Re: [TenTec] Slightly OT: Sunspots for propagation? Who needs 'em?

[Jim Brown <k9yc@audiosystemsgroup.com>]

I'm not sure what you mean by "intelligent power management system." But 
think about the fundamentals of how this might be done. You've got to 
reshape the total load current in each phase to make it sinusoidal 
without increasing the total current drawn! Things like this may be 
possible, but something like this is not cheap. The EU has regulations 
about this that apply to large systems, and it costs a lot to comply.
73, Jim K9YC


On Sat,8/27/2016 10:58 AM, Gary J FollettDukes HiFi wrote:
> And you don’t think that intelligent power management systems available today 
> could correct for this?
>
> Gary
>
>
>
> > On Aug 27, 2016, at 12:30 PM, Jim Brown <k9yc@audiosystemsgroup.com> wrote:
> >
> > 3-phase power is not the universal blessing that you believe it to be. The overwhelming bulk of the power 
> > delivered to today's homes is to electronic loads, which draw highly distorted current, resulting in very 
> > high harmonic content. That, in turn, results in high neutral currents that consist of "triplen" 
> > harmonics of the fundamental rate (50 or 60 Hz). Triplen harmonics are those whose order is a multiple of 3, 
> > and they add in the neutral rather than cancel, even with loads that are perfectly balanced. Those harmonics 
> > also add in the "green wire," producing the characteristic "ground buzz" (180 Hz, 360 Hz, 
> > 540 Hz, 720 Hz, . . . ), as opposed to hum (50/60 Hz).
> >
> > Neutral currents in 3-phase systems can easily exceed the current in a phase conductor. 
> > Neutral current is what started the very real "Towering Inferno" and burning 
> > insulation running up cable risers carried the flames.
> >
> > 73, Jim K9YC
> >
> > On Sat,8/27/2016 1:37 AM, Gary J FollettDukes HiFi wrote:
> > > Only politics, and the relentless battle that power companies wage every day to 
> > > avoid capital investment in new power delivery apparatus.
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