Re: [TCML] My first tesla coil

[Bert Hickman <bert.hickman@xxxxxxxxxx>]

Hi Dex,

Yes. AC induction can be deadly for linemen working on otherwise 
disconnected lines that parallel energized lines. This is especially 
true with high voltage transmission lines. Unenergized lines are first 
always grounded to prevent accidental electrocution from otherwise 
seemingly "dead" lines:

http://www.youtube.com/watch?v=KoPW_IgeRN0

The induction field can also be artistically "mapped" near transmission 
lines:

http://www.richardbox.com/

If you park a vehicle directly under one phase of a HV transmission 
line, you can sometimes feel a distinct "nip" when barely touching the 
vehicle. Induction can become a significant problem with metal fences or 
large metal buildings that parallel transmission lines.

HVDC transmission lines can also induce annoying voltages onto nearby 
objects via electrostatic induction and ionic currents (single-polarity 
corona charging). For example, during tests by the Electric Power 
Research Institute (EPRI), voltages of 10-20 kV (and sometimes 
considerably higher) were commonly induced on vehicles parked 30 meters 
away from a 600 kV negative monopolar line. Although not as prevalent as 
AC transmission lines, DC lines are a critical part of our power grid. 
See for example the +/-500 kV Pacific DC Intertie:

http://en.wikipedia.org/wiki/Pacific_DC_Intertie

Bert

Dex Dexter wrote:
> Hey,thanks Bert!That's veeery interesting.Do you know if that corona
> charging effect   happens also in the vicinity of HV power lines?
>
> Dex
>
>
> --- bert.hickman@xxxxxxxxxx wrote:
>
> From: Bert Hickman <bert.hickman@xxxxxxxxxx> To: Tesla Coil Mailing
> List <tesla@xxxxxxxxxx> Cc: Subject: Re: [TCML] My first tesla coil 
> Date: Sun, 06 Sep 2009 14:42:57 -0500
>
> Dex,
>
> In addition to electromagnetic induction, there is also the
> phenomenon of electrostatic induction:
>
> http://en.wikipedia.org/wiki/Electrostatic_induction
>
> Space charges (injected by nearby streamers and leaders) will also 
> induce potentials on nearby isolated conductive objects by direct
> charge deposition via "corona charging". As a result, a sphere,
> placed outside the range of visible discharges from a Tesla Coil,
> will rapidly charge a HV capacitor (where the other end of the
> capacitor is connected to ground). This is markedly different than
> the RF capacitive coupling that also occurs between secondary/toroid
> and nearby conductive objects.
>
> Corona charging or corona rectification has been used to make low 
> current HV rectifiers and is currently used in electrostatic 
> copier/printing and polymer pretreatment for printing.
>
> http://tinyurl.com/kputq5
>
> Bert
>
>
> Dex Dexter wrote:
> > Well,if they remain charged after turning off the coils (for a
> > longer time) that can't be induction.
> >
> > Dex
>
>
>
>
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