Generally I would say that if you use wire with a rated voltage with some head room, there is no special precations, except at where the wire is mounted, you will need bigger distances and isolation.
1kV double isolated wire is common and can be found from anyone building or supplying for electrical control panel construction.
1kV is still low enough to be of little concern in my opponion regarding coupling between wires, at 4kV I have noticed capacative coupling between wires affecting performance.
Give a good 10 mm distance to anything and you are on your way. Avoid materials near that contains carbon as high voltage easily can creep/burn along a carbon track, even over long distances.
If you really want to be sure, keep all surfaces conducting the high voltage round, sharp edges are known as break out point and at higher voltages can result in corona losses. Epoxy or varnish everything soldered for higher isolation.
You could also incapsulate the wires in clear tubing, fill it with oil, but this is way over the top for a mere 1kV.
A good and cheap source for high voltage wire, old TV sets, there you can salvage some 50 cm per set of 10-15kV rated wire.
I hope these experiences from a high voltage amateur can be of help
1kV double isolated wire is common and can be found from anyone building or supplying for electrical control panel construction.
1kV is still low enough to be of little concern in my opponion regarding coupling between wires, at 4kV I have noticed capacative coupling between wires affecting performance.
Give a good 10 mm distance to anything and you are on your way. Avoid materials near that contains carbon as high voltage easily can creep/burn along a carbon track, even over long distances.
If you really want to be sure, keep all surfaces conducting the high voltage round, sharp edges are known as break out point and at higher voltages can result in corona losses. Epoxy or varnish everything soldered for higher isolation.
You could also incapsulate the wires in clear tubing, fill it with oil, but this is way over the top for a mere 1kV.
A good and cheap source for high voltage wire, old TV sets, there you can salvage some 50 cm per set of 10-15kV rated wire.
I hope these experiences from a high voltage amateur can be of help
There is around a hundred titles online here, old scanned radio books, should be just what you are looking for.
Technical books online
Hi Bas,
I always use double insulation for such high voltages. I pull an extra sleeve over the wire. Make sure no high voltage carrying wire gets clamped anywhere in the chassis or nicked or insulation accidentally burned with the soldering iron.
For 1kV keep 1cm distance between bare metal. Note that the plate of the output tube can swing up to twice the B+. So extra care is needed there. Mount the tube sockets such that enough creeping distance is ensured.
Ensure all parts have the proper voltage rating not only the caps (they should have ample headroom) but also chokes and resistors. Use several resistors in series for bleeder.
The heater winding of a rectifier tube will carry high voltage. Make sure the transformer has the proper insulation rating.
If the PSU operates without load it's output voltage can rise significantly. All caps should be rated to cover that case. A well sized bleeder will avoid a big voltage rise if the PSU is unloaded.
Best regards
Thomas
I always use double insulation for such high voltages. I pull an extra sleeve over the wire. Make sure no high voltage carrying wire gets clamped anywhere in the chassis or nicked or insulation accidentally burned with the soldering iron.
For 1kV keep 1cm distance between bare metal. Note that the plate of the output tube can swing up to twice the B+. So extra care is needed there. Mount the tube sockets such that enough creeping distance is ensured.
Ensure all parts have the proper voltage rating not only the caps (they should have ample headroom) but also chokes and resistors. Use several resistors in series for bleeder.
The heater winding of a rectifier tube will carry high voltage. Make sure the transformer has the proper insulation rating.
If the PSU operates without load it's output voltage can rise significantly. All caps should be rated to cover that case. A well sized bleeder will avoid a big voltage rise if the PSU is unloaded.
Best regards
Thomas
Hi Bas,
First things that came to mind were
:813 SE triode amps
WD8DAS Homebrew Transmitter Page
http://web.archive.org/web/20030114113629/http://www.arrl.org/news/features/2002/12/27/1/
If you're doing web searches, keywords - transmitter (as opposed to radio), homebrew, corona etc. will get you more.
First things that came to mind were
:813 SE triode amps
WD8DAS Homebrew Transmitter Page
http://web.archive.org/web/20030114113629/http://www.arrl.org/news/features/2002/12/27/1/
If you're doing web searches, keywords - transmitter (as opposed to radio), homebrew, corona etc. will get you more.
I've used MG Chemicals brush-on conformal coating. 1500V per mil (1/1000th of an inch) dielectric strength. Comes in three varieties, acrylic (fast dry, reworkable, solderable), urethane (physically tougher), and silicone (more flexible). There's also a product called Corona Dope that is even higher, but I haven't used it myself.
An externally hosted image should be here but it was not working when we last tested it.
When using pcb mount fuses buy the ones that get transparent covers that clip on to prevent accidental shock.
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I wouldn't rely on Teflon wire without some care - pure Teflon creeps forever - so any pressure point will thin the insulation over time
and the common Ag plated stranded wire wicks solder like crazy - rendering the wire essentially solid near the joint - add a nick from stripping without the recommended thermal stripper (the fumes will kill your canary) and you are likely to get stress concentration joint failure - complete break with only slight flexing, or low level vibration
so Teflon insulated wire requires thermal stripping, careful fixing near the joint, mechanical buffer from any edge with sleeving, grommets...
and the common Ag plated stranded wire wicks solder like crazy - rendering the wire essentially solid near the joint - add a nick from stripping without the recommended thermal stripper (the fumes will kill your canary) and you are likely to get stress concentration joint failure - complete break with only slight flexing, or low level vibration
so Teflon insulated wire requires thermal stripping, careful fixing near the joint, mechanical buffer from any edge with sleeving, grommets...
Think about power-up and power-down conditions. It's easier to get into trouble with higher voltages... like if B+ comes on before a tube is fully heated, it may get it's Vao maximum cold voltage exceeded, and arc. Also inrush currents, and what happens if something gets shorted, become more of a concern at HV.
Also keep in mind energy stored in a capacitor is 0.5 * C * V^2... high voltage on a big capacitor presents an energy hazard. Shorting a 40uF cap charged to 300V makes a loud pop... try it at 1kV and you get a frightening bang and some welding!
I've never had any issues with insulation. Air breaks down around 3kV/mm... creepage distances along insulators like terminal strips or PCBs are more of a concern.
Also keep in mind energy stored in a capacitor is 0.5 * C * V^2... high voltage on a big capacitor presents an energy hazard. Shorting a 40uF cap charged to 300V makes a loud pop... try it at 1kV and you get a frightening bang and some welding!
I've never had any issues with insulation. Air breaks down around 3kV/mm... creepage distances along insulators like terminal strips or PCBs are more of a concern.
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