[Boatanchors] [T-368_BC-610] FS: KW Isolation Transformer

[Rob Atkinson]

When I got home from work I did an experiment.   I plugged in an
isolation transformer to a wall outlet (my line v. is up to 128 v.
now!) and got out my Fluke 115 and measured 128 v. from one end of the
secondary to the other.  I put the fluke on the "hot" side of the
secondary and the outlet box metal ground and measured about 82 v.  I
measured my body resistance from one hand to the other as about 1.5
megohms.  Then I held the fluke probe connected to the isolation
transformer secondary "hot" and put my other hand on the outlet box
and saw the v. on the meter drop from about 82 v. down to 17.  But I
felt no current through my body at all.  So evidently I am mistaken
but I don't know why I didn't feel any current when the v. dropped so
much.   Well, I guess 65 v. / 1500000 ohms is a very small amount of
current, too small to feel.  The 1:1 isolation transformer must
provide only the current the load uses and no more.   That is the key
thing I was missing I think.

73

Rob
K5UJ

On Fri, Oct 16, 2015 at 11:48 AM, Francesco Ledda <frledda at att.net> wrote:
> A transformer will have the secondary floating respect to your home ground;  therefore, touching one terminal and ground will not have a current path.
>