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Registered Member #530
Joined: Sat Feb 17 2007, 07:56AM
Location: Victoria BC, Canada
Posts: 178
Well, I am happy to announce that the school I work for has given the green light for an "advanced" educational project involving an elite group of students. I'm pumped! Really! Naturally the power supply unit will be locked out as it is a dual PT set run in parallel for 6-7 kW. I'll send photos when I get my camera battery recharged.... and hopefully I can do a test at 1600 watts tonight using my NST bank. ....might have to go with a slightly lower power NST due to the breaker tripping! I have a 12kV 100 mA unit that should do the trick... If this happens I'll be uploading some video to the website... I hope you don't mind ;)
So I did a quick calculation of the inducatance -secondary - 87.7 mH (30" wound with 27 AWG) -Primary - turn 4 tap = 6.7 uH (1/2" tubing - 12 turns total with an 2.2" spacing) -coupling coefficent = .112
Registered Member #530
Joined: Sat Feb 17 2007, 07:56AM
Location: Victoria BC, Canada
Posts: 178
Tesla Coil got fired up today using a 12kV 100mA NST w/ .032 uF cap. Okay I wasn't using much of a topload but the coil did produce some decent sized sparks from only having number 10 turn tapped...
Enjoy the video: ]1186897277_530_FT29693_dscn0841.avi[/file]
Registered Member #530
Joined: Sat Feb 17 2007, 07:56AM
Location: Victoria BC, Canada
Posts: 178
sorry about the double posts
UPDATE Here is a movie + photo of a 56" strike from a doorknob topload while the primary was tapped at turn 12 using the same NST bank as above (1.2kVA). ]1186937310_530_FT29693_dscn0477a.avi[/file]
Registered Member #10
Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424
Not wishing to rain on your parade or whatever expression you use in Canada, but have you considered liability issues?
I personally would be unwilling to do this sort of HV project with noobs, elite or not. The potential for disaster is low but consequences potentially catastrophic. You must at a minimum, notify the student's parents and your school liability insurers and get written assurance from all of them that they will be involved with open unprotected high voltage of high lethality run by non-electricians. It needs to be clearly spelled out including the risk of death with contact. Even then, that will be unlikely to cover your liability. When I do a medical procedure, I need to warn of all reasonable complications including death. I would be surprised if expectations are different in Canada.
I don't risk my children in more than a peripheral role in my HV projects. It only takes one mistake and I certainly would not want them involved with dual PT powered coils at school. Locked out or not. You will find, I think that you will be also contravening electrical codes, noise, RF emission standards etc.
I suggest you reconsider and aim for a safe but equally educational battery powered small coil or similar. Sounds tough but little different to getting kids to use high explosives under supervision, locked out or not. I think parents might understand that better and veto it.
Registered Member #639
Joined: Wed Apr 11 2007, 09:09PM
Location: The Netherlands, Herkenbosch
Posts: 512
For my tesla coil project for school I needed a way to make sure that nothing could happen, otherwise the school refused to give me permission for it. My drsstc will be checked for lacking safety features by the technical university of Eindhoven. It will also be tested there in a giant faraday cage within this cage are cells made of grounded fences. When you open a cell the power will be cut automatically. I also have the help of a high voltage engineer at my school for more direct help.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I just assumed he meant university or college. Americans (and Canadians) seem to call everything "school" whether it's kindergarten or a PhD program. I agree that project may well be unsuitable for a high school.
I've done HV demos to high school students (although I used the Faraday cage facilities at my local university to do it, as part of their open day) and helped to design public Tesla coil installations in Faraday cages that passed European EMC testing. If you are careful, and have someone on your team who knows what they're doing, it's all reasonably safe.
Registered Member #530
Joined: Sat Feb 17 2007, 07:56AM
Location: Victoria BC, Canada
Posts: 178
Tesladownunder wrote ...
Not wishing to rain on your parade or whatever expression you use in Canada, but have you considered liability issues?
I personally would be unwilling to do this sort of HV project with noobs, elite or not. The potential for disaster is low but consequences potentially catastrophic. You must at a minimum, notify the student's parents and your school liability insurers and get written assurance from all of them that they will be involved with open unprotected high voltage of high lethality run by non-electricians. It needs to be clearly spelled out including the risk of death with contact. Even then, that will be unlikely to cover your liability. When I do a medical procedure, I need to warn of all reasonable complications including death. I would be surprised if expectations are different in Canada.
I don't risk my children in more than a peripheral role in my HV projects. It only takes one mistake and I certainly would not want them involved with dual PT powered coils at school. Locked out or not. You will find, I think that you will be also contravening electrical codes, noise, RF emission standards etc.
I suggest you reconsider and aim for a safe but equally educational battery powered small coil or similar. Sounds tough but little different to getting kids to use high explosives under supervision, locked out or not. I think parents might understand that better and veto it.
TDU
We do have insurance for large scale projects for our school. I checked with the admin before proceeding with this project and they agreed to it. The power supply right now is a single PT running 3.5 kW. It will stay that way due to power/safety concerns. I explained that my students will be involved in the construction aspect of the coil ONLY. No student will be in contact with the primary circuit (transformer - switches - etc etc) what so ever ON or OFF! Students will be at a VERY good distance away. Parents will be notified and contacted directly myself for those interested in this project.
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6" Tesla Coil school project
