A Big Transformer, Because It’s Cool!

[Grenadier] Had some spare wire, electrical tape, and a giant ferrite core laying about and decided to create a massive and pretty snappy looking disk shaped flyback transformer. Dubbed the Fryback, he claims that it will “revitalise your health and bring wondrous wealth and prosperity to your family”.

He chose a disk shaped transformer because they look cooler, fair enough.. (oh and they reduced inter-winding capacitance and the voltage difference between layers). The construction is fairly simple, but time consuming. Grenadier goes through the important steps on his website, but be prepared for 25 hours of winding wire if you decide to make your own.

Running at 48V the Fryback can output 8kV at a very high current, producing some nice thick 30cm long sparks. Check out the video after the break to see the Fryback in action.


29 thoughts on “A Big Transformer, Because It’s Cool!

  1. 48VDC might produce a mild tingle on dry skin. But get it wet or penetrate the skin and with that much current behind it… *could* be a problem.

    Depends on the path to ground, amperage, type of current, etc.

    But it is running at 48V. It produces 8,000 volts at “a very high current”. A high current is meaningless if the voltage is so low that it can’t penetrate (unbroken, dry) skin. But that’s not what we are making here.

    Also, there have got to be ways of winding this using some kind of mechanical advantage, even if you have to spend 3 or 4 hours building a bobbin winder mechanism or some such.

  2. For what it is worth, recent NEC code does talk about “high” voltage DC current and even allows “low” voltage DC current (even at thousands of amps) to be used in literally bare metal bus bars. I believe the threshold is 50 or 75 VDC. Anything under that is considered “low” voltage in bus bar application – even if you have thousands of amps of current.

  3. “producing some nice thick 30cm long sparks”
    This is misleading. A 8kV flyback is only capable of producing a spark through a couple of centimeters of air. In the video he can only go to 30cm due to the breakdown of air into plasma which is better conductor. Try doing the same horizontally and you will get a nice jacob’s ladder.

  4. ooooohhh that looks just like a plasma torch.

    How warm/hot do the wires get on the primary side? They look a little thin …

    Spark, yes, for the ignition, which then transforms into (plasma) arc.

    I now see the rubber chicken! tres nifty :)

  5. @hackerspace

    The NEC doesn’t actually define Low Voltage, only High Voltage as being >600V.

    Interestingly enough they are missing a definition since <60VDC according to DIN, IEC, BS, and AS would actually be Extra-Low Voltage.

    Also IEC rates maximum safe touch potential as 50VDC.

  6. Just spoke to someone today about the new hybrid gas fired boilers being built which also double as a grid tied inverter.

    It seems that in order for the magnets not to degrade with heat they use a variant of the AC induction generator that runs on high frequency AC instead, taking advantage of skin effects.

    High voltage low current at many hundred kHz = small device which fits into something not much bigger than a conventional CH pump yet can comfortably generate a couple of kilowatts of power when driven at several tens of KRPM.

    The other variant was a thermoelectric generator which takes the waste heat from the gas burner and uses a countercurrent multiplier to get a large enough temperature differential to generate power.
    Makes more sense to “dump” the excess heat as electricity rather than mixing with cold water methinks.

    The same tech is being used on the newest electric cars to avoid using rare metals in the magnets; silver coated enamelled copper wire stator and rotor is the “secret sauce” here as its surface conductivity is better than copper at HF.

  7. Reminds me of the time my college roommate and I build spark generator out of a 3vac power supply and the flyback from an old B&W TV. Was supposed to be safe enough that a person could touch it.

    However, my dumbass roommate decided to substitute some parts without telling me, particularly the 12vac power supply and the flyback from a color TV. I eventually regained the use of my arm. :(

  8. re: 48VDC… I work with the stuff all the time in the IT/telco world… I’m much more worried about dropping a tool across the terminals (thus blowing up some expensive glass-encased lead-acid batteries, as well as melting said tool) than actually touching the terminals with my bare hands…

  9. @ Steve Shockley

    Lol, that’s something I would say, however it wouldn’t exactly be a ladder if the rungs were removed and it was split open like a pair of woman’s legs.

    @ Asheets

    I agree, I’d be more worried about the lead acid batteries (I take it you’re working with backup power supplies in the termination buildings?). I HAVE dropped a wrench between the terminals on my tractor battery once, needless to say I was scrambling around for something to smash it out from the terminals quickly! Thank god it was already nearly toast and didn’t have a good charge in it.

    I’ve also often wondered if I were to short out the terminals of the POTS termination box on the outside my house, if my telephone company would just have some kind of temporary fuse on my telephone line, kind of like if you short out a usb port, just shut off the computer for a while and it resets. Or would you blow the POTS splitter card up the street in the termination building?

    This is something I’ve wondered for a long time, also too, anyone here held onto the wires outside their house and have someone call? I have, try it sometime. No really, try it :P Cursing and swearing will ensue.

  10. Does anybody else notice that this could have been even *better*?
    In the opening they note that they cracked the core, but repaired it ‘good as new’ with some super glue. According to my understanding of transformers though, the continuity of the magnetic flux will now have an extra break in it, changing the shape of the field overall. This would result in a loss in performance, though someone else would have to do the math on that.

  11. Probably due to the video angle, but at around 1:15 to the end, It looks like (i believe) the transformer in the back is smoking up. but that could be the razor or (what i think it is), the quarter that could be the cause of the smoke.

    I am not very knowledgable on this subject, but i very much like the fact that you can make (once again what i think it looks like) a plasma arc outside a vaccume tube.

    and aside from all that i dont know about transformers and arcs, i wonder how much “fun” you would have trying to swipe your hand or fingers BETWEEN the arc. im sure its just like touching both ends, but again, not that smart upon this particular subject.

  12. I worked in the UK telecoms industry in the 1970s and the electro-mechanical telephone exchanges then used 50 VDC for main power ‘because it was safe’. True, I rarely had a shock from the equipment unless a sizeable relay was powered down by my taper-nosed pliers (81s ?) clearing a fault. In the hot summer of 1976 when the temperature in the exchange reached 32 deg C you could get quite a belt (probably several hundred volts) from the back emf in the relay coil. I’ve also seen a pair of pliers, accidently rested across the two busbars at the top of the equipment frame glow white hot and start to shower sparks before they were violently kicked off.

    The power used to ring the telephone bell when a call is received was 50 VAC. This was called ‘ringing current’, and could give quite a belt too as it was AC. AC was used because, for reasons of reliability, the solenoid-armature-bell setup in the phone didn’t have a breaker to interrupt the supply as a buzzer does.

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