zapping NiCAD Cells

Roger Hill rhill at siue.edu
Sun Jul 20 14:49:48 MDT 2014


Interesting; I hadn't heard of doing that before.  This avoids having
to convert to DC!  I guess the resulting magnetization depends on
which peak of the AC blows the fuse wire, whcih would depend on things
like when and how fast you plug it in:  On a time scale of the period
of the waveform, the plug-in connection might be established
relatively slowly, so it might take several cycles for the current
wveforem to build up to where it blows the fuse wire.

-- Roger

------------ On Richard S's message ------------

> You reminded me of the old procedure for magnetizing an iron bar.
> Wrap it with heavy insulated wire, and wire it in series with a much
> finer wire that acts as a fuze.   Then plug it in.   Current rises
> as rapidly as the AC power waveform and the inductance will allow
> until the fine fuze wire blows. The current gets very high, more
> than enough saturate the iron bar beyond its magnetic capabilities.
> 
> The fuze wire must be fine enough to blow in a small fraction of one
> cycle of the 60 Hz AC power.
> 
> I tried this method when I was about 15.   My dad smelled the burned
> wire and came running in.   When he saw what I had done, he was
> really angry. But the house circuit breaker did not blow.   I guess
> my fine fuze wire was fine enough.



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