla4117 Glad I could help. When we get some time I hope to make a video about a floating neutral sometime soon.
thanks
How would it be possible to change a delta high leg from the meter? I changed a 4wire 120/208 delta high, load center. Upon putting the meter back in the high leg tests 320v to ground and 420v c phase. I grounded&bonded the 4th wire with the ground rod... Just as it was before... I still just can seem to figure out how I could ever change voltage downstream..
Great question, if you are a member of our (lineman transformer discussion page) on Facebook, would you please repost this question their. We have some very smart guys on their. Also this would be a great quest for other members to hear about and discuss. Thanks for the questions.
One a Wye Delta center tap you remove the grounds off of the x2 bushing on the outer cans. What happens if you forget to remove a strap and why?
LUIS LOREDO imagine the one ground center tapped. If a ground is added on either side of the transformer that has been grounded it will result in a ground fault short on that phase.
great video guys. Keep up the good work. It would be nice if you had a better microphone.
Thank you for the comment Mr. Dove. Our buddy who is in charge of the video production is looking into buying a microphone. That building we are in is terrible for sound. DOHH!
how vectors diagram work? can you do a video end explain
We might come up with a video describing the current flow or angular displacement between the primary and secondary coils in a transformer. I will get with our crew and see what we can come up with in the future. Thank you for your reply Mr. Barajas
Long be the high leg. Down with the wimpy Wye (120/208).