Solving Series Transformers Problem with Lumped Resistance

AI Thread Summary
The discussion centers on the unexpected current measurements in a lab experiment involving two toroidal current transformers (CTs) with different turns ratios. The observed current does not align with the expected values based on the turns ratio, suggesting a need for further analysis. The inquiry raises the question of whether complex models or lumped wire resistance should be applied to understand the situation better. Key considerations include the opposition of Kirchhoff's Voltage Law (KVL) in the secondary and the efficiency of the transformers, which is influenced by frequency, windings, and core material. The findings imply that if the transformers were magnetically coupled, a more average current could be anticipated.
MRKN
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This is a problem I stumbled upon after noticing a pattern in the lab- the measured current was never quite what you'd expect from the turns ratio of either transformer alone, but somewhere in the middle.

I used 50:5 nominal turn toroidal CTs with 15 turns in one CT primary and 5 turns in the other primary.

This is not a homework question but rather an inquiry as far as whether or not I'd need to use complex models to analyze this situation, or rather lumped wire resistance.

To get a good start, notice the opposition of KVL in the secondary with the dot convention. This suggests zero flux in the transformer with the lesser amount of turns and thus simply Is = N1(Ip).
 

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Cannot be answered without knowing transformer efficiency (function of frequency, windings, core material).

An average current would be expected if the two transformers were magnetically coupled and behaving as one large transformer. Cheesy E-lams at 50-60Hz have a huge field...
 
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