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Contactless Electrical Current Transfer?

Posted by Cliff on from the keep-your-hands-and-feet-away dept.

ferralis (Not an EE) asks: "Recently I've come up with a design for a very fun toy (to be unveiled later if I'm successful). What's missing is a means to send electrical power over a distance of five to ten centimeters (2-4 inches). I've done some research (mostly online) and have found extremely limited information. Even my beloved Google has forsaken me, and even my pleadings to eldritch information deities such as AltaVista have gone unrewarded. Can anyone help?" "The way I see it, to do this a person needs merely set up a high-frequency electrical field using a larger coil (primary) and a similar but smaller coil (secondary) can be placed within it, creating an air-core transformer. Unfortunately I can't find the math or even anecdotes about what happens when the secondary is off-center, or there is more than one secondary introduced... and I am not looking to build a Tesla coil here. I can imagine that many toys could be built using such a system, and one would think the knowledge would be well known and readily available, but apparently it is not. For this application, efficiency is -not- an issue."

2 of 73 comments (clear)

  1. Re:The coil thing should work. by eclectro · · Score: 2, Insightful

    I have a shaver that does this too, it sits in holder and charges.

    However he says he needs to do it over a distance of 2 to 4 inches, and there won't be enough coupling between the coils to achieve enough voltage to charge the battery.

    I'm not saying that it is impossible, but rather exotic electronics means expensive electronics, and most toys are very price sensitive.

    Anyway, that was Tesla's great dream, to transmit power.

    --
    Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
  2. Details? by JGski · · Score: 3, Insightful
    Hmmm.

    Unfortunately this is one of those questions like you get on sci.electronics.* which doesn't include the basics like how much power is required; at what voltage and current levels, AC or DC, what frequency, can "it" run unconnected (e.g. on battery) and if so for how long (application-wise, not technology-wise), etc. etc.

    Barring nice engineer-friendly technical specs, at least outline more specifically what you're trying to do, at least in vague terms, would be more helpful. Starting out by saying it's a product idea (rather than just some hobby thing) was probably mistake if you're paranoid about competitors.

    Without some minimal specifications of this sort, absolutely any answer you get will either be hopelessly vague, utterly useless or simply a troll.