DIYbanter - View Single Post - Estimating the Number of Turns of an Inductor

On 6 Jun 2004 10:32:44 -0700, (Tom Bruhns) wrote:

"Phil Allison" wrote in message ...
"Reg Edwards"

But the primary-to-secondary coefficient of coupling, with the leakeage
reactances, is accurately KNOWN from the start of the design.

** Leakage reactance is irrelevant with a no load test.

You'll get a lot of disagreement with that; even experiments will
disagree with you. (One way to think about it is that the applied
primary voltage is split between the leakage inductance and the
perfectly-coupled inductance of the model. There's no drop across the
secondary's leakage inductance, but there for sure is across the
primary's leakage inductance.) But as Tony W. so kindly pointed out,
it's much less important if you use a short-circuit (current ratio)
test.

Cheers,
Tom

Leakage inductance will diminish both voltage and current ratios. If
not, a 1" diameter 1-turn coil driven by 1 amp could induce an amp
into another 1" ring a mile away. Tesla would have liked that.

John