Current Transformer 1

[pakiengg]

Hey guys ! Assume there is a balanced 3 phase load drawing 5A in each phase. If we attach a measuring CT around any one phase then it will show 5A. If we thread all the 3 phases through the CT, it will show 0A. What will it show when we thread only 2 phases through the CT and why ?

 

[waross]

Homework??

Bill
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"Why not the best?"
Jimmy Carter

 

[pakiengg]

Hahaha ... no just wondering

 

[Skogsgurra]

What have you been thinking so far? And how do you reason?

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[pakiengg]

well i tried this with a clamp on meter and it gave me the same result as it showed me with one phase ie. 5A. Cant figure out the reason.

 

[Skogsgurra]

The clue is BALANCED. The current flowing in two phases produce the same magnetic field as the current returning in the third phase.

They are both 120 degrees out of phase and if you add them vectorially, you get a single phase current that has the same magnitude as the third phase and is 180 degrees out of phase with it.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.