Thank you for taking your time to make these videos. I graduated from a line school and did exceptionally well in the classroom portion, but none of the instructors could ever teach vectoring in a way that made sense to me. I was always able to get by using / drawing out the physical connections on transformers and just never used vectoring. 2 years later I’m finally about to start an apprenticeship and I’m circling back to refresh my knowledge and focus on weaknesses. Your videos are incredibly helpful - the visual references you use and your method of teaching are top notch. This float vs tie topic was another one at school where instructors basically left it at “that’s just how it is,” and didn’t explain further. I don’t like memorizing things, I want to actually know why we do things and why it does or doesn’t work, so again thank you! Really helpful videos
That’s Awsome. I’m glad the lessons are helping. If you ever have a question or need something explained further email me at hilineacademy05@gmail.com. Stay safe 👍
Great demo... and I love your transformer pad mock-up! VERY cool. 40+ years in the electrical trade (semi-retired now), but it never hurts to refresh the ol' brain cells. Thanks!
Hey I just found your channel and I must say thank you for giving such great information. I’m an apprentice lineman, and you’ve been so helpful. You just gained a new subscriber! 😃
Why didn't you mention the number 1.73 (square root of three) as the multiplier / divisor for your voltages at a 120 degree phase angle? That's the one most people use 99% of the time (Unless you're working on an old 2 phase building in Philly) Don't get me wrong, you made a great video, but 1.73 is a real handy number to remember
Ya I hear ya. I didn’t mention it because I already had a lot going on in the lesson. It is a great way of explaining where the phases to phase and phase to neutral relationship comes from. 👍
Can you please explain why it was necessary to parallel the coils (alley cat bad dog the coils)? i.e. if the transformer name plate shows 120/240, and the customer need is 120/208, how did you know that you had to alley cat bad dog the coils?
Its just a chalk board anything works and anyone can make mistakes Edited I think the secondary coils need to be parallel internally or use a single winding secondary transformer less hastle . 🤔 impidence boosts voltage when floating the neutral 17:00
You can hear feroresonance as soon as you break the neutral connection. Excellent video. Would be interesting to connect a fluke scopemeter and see the 3rd harmonics that are raising the L/N voltages 15-20 % Working on a project where MOV's are blowing up on a rockwell vfd fed from a wye/wye xfmr bank. I think you may have solved my problem.
Yes sir. We had a commercial customer that had some giant well heads. They kept blowing vfd’s and the problem ended up being voltage imbalance due to a regulator bank having one of the regulators stuck. I have also heard of vfd’s blowing when the primary feed was extremely long. The voltage was balanced but it ended up getting so high due to the reactive properties of the underground that the vfd’s couldn’t handle it. I’m pretty sure the fix there was to add an inductor bank to fix it. Please keep me in the loop it would be interesting to see what the problem is. Stay safe and keep up the good work. 👍
Hello, what would happen if the secondary is floating (ungrounded and not tied to primary neutral)? And by "circuit neutral" do you mean the neutral wire from the utility?
My friend from class forgot to bond secondary neutral (wye-wye) to primary and got shocked from touching secondary ungrounded neutral conductor. Why did the secondary neutral became hot?
Great question. So first off. If the secondary neutral isn’t tied to the circuit neutral,but is tied to the transformer neutral, the customer wouldn’t see any change in voltage. The secondary circuit is separate from the primary circuit. Secondary voltage is dependent on the secondary bushings used to supply service. If the service neutral isn’t tied back to anything and is completely floated, meaning the customer is only being fed the two secondary phases, the customers 120 circuits would see 240 volts due to the only return circuit back to the transformer would be the other phase. And yes the circuit neutral I’m talking about is the neutral from the utility. Stay safe. Keep learning. 👍
Yes sir. When your customer needs a wye secondary connection to meet their voltage needs and the transformers your banking have two secondary coils you’ll have to parallel the secondary coils so that you will be using the full Kva of the transformers. I did a video lesson called” alley cat bad dog” that explains it all in detail. Stay safe. 👍
Nice, i always thought of the 1.732 for phase to ground. But hear is my question what about a high impedance neutral. 50 ohms is what i remember. Thinking it would be the same of your demo since the secondary is what gets the resistor. Was thinking Kirchsoff law might come into play. Thinking i may have answer my own ?
Thanks for the encouragement brother. I appreciate it. Lol that’s going to be the next lesson I do. We’ve had some life things happen and I’ve been pre occupied with all that stuff but that is next on the list. Stay safe and if you need anything give me a ring. 👍
There is a path back to the substation. But when the neutral IS TIED down to circuit neutral, the return back to the sub is the neutral. BUT when you FLOAT the primary neutral connection, current flow back to the sub changes, and now the return current is returning on the other phases.
@@hilineacademy8482 Well, there are no other phases on my transformer(s) for the current to balance out. Only ONE phase service on the WHOLE BLOCK. 50 houses all share it. Every transformer is ONE BUSHING as you state this (float neutral) Multi Point Grounded Neutral at EVERY POLE that has a transformer. thank you. “ Correct myself, one bushing transformer DOES NOT mean floating the neutral.
@@tedlahm5740 I think I’m seeing where your getting confused. The lessen ”wye wye you always tie” is referring to when your building a THREE POT wye- wye bank. You cannot float the primary neutral connection on a single phase transformer. You will not have any current flow going through your primary coil, and therefore have no secondary voltage. Again, you cannot float the primary neutral connection on a single phase transformer.
@@csandoval82 Thank you. Further question. On my single phase step down transformer. The primary coil is grounded at the bottom of the pole. What happens if anything if this grounding cable should be BROKEN due to an accident? Interesting side note ( power company uses 3 wire 3 phase distribution system. no parallel neutral back to substation) thank you PS. I understand now, can not FLOAT the neutral because I have no secondary phase to balance out the load.
