"Lloyd E. Sponenburgh" lloydspinsidemindspring.com writes:


A point to note that amazes me some people don't know.... with
electric current, the point of HIGHEST resistance will be the point of
highest heat(ing). Think about it.

I did. It doesn't. I'm a career electrical engineer, now 'converted to
the dark side' (explosives industry).

Got a slot for me? [TBP/EKN]

IF you even understand Ohm's law, consider that a few hundred megohms in
series with (even) a 575V main won't conduct enough current to even warm
up.

That's a "HIGH" resistance. A complete "open" with no conduction at all
would be the "HIGHEST" resistance. And in that case, no current would
flow, at all. No current, no power dissipation -- no heat. So
obviously, the point of highest resistance does NOT create the highest
heat.

The trouble is, the folks teaching fables ignore the major factor:
We have constant voltage supplied by the grid, not constant current!
{In some parallel universe, maybe that's not true...}

{I've used i instead of I to avoid 1|I confusion.}

With a constant voltage source, the i is a function of the R,
and the P is a function of both. If you think constant current,
then R is the only variable factor and yes, higher R is more
power.

Now in reality, the common case RCM types need to think about
is sorta both/neither. Rather, a motor tends to draw constant
power for a given load, and very roughly constant current. Now,
a {maybe loose} connection in its plug has zero to n ohms. At
zero ohms, i^2R is zero; at 1 ohm, 1*i; at 2 ohms 4*i, etc. This
because that resistance is inconsequential in setting the motor
current but IS important in the power dissipated.

.....Now if n gets SO big that the current falls {and of course the
motor stalls/never twitches}...

And THAT is why poor {0 ohm} connections in plugs&splices are Bad Ideas.


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