Near HV X-Rays; A Question For Senior Members - OTT

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Near HV X-Rays; A Question For Senior Members - OTT

Mark Hanson-2

Hi Cor etc,If >30kv causes nasty X-rays what about those giant Tesla Coils I've built over the years that put out foot+ arcs >100kv?  Or Van De Graff and Whimhurst static arc machines?Best regards,Mark www.REEVA.info From: "Cor van de Water" <[hidden email]>
Subject: Re: [EVDL] A Question for Senior Members - OTT!
To: "Electric Vehicle Discussion List" <[hidden email]>
Message-ID:
<[hidden email]>
Content-Type: text/plain; charset="us-ascii"

Any place that there is current flowing at those
voltages (the leaky insulators that BUZZZZZ when the
air is moist) will indeed emit electrical noise as
well as X-rays.
Typically you are not physically possible to be near
such a source since it is usually not only some
distance away from housing but also some ways up
in the air.
But yeah, they will likely produce a fair share of
nastyness.
Did you ever see a black rubber ignition cap that had
leakage or a broken wire (spark gap)?
That black rubber has turned white inside and not from
the deposits, but it is bleached white. Nasty stuff.
(BTW, this has nothing to do with X-rays but with the
excessive UV from sparks, the same reason you should not
look directly at an electric welder)

Regards,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [hidden email] Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On
Behalf Of Martin WINLOW
Sent: Sunday, August 26, 2012 12:49 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] A Question for Senior Members - OTT!

Er... do you mean to say that every over-head power transmission line
(typically 30kV - 120kV) is pumping out 'hard' X-rays? Wouldn't these
be quietly frying the people unfortunate enough to be living beneath
them?

MW
     
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Re: Near HV X-Rays; A Question For Senior Members - OTT

Jeffrey Jenkins
Mark Hanson-2 wrote
Hi Cor etc,If >30kv causes nasty X-rays what about those giant Tesla Coils I've built over the years that put out foot+ arcs >100kv?  Or Van De Graff and Whimhurst static arc machines?Best regards,Mark www.REEVA.info
In order to produce X-rays the electrons emitted from the cathode need to be accelerated to extremely high speeds (close to c) before striking the anode. Air molecules get in the way of the electrons which is why HV sources in the atmosphere don't produce x-rays; they do, however, produce corona, and THAT is what discolors the rubber around spark plug boots, etc.


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Re: Near HV X-Rays; A Question For Senior Members - OTT

Dennis Miles
You-all have it all right, Voltages in excess of 32KV used in large screen
CRT displays (Like 28 to 36 inch Cathode Ray Tube TV picture tubes begin
producing "Soft X-Rays" but the thick glass front on such displays absorb
the "X-Rays " to make viewing them from five feet or more safe. 40 years
ago when that was my business we warned customers not to let the family pet
stay under the console TV as that may contribute to Cancer for their pet ,
I suggested a basket of artificial flowers to persuade the cat to
cat-nap elsewhere. Also for most 27 inch and smaller TV we set the
HighVoltage to 27KV  max to make it safer, we wanted the repeat business of
our customers and weren't trying to sent them into the hospital... (I
attended Factory Training for Advent "Big Screen TV" and the instructor
included that statement above about keeping customers.) That all said
concerning EV, the Pacl power wiring to the Motor control and to the motor
too, Skould be in orange metal conduit filling that conduit less than 50%
in cross sectional volume, and twisted three twists per foot from end to
end. also the orange conduit must be grounded at the motor controller end.
(I use flexible exhaust pipe, it is easy to bend to follow the bottom of
the vehicle, paint with a "Rattle Can" international orange color, cut to
length with a hack saw, and i place a tight fitting six inch length of
radiator hose into each end with some glue on the inside of the metal and
the outside of the length of hose to prevent the edge of the cut pipe from
damaging the two wires in the pipe. DO NOT put any other wiring in the same
pipe as the Pack wires. Finally twist the two wires to the Motor from the
motor controller together at the three turns per foot also holding them
together with nylon cable-ties (Not metal !) Then cover the wires (All but
the last 3 inches of each end with orange electrical tape, -two layers
minimum-) And use preformed insulating covers on all terminals so no bare
metal is exposed. Of course we expect you will use insulation covered tools
always ! as well as Welders gloves and insulating thinner gloves on your
hands inside the welder's gloves. And full face shield may save your eyes
or beautiful complexion from burns or wounds if the wring items touch even
for a fraction of a second. Remember to "Practice Safety," it is far less
expensive than wound care and plastic surgery.

On Fri, Aug 31, 2012 at 8:08 AM, Jeffrey Jenkins
<[hidden email]>wrote:

>
> Mark Hanson-2 wrote
> >
> > Hi Cor etc,If >30kv causes nasty X-rays what about those giant Tesla
> Coils
> > I've built over the years that put out foot+ arcs >100kv?  Or Van De
> Graff
> > and Whimhurst static arc machines?Best regards,Mark www.REEVA.info
> >
>
> In order to produce X-rays the electrons emitted from the cathode need to
> be
> accelerated to extremely high speeds (close to c) before striking the
> anode.
> Air molecules get in the way of the electrons which is why HV sources in
> the
> atmosphere don't produce x-rays; they do, however, produce corona, and THAT
> is what discolors the rubber around spark plug boots, etc.
>
>
>
>
>
>
> --
> View this message in context:
> http://electric-vehicle-discussion-list.413529.n4.nabble.com/Near-HV-X-Rays-A-Question-For-Senior-Members-OTT-tp4657611p4657639.html
> Sent from the Electric Vehicle Discussion List mailing list archive at
> Nabble.com.
>
> _______________________________________________
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--
Regards,
*Dennis Lee Miles*   (863)944-9913 (call noon to midnight Eastern time)
*[hidden email]*
*+++++++++++++++++++++++++++++++++++++++++*
*Offering a 12 day class Sept. 10 to 22, 2012 *
*in Central Florida. more info on Web;
WWW.ElectricVehicleTechnicalinstitute.COM<http://www.electricvehicletechnicalinstitute.com/>
*
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