File talk:Erdungswiderstand Zwei Halbkugeln.svg
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When inspector comes, he put one wire to existing electrodes and two electrodes on 50 and 70 meters from existing electrodes. Circuit electrodes -> 70 meters measures amperage, circuit electrodes -> 50 meters measures voltage, then his tester will show resistance of earthing. Here is coverage area of electrodes is shifted from center to the edge. More about ground resistance can be founded here. Dmitry G (talk) 08:01, 19 May 2011 (UTC)
- This drawing is only a very simple sketch to illustrate the simple case on how to calculate resistance of earthing - And to demonstrate that this resistance is related mainly to the electrical conductivity on the soil nearby the electrode and to the appearance (geometry) of the electrode with radius r. r must be much less than d. This simplification is not very realistic - It's useable for a simple calculation only.--Wdwd (talk) 18:47, 20 May 2011 (UTC)
- Hemispheres are drawn not understandable way; when I saw hemispheres first time, I've thought about coverage with missing electrodes. Only translation from German language shed me the light, that "r" are hemispheres =) But in real life earthing device might be hammered into the ground even to 40-50 meters depth, so you can increase only distance (d) between them, but reducing their dimensions (r) is forbidden. Dmitry G (talk) 20:38, 20 May 2011 (UTC)
- Yes, correct. The hemisphere has the advantage for an easy (analytical) calculation, in basic lectures. Not for practical reason in real life - i believe, nobody will build an earthing system with hemispheres :)
- I put your earthing sketch in the german article. To illustrate practical measurements.--Wdwd (talk) 17:41, 21 May 2011 (UTC)
- Thanks for putting my sketch to article! I meant about color of hemispheres - they are yellow, which is not associated with metal. Grey color would be better. I've understood that it is metal hemispheres only after reading comment on german wikipedia; yellow color put think that it is electrode's coverage. Commonly metal is grey, not yellow. Dmitry G (talk) 18:24, 21 May 2011 (UTC)
- I change the color to grey. At the moment we have some technical issues on commons with the image caching, so update will take a little bit longer.--Wdwd (talk) 18:09, 22 May 2011 (UTC)
- Yes, grey is more better for metal objects. Dmitry G (talk) 20:36, 22 May 2011 (UTC)
- I change the color to grey. At the moment we have some technical issues on commons with the image caching, so update will take a little bit longer.--Wdwd (talk) 18:09, 22 May 2011 (UTC)
- Thanks for putting my sketch to article! I meant about color of hemispheres - they are yellow, which is not associated with metal. Grey color would be better. I've understood that it is metal hemispheres only after reading comment on german wikipedia; yellow color put think that it is electrode's coverage. Commonly metal is grey, not yellow. Dmitry G (talk) 18:24, 21 May 2011 (UTC)
- Hemispheres are drawn not understandable way; when I saw hemispheres first time, I've thought about coverage with missing electrodes. Only translation from German language shed me the light, that "r" are hemispheres =) But in real life earthing device might be hammered into the ground even to 40-50 meters depth, so you can increase only distance (d) between them, but reducing their dimensions (r) is forbidden. Dmitry G (talk) 20:38, 20 May 2011 (UTC)
