Transformer configurations

I’m a high voltage apprentice and I see larger transformers almost everyday this is a extremely well made video describing how these transformers work especially for people even less experienced than me well done

Learned so much... Ryan you're quickly becoming my favorite teacher. Thank you so much for what you do for our industry.

Great video I might have to watch it over and over , but definitely getting more and more familiar with transformers , thanks !

Thanks Ryan from a retired master electrician from Wisconsin....I don’t do this stuff anymore but I have had a love affair with electricity for 45!years and I enjoy your video’s

In my 50 years never saw a corner grounded Delta transformer. You mentioned that you are not allowed to fuse the corner grounded wire but would a 3 pole circuit breaker be okay. Had at least 40 hours of transformer in vo tech class back in the 60's but do not remember that. Helped my sparky dad install a 2300 volt service to a Scott T transformer that put out both 2 & 3 phase voltage. The electrical vault was very small and only had room for 1 transformer. Kind if remember that open Delta does not provide as good as a voltage regulation but the ultily companies love them due to increase available setvice only have to install a third transformer.

Thank you for this Ryan, appreciate the effort to put it together.

I thought Transformers were robots in disguise just kidding thanks for the wealth of knowledge you share

Thank you Ryan Jackson, keep up the hard work! Have been watching all your videos and appreciate every single one of them. Here located in the Richland, Washington (Hanford area). Come visit us sometime

Ryan thanks for another great vid. Was told a few years ago at a continuing education class that it is very important to do an availble short circuit calculation whenever replacing the customer owned transformer espically when using the now lower impedance transformers. Also have to be carefull with large services. At large hospital that I retired from somebody pulled out some spare 600 to 1200 amp 480 volt circuit breakers while performing yearly PM'S & testing that were only rated for think it was 65KIA and installed them in other switchboard that was feed from another dual rated setvice but with had think it was 600 to 1200 amp breakers that were rated for at least 90 KIA thetefore limiting that switchboard to only 65 KIA or in other words the lowest avaible KIA. Took boss a while to belive this serous mistake.

Wow. Very cool video, I wished you were my former instructor in the electronics class I attended all too many yrs ago lol. I never understood the concept of two phase five wire or how it was hooked up, or that it is still in service near Philadelphia area, I have only heard of it, and that it was pretty common in the 1890s to very early 1900s, i think the first poly phase system invented by Nicola Tesla used the configuration to power some very early electric motors, but was soon phased out to more efficient 3 phase systems that we to this day, still use.

Excellent presentation!

Single Phase 2W systems are actually very common in North America if you work with Control Transformers, or in a panelshop. Typically in the 100-2000VA size, 600-120V (Canada) and 480V-120V (USA). Great presentation!

Thank you. I really enjoyed this one. I never knew of 2 phase in USA.

remarkable and informative good sir, thank you for taking the time and presenting knowledge in a concise and understandable format for us everyman.

Excellent explanation. Thank you

Thanks. This is great info

Only problem with a ungrounded system that has the 3 ground indicating lights is trying to locate a ground. We had this back in the 1970's at a large slaughterhouse that I worked on. Could only really work on finding a ground was on Saturday when there was no production. Would start in substation turning off 400 to 800 amp breakers then going downstream. Majority of the time is was from a grounded motor. At that place we replaced at least 1 to 3 bad motors a week. Record was replaced 3 bad 100HP motors on one very hot day during a ultily brownout. I had my last long transformer class 50 years ago so I think they told us with an open delta voltage regulation was not as good as a closed delta.

Thank you Ryan.. I was always confused about all the different types of systems out there.. I found your channel because I was trying to learn about .. Swimming pool safety.. through Mike Holt videos .. I have learned so much information from the both of you .. Thank you so much

great,video RYAN,thanks,casanova EC

Thank You Ryan!!!! Watch your videos every night after work.

Installed a 3 phase & single phase service to a Philly store about 10 years ago. The area still had 2 phase power. Ultility company installed a phase changer then if memory served me right only brought in 5 wires. One conductor was used for the single & 3 phase service. Bad thing about 2 phase if you cross feed wires to a 4 wire 2 phase motor it would only recieve around 180 volts instead of 240 volts burning motor out. At the large hospital/ research centers that I retired from probably had over 200 480 to 120/208 Delta to Wye transformers. They had a few 208 to 240 volt transformers for some small equipment. Thanks for another easy to follow informative vid.

Fantastic video. I learned a lot from this.

Transformers, more than meets the eye.

Just when I thought I understood that single phase = 120/220 volt, center tapped transformer, you go and shake up that assumption. I'm not a sparky, but always been. interested in electrical/electronics. There's already lot of misconception out there with referring to 220v as being 3 phase. Especially in buying equipment: people love to refer to 220v motors as 3 phase... The rabbit hole runs deep!!!

In the three phase high leg Delta example, where the B phase is the high leg, (14:46 min in video) the 208 V circuit to ground could be useful for some 208v lighting circuits or even a single phase mini split HVAC unit rated for that voltage. Once the conductor leaves the panel, it would be no different than any phase conductor on a 208/480 used for lighting loads in commercial applications…. What hoops would you have to go through to be able to use that phase for single phase loads?

Thanks ryan. If transformer not grounded, is it functioning properly?

Ryan I have a question on autotransformers and what you mentioned the 20% general rule. So if single phase autotransformers only have 3 wires what would the 4 wire ( extra conductor for gounding conductor = white wire ) that our ultilty company uses be called? They only provide 1 wire from the 13, 200 three phase on a pole to step down the voltage down to 120/240 volts. They ground one side of medium voltage to transformer case, a flimsy ground rod at bottom of pole and to what appears to the center tap on secondary to grounded conductor. To me the ground rod would never have low enough resistance to feed majority of current for primary winding so grounded conductor along with our copper water service and metal gas pipe is back feeding current to feed transformer. Cracks me up how ultily company gets away with splicing ground wire 3 or 4 times that only runs 30' down the pole. Wire from transformer starts out as copper that somebody stole a 6' section. Then they climbed up and stole a couple of more feet of copper. Luckily they use aluminum to replace the copper and that lasts longer. Thanks.

You may be aware that in New York City (and possibly Westchester County??) Con Ed distributes two legs of their three phase network 120/208V wye system to "single phase" residential households. Two phases (208V, not 240) and the neutral. Your neighbor may well get one leg of the third phase and one of the same legs you got. Most people are unaware of this, although I'd assume that any licensed electrician in NYC is. I've had to explain this to many of my EE friends who couldn't understand why the supposed 240 volts between the two hot legs of their service only measured 208V. If you are in a part of NYC with overhead distribution, it is very visible, four secondary conductors with only three connected to each service drop, a different three (but always the neutral) to each drop. Second item of interest: At a university on Long Island I worked for in the 1970's the original university owned primary and secondary distribution was two phase five wire. The primary was two phase three wire, two 2400V legs and a ground return for the two of them. The transformers for each building were two (very old) single phase transformers each with a 120/240V secondary as you drew. The campus was built new in 1929, so I'd have to guess that the utility distribution in the area was two phase, but I was never able to find the history. LILCO, the then utility fed us with a pair of scott-tee transformers from their (then) 4160V three phase delta primary distribution to our 2400V service. While I was there, we rewired the remaining buildings with "more modern" 120/208V three phase distribution fed from a new 13KV service. However the cafeteria was full of two phase four wire (no neutral) motors, and rather than rewinding or replacing them all, a 120/208 to 240V three phase to two phase scott-tee transformer was installed to feed them all. My other involvement with two phase power and scott-tee transformers was with mercury vapor rectifier banks. Both low voltage (carbon arc lamp supplies for 35mm motion picture projectors) and many KV supplies (for broadcast transmitter tubes) often used scott-tee transformers with four rectifier tubes.

If there is a neutral wire on a wye 480/277 secondary, does the wounding has to be grounded ? Can that neutral be floating? And why? Thanks! Very good class.

Where can you get a straight 240v breaker to buy

Hey Ryan, it seems like the math works the same on the open Delta system using the Pythagorean theorem to get 240v between the two points on the open end. It’s just a little confusing to me that you can get 240v between the two points on the open ends. And use the math the same way if you were to draw an imaginary line between the two open points. Or am I over thinking it?

I'm a new subscriber sir, can you explain how secondary 3 phase 3 wire system is derived from transformer bank with single phase primary? Thank you

Although I have an _”ancient”_ (1976) degree in electrical engineering, I do have one question: In an area where both 12 Kv and 4 kv distribution systems are used, as a rule of thumb, is one more susceptible than the other to subjecting the end user (120/240v, 1Φ, 3 wire, overhead) to lightning and/or switching surges? For example, would a lightning strike (direct or indirect) to a 12 kV line get stepped down in voltage more before entering a home than a similar strike to a 4 kV system? Or does lightning not obey the usual mathematics of a transformer’s turns ratio?

Open Delta: Understand now. All three (3) power company phases are connected to the primary coils (2) even though only (2) coils in the SECONDARY side of the transformer(s). 54% as powerful as closed delta system. Thank you.

On the 3 single phase 4 wire system , the grounding wire coming down the pole from the 3 single pole XMFRs, If that ground wire got cut by a vehicle accident, what would it do to the voltages ?

HI,,,RYAN,question is permit make the raceway inside the transformer in the pads concrete????may i use PVC,i have seen in miami building but im not sure is legal????CASANOVA ELECTRIC CONTRACTOR

Every videos helps

North America, do we use SWER (single wire earth return) from the (single phase) step down pole mounted transformer to the substation? I see no neutral from the transformer(s) thank you

The ground SCREWS to the underside of the transformer. If this should break, is that big trouble?

Geez and I thought I knew everything about transformers

I got to the end of this video, disappointed because I didn't see the configuration for which I was searching when I clicked. The configuration I was hoping to see is the one that enters a residence (i.e., 120/240 grounded). Did I miss it?