Current Flow in shorted CTs

[dejjones]

Some colleagues, whilst doing primary injection testing, measured currents in unused shorted CTs. The CTs were 1200/1 with a centre tap, and all connections were shorted together. All results were as expected except in one CT they measured appreciable current in the centre tap wire, and unbalanced currents in the 2 outer wires. A discussion as to the likely cause of this raised the following question which we were unable to answer.

If we had a 1200/1 CT with with a NON centre tap (eg 1200/800/1, say)and we shorted all terminals, how would the secondary currents be distributed?

Can anyone help here?

 

[VisiGoth]

Now you have a coupling factor problem and need to know the resistance. If the coupling constant was unity (impossible) adn the resistance was zero (impossible), then I guess the universe would end.

The amp turns would try to stay the same in each loop. Since the resistance per turn should be nominally equal, and we would hope the couling of each turn to all of the others are the same, then you would never have any current flow in the centre tap, wherever the tap might be as long as there was zero reisistance between the two end taps.