[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] My first tesla coil

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






_____________________________________________________________ 
Washington DC's Largest FREE Email service. --->

http://www.DCemail.com ---> A Washington Online Community Member --->

 http://www.DCpages.com 
_______________________________________________ Tesla mailing list 
Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla