A 1 hour lecture as part of their free and open to all series. With the title An Introduction to Teslacoils which included a number of demonstrations.
An audience of 150 people (approx) with ages ranging from 14 up.
EE are actively looking for venues for teslathons in the East Midlands for next year.
Places to hold our events are getting few and far between, mostly because of our “special” requirements.
What is a teslathon : A tesalthon is a meeting of tesla coil enthusiasts. Our tesla coils vary in size from tabletop to 3M tall and are all built by amateurs.
I have been running teslathons for 18+ years and have Risk assessments and method statements to cover the H&S aspects to our hobby.
So what do we need?
The Must have’s
A room with tables a minimum of 11M x 8M in size, on the ground floor that can be blacked out and a ceiling height of ideally more than 4M. Bigger of course is better. We usually have 20 or so coilers and 30-60 visitors to the events.
Plenty of 13A sockets (for our bigger events, a 32A Commando or accessible cooker socket would be needed, or an electrician on site to give support.)
Some method of providing a separate electrical earth. 10 or more tables.
Tea and coffee making facilities 🙂
Other needs (can generally be worked around)
The room needs a minimum (ideally non) of Burglar alarm, Fire alarm or network cables. Electronic lighting can be OK, but they must be high the ceiling. Fire sensors are generally OK, but they must not be of the ionisation type.
Ideal Venues are usually industrial museums or metal skinned warehouses/barns as these have a minimum of electronic equipment. We would like to work with the venues own insurance if possible, but we can provide our own if needed.
I also arrange workshops and talks with lesser requirements, so most venues can be used for something.
We can work in two ways, either a daily rental for the hall, paid by us,or we can work as a ticketed event to raise funds or awareness for a museum, venue or charity.
Before any booking, I would need to assess the venue for safety and suitability.
Have a suitable venue? (Or would like a talk at your venue) contact me firstname.lastname@example.org
Details of past events are here http://www.extremeelectronics.co.uk/cambridge-teslathon/ and here http://www.extremeelectronics.co.uk/nottingham-gaussfest/
Earlier this month it was my great honor to be invited to demonstrate the PI zero tesla coils at the Royal institution Christmas lectures.
The Christmas lectures were a Christmas institution when I was growing up and they formed a great part of my education, especially the ones by Eric Lathwaite. This year is their 80th televised Christmas Lecture, I’m sure in that time it has inspired the lives of many many children to investigate science, and long may it continue to do so.
Behinds the scenes at the lectures was incredible, the organised chaos that was happening was untrue. There were 20+ experiments in the lecture (the first of three) and moving them in and out of the theater was a very well choreographed scientific dance.
I have every admiration to the RI and Windfall Films that produce it.
Walking in to the theater and standing where Faraday and not to forget, Tesla himself had lectured, I can’t explain the feeling. Oh, and the 350+ kids watching you… No Pressure…
The theater is incredible, it’s so much smaller than it looks on TV, add three cameras, a lecturer and 10+ support staff (dressed in black), it doesn’t leave much room for demonstrations that need a couple of meters exclusion zone for safety.
What will be featured on the lecture on Boxing day, not a clue, as is usual with any filming, its down to the final edit.
Even if I don’t make it on to the show, watch anyway well worth it for kids of all ages.
Behind the Ri Christmas Lectures- Show 01, 2016 Mark Parker – Standup Maths (warm up guy)
This Lecture is the first to go out BBC4 20:00 Boxing day 2016
The video is now available at http://richannel.org/christmas-lectures/2016/supercharged-fuelling-the-future
Tesla coils, either classic (with spark gaps) or electronic (with transistors) are impulsive devices. Measuring and comparing power is much more complicated than it initially appears.
With a small electronic coil, the peak current to the primary of the tesla coil can be up to 1MW. This sounds huge, especially for a device that is sitting on your table top and is not engulfed in flames.
But, the answer is simple, the 1MW is only drawn for a very short time and each pulse grows exponentially to this maximum, it isnt constant. In the terms of a small table top electronic coil, the power pulse can last for 100-150uS (1/10000th of a second) and is repeated maybe 500 times per second, during each pulse the current grows exponentially so this gives an average power of roughly 4KW (1Khz – 100uS)
I couldn’t run the coil like this for long without overheating so I allow this for very short periods of time, or if the on time is known to be longer I will limit the output of the coil to that which is sustainable.
As you can see from this, doubling the frequency doubles the power. This explains why the lower frequencies have smaller sparks.
It also explains why I like ‘plonky’ percussive electronic music playing on my tesla coils.
After measuring the weight of my new PiZero Tesla coil project setup, I forgot that one of the tesla coils was still on the scales and applied power. I was very surprised to find that the weight of the running coil varied as the power was applied.
I of course instantly thought there was some electromagnetic effect, so I swapped the expensive scales for a cheap plastic (and staggeringly inaccurate) set. These have no metal parts inside apart from a single spring, so cannot be affected by electromagnetic fields. But they clearly showed the same effect (within an order of magnitude) as the other scale. The table the tesla coil was on was wooden and there was no other electrical equipment near by that could influence the scales.
I made a quick video showing the anti-gravity? effect. Please note that the cheap scales have a huge turn back error, and don’t always return to the correct weight, in fact I think they are pretty much useless even for cooking, never mind a scientific experiment.
After making the video I had more time and so did a much better analysis of the effect.
I checked that the wires were not contributing to the effect, if anything they were producing an additional weight due to their natural springiness, but they didnt move either on their own when put near a powerful magnet. I also checked for any static magnetic fields with an orienteering compass and found nothing over and above the earths natural magnetic field.
After further testing it appears that for every 1.5w RMS of energy put into the tesla coil the tesla coil becomes lighter by roughly 1g. Sometimes the effect isn’t immediate (as the video shows) and can take a second or two to appear or disappear. This hints at the building up of a field? around the device.
Another possible source of the weight change could have been the ion drive (ion wind) effect, well known to any high voltage enthusiast. I have discounted this for two reasons. 1. The effect looses weight in my setup. 2. The scale of the weight change is far in excess of the force of the ion wind from similar powered tesla coils.
I have tried experiments with a simple low power Royer and Slayer circuits and I have not seen the effect. I suspect that the effect only appears at higher powers. (100W+ ?)
Help with research
I would like for this observation to be verified by other tesla coilers. If possible please set up a test with you own coil. Please give an idea of the type of coil, the power in, the initial weight of the coil, any weight change (+ or-ve), details of the weighing system used and any notes regarding the effect. I will list the results and coilers details on this page as a central reference for other experimenters. Please note the safety warning below when making measurements.
Effect with CW and valve coils.
Effect with static gap and rotary coils. (magnifiers?)
Accurate weighing of running high power Fly-back circuits and car ignition coils.
Industrial Inductive heating – reported effects of the molten metal suspended in the working coil, a connected phenomenon ?
Did Tesla know of this effect ?
Probably not, His coils although powerful were very heavy and securely bolted to the floor, it is unlikely he would have noticed the small change in the weight of his devices.
Electric space propulsion – microwave thrusters or quantum vacuum plasma thrusters (QVPT)
There is a lot of similarity with these devices, they both use high voltage and work with large RF fields, maybe there is a connection?
Warning / Safety
As modern tesla coils become smaller, lighter and more powerful, the above effect could have more and more significant effects on these tesla coils. I would strongly suggest that when running any tesla coil they are securely fastened to the ground with a safety chain and the possibility of loose/floating tesla coils should be included in any risk assessment until we know more about this phenomena.
Any questions regarding this effect, or to give your own results for inclusion on this page, please contact email@example.com
As of midday today all of the observed behaviour has stopped and I cannot repeat the findings. I can only assume this was a glitch in the space time continuum that lasted for 12 hours.
It is often said to me that a Tesla Coil produces 1,000,000 V or more.
This is a common misconception. Unless you have an absolutely huge Tesla coil, the actual voltage at the top load is much smaller.
The mistake comes from the widely accepted rule of thumb that the voltage that an electrical discharge will jump determines the voltage present, in normal air at atmospheric pressure this equates to 30Kv per cm . [Paschen’s Law] So it is easy to see that if a tesla coil produces sparks that will jump 30 cm or so, this means that the voltage on the top load must be roughly 1MV.
Unfortunately the situation on a tesla coils top load is a bit more complicated and the 30KV/cm rule does not apply in quite the same way.
The physics of the arc itself needs to be taken into account and the Radio frequency AC that is created. The Tesla coil is effectively a high voltage, high impedance AC current source [Tesla Coil – Output voltage] . So when the spark is being created as the spark grows it forms a capacitor that draws current from the tesla coil reducing the top load voltage. This effect happens as soon as the torroid breakdown voltage has occurred and gets progressively worse as the spark leader forms. This is therefore governed by the voltage breakdown of the minor diameter of the tesla coils top load
The maximal achievable potential is approximately equal to the sphere radius R multiplied by the electric field Emax at which corona discharges begin to form within the surrounding gas. For air at STP the breakdown field is about 30 kV/cm – [https://en.wikipedia.org/wiki/Van_de_Graaff_generator]
So the voltage on the top load of a tesla coil tends to be slightly more than the standoff voltage of it smallest diameter. Vmax = R·Emax (R = Radius, Emax = Breakdown voltage in air 30Kv). For a teslacoil with a 20cm (minor) diameter top load this is around (20cm/2) * 30Kv = 300Kv
But… 300Kv will only give sparks of 10cm according to the 30Kv/cm rule, Tesla coils can easily achieve better than that?
This is where the second aspect of the tesla coils output comes in to play. The voltage on the top load is both AC and Pulsed. Each burst or pulse of Radio Frequency (RF) creates a 10cm long (using the example above) arc leader from the available 300Kv. This heats and ionizes the air, making it conductive this is what you see as the arc in the air.
If very rapidly after the first burst of RF comes another, the channel won’t have had time to dissipate so there is a conductive channel the new pulse can use. The energy rushes to the end of this ionized channel and tries to create another 10cm leader there. Not only does this almost double the spark length, but the energy also re-ionizes the channel. This continues with the third, fourth, n … pulses, each time adding on a slightly diminishing (due to losses) leader to the existing spark.
This continues until something disrupts the channel usually the air rising as it get hot.
This can be easily proved with a modern electronic tesla coil. Set the coil to produce a single burst of RF, this gives a discharge that can be measured using the 30Kv/cm rule and can give a fairly accurate indication of the terminal voltage.
So unless you see a tesla coil with a 66cm minor diameter top load it isn’t producing 1MV
The BIGG coil of Oklahoma, probably the only true 1MV tesla coil.
[shortlink url=”http://tinyurl.com/msd4o8v” title=”Continued From V8 Tesla Engine”]
After playing with the V8 Tesla engine I realised that I could build a stand on tesla coil. The lack of mains power could make this “fairly” safe.
So I started with a topload that was big enough and strong enough to stand on. I started with a pair of 110mm PVC tubes and joined them together. The thought was to make an oval tesla coil (big mistake).
After winding the secondary, by hand (1000T of 0.33mm wire ) on to the former I started to realise that there was a problem, the wire stretched slightly and started to sag between the two tubes. To give the wire some support I wound PVC tape around the coils as I completed them. This was partially successful, but as I had nothing to loose so I continued.
The Topload needed to be strong enough to
stand on too and smooth and an oval.
So I started with an MDF former of 3 oval sheets spaced to a total height of 2.5″, and an external wrap of pipe lagging to give the external shape.
Over this I added paper mache and then a covering of plaster and PVA glue to give it strength. This last layer could be sanded to smooth out the edges.
The output from the V8 tesla engine is fed into a primary cap and an crude sparkgap.
Here is the coil working at the Nottingham Gaussfest.
Note that the problems with the secondary coil are starting to show with a breakout at the bottom.
But it was worth having a go at standing out the coil. After a while I found that the tuning point changed only a single turn when I was standing on the coil.
Below is a video of the first run with me on top.
So the rebuild begins
This time I’ve packed out the space with some cardboard in the void between the PVC pipes and sheets under the coil bridging the two pipes. The cardboard is held in place with many layers of adhesive craft paper that was varnished before the wire was wound on.
The finished article looks a load better then the old one, but there is still some minor ‘droopage’ between turns. So the coil was heavily varnished after winding.
Hopefully it will not suffer the same breakouts as the old.
Also I decided to clean and re-mount the sparkgap the old copper pipe gaps were a little? corroded.
The Sparkgap is mounted on to a channelled acrlyic chamber that allows a high volume fan to blow air over the gaps for cooling and more importantly spark quenching.
Better results from the new coil