309 written exam. Neutral current in an unbalanced 3 phase system.

[Ste69]

Cheers for the link mate.

ill have a read over my notes tomorrow when im revising again.

 

[Simonslimline]

Cheers for the link mate.

ill have a read over my notes tomorrow when im revising again.

No worries.

Good luck with the exam

 

[Ste69]

No worries.

Good luck with the exam

Cheers..........just tried a mock exam and didnt do to well, just couldnt put my finger on the answers, right on the tip tho.

 

[Silly Sausage]

Had the 309 science and principles exam today at college and had a question on calculating the neutral current flow in a 3 phase 4 wire system with unbalanced loads. The formula is below, and definitely one to memorise.

N=√((A²+B²+C²)-((A×B)+(A×C)+(B×C)))

There's a much easier equation to use, see Annex A722.1 in Amendment 2.

The condition being that the phases are near enough 120 degs apart.

 

[Simonslimline]

Cheers Archy

 

[Silly Sausage]

Oh aye, in case you didn't know already, as an aide-memoire; 0.866 is root 3 over 2.