Hi...keen amateur here......don't crucify me for asking!! I understand Ohm's law and I understand the mechanics of measuring end to end on ring final and then joining incoming live to outgoing neutral etc, and I know that this configuration gives a figure of 8 (in fact can be straightened to give a complete circle) but I can't figure out the "calculated method" of dividing by (r1+r2)/4....why?
If you meter across the mid point of the "circle" then yes...
if K= r1+r2 (the complete circle) then...since in parallel...
1/R = 1/(K/2) + 1/(K/2) which simplifies to 1/R = 4/k, then R=K/4....(r1+r2)/4........but what happens if you measure across the circle at any other point other than the mid point?
 
Hi...keen amateur here......don't crucify me for asking!! I understand Ohm's law and I understand the mechanics of measuring end to end on ring final and then joining incoming live to outgoing neutral etc, and I know that this configuration gives a figure of 8 (in fact can be straightened to give a complete circle) but I can't figure out the "calculated method" of dividing by (r1+r2)/4....why?
If you meter across the mid point of the "circle" then yes...
if K= r1+r2 (the complete circle) then...since in parallel...
1/R = 1/(K/2) + 1/(K/2) which simplifies to 1/R = 4/k, then R=K/4....(r1+r2)/4........but what happens if you measure across the circle at any other point other than the mid point?
Figured it out..see image...attachedView attachment 50817View attachment 50817
 
Figured it out....this image says it all..
why_divide_by_4.jpg
 
Hi...keen amateur here......don't crucify me for asking!! I understand Ohm's law and I understand the mechanics of measuring end to end on ring final and then joining incoming live to outgoing neutral etc, and I know that this configuration gives a figure of 8 (in fact can be straightened to give a complete circle) but I can't figure out the "calculated method" of dividing by (r1+r2)/4....why?
If you meter across the mid point of the "circle" then yes...
if K= r1+r2 (the complete circle) then...since in parallel...
1/R = 1/(K/2) + 1/(K/2) which simplifies to 1/R = 4/k, then R=K/4....(r1+r2)/4........but what happens if you measure across the circle at any other point other than the mid point?

Using live and neutral will give R1 + Rn not R1 +R2
 
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Can't figure ring final r1 + r2 divided by 4
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KeenPensioner,
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KennyKen,
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