If you wire two boards together (wire the two sounders together with a long bell-wire cable, be careful to get them both the same way around) you can make a telegraph system with a button and sounder at each end. Then you can practice sending and receiving for real….
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) http://ntrs.nasa.gov/search.jsp?R=20140006052 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.