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Re: Impedance of Corona or Arcs vs Voltage (fwd)
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To: tesla@pupman.com
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Subject: Re: Impedance of Corona or Arcs vs Voltage (fwd)
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From: Tesla List <mod1@pupman.com>
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Date: Wed, 15 Jul 1998 22:05:59 -0600 (MDT)
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Approved: mod1@pupman.com
---------- Forwarded message ----------
Date: Wed, 15 Jul 1998 21:33:27 -0700
From: "Antonio Carlos M. de Queiroz" <acmq@compuland.com.br>
To: Tesla List <tesla@pupman.com>
Subject: Re: Impedance of Corona or Arcs vs Voltage (fwd)
Jim Lux wrote:
> The corona onset voltage (for AC) is roughly where the E field strength
> gets over 30 kV/cm. This is mostly determined by the radius of
> curvature. If the radius of your "thing" is 1 cm, then when it reaches
> 30 kV, corona will start. The presence of nearby conductors will
> definitely affect the E field distribution, and hence, the corona onset
> voltage.
The rule about the 1 cm of radius for each 30 kV is correct for a polished sphere,
or a surface curved in all directions, for peak voltage values, including DC.
Do you know what is the rule for a long cylindric conductor, as a high-voltage
cable? It is not this, as 500 kV power line cables don't appear to have 47 cm
of diameter (500*1.4142/30*2).
(too lazy to make the derivation)
Antonio Carlos M. de Queiroz