Great video explaining what we're covering at college this week. Really helps keep it fresh once we've left the classroom environment. Thanks for the content !
add me to your list of students when they learned the last method. i shared your videos with my classmates and they learned just like i did... hopefully. this video really helped. thanks much
Thanks Joe, well explained. Apart from "exam for exam's sake" why would you inflict method 1 or 2 on anyone? Presumably method 1 gives the definitive "correct" neutral current, the other two methods being an acceptable "rule of thumb"?
Method one combines accuracy with a visual representation of what's going on which is the best of both worlds really. There is another formula that you just stick the numbers in but it doesn't generate any understanding of what's happening in the circuit.
Excellent explanation. What will happen when we remove nuetral in imbalance load in star and what will happen we remove any one of the phase in delta connection?
This is a great video, Joe but just need to watch the direction of the neutral current phasor in this video and its predecessor. In order to satisfy Kirchhoff's Current Law at the neutral point it is effectively -In we are solving for, not In. Your methods will, of course, calculate the magnitude of the neutral current correctly but the direction of the neutral phasor is only shown correctly at the end of this video (i.e. "pointing toward the neutral").
That's a really good point actually, I took it to this point because Level 3 electrical requires you to find the magnitude not the angle, but I'll do another vid explaining the next step. Thanks for commenting. 👍
@@JoeRobinsonTraining really wish I’d had access to your vids 35 years ago when I was training as an electrical engineer. You are very good at explaining these concepts.
That is a good question. Not in recent memory but I'm struggling to go back over all the iterations of the electrotechnical qual. 🤔 Currently I believe C&G state either method is acceptable. EAL, I think, ask for a phasorical method. I'd need to confirm with the documentation though.
The neutral current is actually reversed from how he drew the vector in this video. Neutral current needs to cause the current among all four wires to add up to zero, which means it is the reverse of the vector sum of the three phase currents.
Hi Joe, just catching up with your training videos. If i were to use CAD with this method, not for an exam of course, would the answer be spot on and as good as your first example by calculation.
How do you calculate the neutral current when there is a PV system and there is net energy export on one phase and import on other phases? How do you draw the vector when it represents net energy being exported to the grid on a phase? For example, let's say there is 10A export on L1 / 18A import on L2 / 0A on L3. I measured about 25A in the neutral in this situation with a clampmeter but that seems very high... PS: I know this video was posted 4 years ago, but thought I'd give it a shot anyway...
Very easy to calculate the neutral current without all this drama. In a balanced source (I'm assuming you have a balanced source) The source currents are 120 degrees apart so Line 1 is 4
I don't understand in what situation a phasor diagram method would be preferable to a vector diagram method (your triangle method). I have always been taught through school to use the vector diagram for graphical representation of resultant forces.
Just seen the phase diagram drawing of the star and delta 3 phase motors. Now I understand! When there is a lot of vectors of a single variable the vector method is easiest, when there is loads of different variables the phasor method is easiest to work through.
It was this stuff Joe, I've still got my old notes and I checked. I really like your channel and I'm watching your vids daily. Thanks for making these vids, please use a pen, I have to really strain my eyes to make out the pencil😄
Let A, B, C the currents, we have I = Asin(x)+Bsin(x+2pi/3)+Csin(x+4pi/3). This can be simplified to sqrt(A^2+B^2+C^2-AB-BC-CA)sin(x+Φ). So, sqrt(A^2+B^2+C^2-AB-BC-CA) is the formula.
You like to draw. You could just put the values in a program. Nothing is actually learned from these drawings. Maybe you were supposed to be a draftsman.
I do like to draw. I could have put the values in a program. These drawings help you visualise how the differing currents affect each other. Maybe I was supposed to be a draftsman!
