There's a subtle but fundamental flaw in the calculations. The phase currents were calculated before the neutral wire was connected. Without the neutral wire connected the load phase voltages are not 120 volts each. For load A, the phase voltage is 111.9 A, 2.41 degrees and Ia is 22.38 A, etc. Currents are only as calculated when there's a neutral wire connected.
@ZackHartle
3 жыл бұрын
You're totally correct! I just forgot to draw it right at the beginning like I meant to. Good catch!
@soldatheero
3 жыл бұрын
I don't understand the end bit how he calculates the current angle. i understand the pyth theorem to get the magnitude but how does he know to place it there? "like i said we go over.. and down" not sure what he is talking about
@narayant715
Жыл бұрын
How can you treat a situation where there isn’t a connection between the neutral points of the transformer and load?
@josho5177
3 жыл бұрын
Thanks for the video Zach. I have a question regarding neutral current sizing. 4-018 1) tells us the neutral must be sized in order to carry the unbalanced load. 2) tells us the "max" unbalanced load shall be considered to be the max connected load between the neutral and any ungrounded conductor. So when we're sizing neutral conductors do we use the calculated neutral current (like what you demonstrated here) or is 2) specifying that we use the total ampacity of the load on the largest phase/leg? If so, then isn't that connected load subject to change if we add more loads in the future? The way I'm reading this it doesn't seem like it wants us to use the ungrounded conductor ampacity but rather the "connected load" ampacity to size the neutral. Seems odd. Hope that's coherent, thanks again.
@josho5177
3 жыл бұрын
@@ZackHartle ah thanks!
@soldatheero
3 жыл бұрын
"we end up being 12.4 amps below zero mark" where is he getting this number?
@ZackHartle
3 жыл бұрын
Hi there, so it all has to do with the HV chart. I ended up with a positive horizontal value and negative vertical value, so that's how I know to go to the right, and then down. It's a little tough to explain, but here's two other videos that might help: kzitem.info/news/bejne/wJeFzKh7n6t5mn4 kzitem.info/news/bejne/opunl6SZnoqEiqg
@gamelover2594
2 жыл бұрын
i have a question if you are dealing with resistive loads why don't the vertical number for current in your table are not zero because practically we don't have neither inductance or capacitance in this circuit?
@ZackHartle
2 жыл бұрын
Because we have multiple reference points now, so the currents are in-phase with the voltages. However since the voltages aren't at 0 degrees, there is a vertical component. Should be in-phase with the voltages that create them though
@ikokochibueze2224
2 жыл бұрын
What is a hv chart
@ZackHartle
2 жыл бұрын
Take a look at kzitem.info/news/bejne/wJeFzKh7n6t5mn4 and kzitem.info/news/bejne/opunl6SZnoqEiqg
Пікірлер: 13