Three Phase/ Four phase

[GoldDigger]

Neither of us are right, the resultant is the inverse of √I_a²+I_b²

I_n = 1/√I_a²+I_b²

...assuming pf 1.

Look at some special cases Tony: if In equals zero your formula says In = 1/Ia. Clearly wrong!

 

[GoldDigger]

What you are describing works for MWBC... but not neutral anything.

The words of the definition do not specify what a wye point is. In the case of a three wire two phase system the wye can look a lot like a vee. Do not rely on the wording of an Informational Note to "correct" flawed or ambiguous language in the actual Code.
If "polyphase system" implies a complete vector circle, e.g. two phase must be four or five wire,, then your analysis is correct.

 

[Smart $]

Neither of us are right, the resultant is the inverse of √I_a²+I_b²

I_n = 1/√I_a²+I_b²

...assuming pf 1.

I don't think so... :happysad:

It's basically just Pythagorean's Theorem. If you start with both vectors tail to tail, move one (without changing direction) so its tail is at the point of the other... simple vector addition results in magnitude and bearing from the unmoved vector's tail to the moved vector's point. PT solved for hypotenuse gives you magnitude without bearing.

 

[Smart $]

The words of the definition do not specify what a wye point is. In the case of a three wire two phase system the wye can look a lot like a vee. Do not rely on the wording of an Informational Note to "correct" flawed or ambiguous language in the actual Code.
If "polyphase system" implies a complete vector circle, e.g. two phase must be four or five wire,, then your analysis is correct.

Nice try but I will not be moving to your campsite.

 

[GoldDigger]

Nice try but I will not be moving to your campsite.

That's fine. That way I will not have to charge you rent for the building (structure) there. (Which is a post in the ground.)
(Snide reference to another thread.)