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Registered Member #4266
Joined: Fri Dec 16 2011, 03:15AM
Location:
Posts: 874
What materials for the work bench. For light fixture do I need to keep the arc length *2 away. I've reached 100kv And i'm still alive :(, but wood has surface arcs
Wood becomes conductive as frequency increases, so if your HV is also HF you need to switch to something other than wood for insulation. Delrin, PVC, acryllic, porcelain, glass, and polypropylene are all excellent insulators at higher frequencies.
The general rule of thumb is for every 1mm you need 1kV to break down the air in between two rounded surfaces. Sharp surfaces have higher charge densities and require lower voltages to break down across the same distance.
So for a HV lab you need adequate and ample grounding, adequate and ample insulators, and adequate and ample space between you, anyone else, and anything sensitive and the source of the HV. Safety power disconnects and bleeder resistors across any capacitive element are not optional.
The most important aspect is maintaining absolute rigidity of safety precautions and standards. Never touch ANYTHING without checking over and over again that all power is off and everything is discharged.
Registered Member #834
Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644
Voltage is not dangerous. Energy is. You can safely play with a 200 kV Van de Graaff generator, but if you draw a spark from a 10 kV power line you die. Note that most of the 100's of kV devices mentioned in the Internet, including this forum, don't actually go above 25 kV, that is easy to "contain" without much care. At 50 kV you have corona everywhere, and all the installation must have rounded corners and ends, and long insulators. At 100 kV these precautions must be more than doubled. Use at least 1 cm of radius for each 30 kV for spheres and rounded ends. Less can be used for straight connections. Basic safety measures are, obviously, never touch a high-voltage low-impedance device while it is working, and specially never touch it with both hands. For insulation, never use wood, paper, or similar materials (although they may work if saturated with a good insulator as paraffin or other waxes).
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Houdini0118 wrote ...
Death and explosions come to mind.
Yes, I too imagine these "issues"
First, and above all, Distance is the best defense against any human safety and health threat. (if a nuclear weapon goes off on the moon, no big deal. If a hand grenade is thrown into a locked phone booth, your screwed.)
then, and much less effective, there is armor, shielding and insulation.
finally, theres a bunch of fiber optic and other safety features that can be implemented.
Registered Member #4266
Joined: Fri Dec 16 2011, 03:15AM
Location:
Posts: 874
Note that most of the 100's of kV devices mentioned in the Internet, including this forum, don't actually go above 25 kV, that is easy to "contain" without much care. At 50 kV you have corona everywhere, and all the installation must have rounded corners and ends, and long insulators. At 100 kV these precautions must be more than doubled. Use at least 1 cm of radius for each 30 kV for spheres and rounded ends.
How would you go about stopping corona from the wires that interconnect things
What type of experiments would you be conducting at those voltages?
Trying to experiment with arcs and plasma. Was planning on making a voltage doubler with 20 stages with 15Kv input to get a longer distance at the moment its only 4cm.
Wood becomes conductive as frequency increases, so if your HV is also HF you need to switch to something other than wood for insulation. Delrin, PVC, acryllic, porcelain, glass, and polypropylene are all excellent insulators at higher frequencies.
If I had a Faraday cage around the doubler and arc, with it grounded with its own line to outside and be in a different room, by the sounds of it should be ok. I've got a wood work bench need to find some of those materials to coat it with.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Take this as a Golden Rule: if you must make adjustments to a live circuit of anything more than 100 V or so - for example, when setting up RF circuits using thermionic valves - you must always keep one hand in your pocket at all times, so you cannot get an across-the-body shock - which is the most lethal kind.
Arcs and plasmas can be produced with a few kV and less. No need for hundreds of kV at all to do very interesting experiments along these lines.
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