DC voltage is just as, if not more, dangerous to the human body as AC. You wouldn't want to hook your jumper cables to your car battery and then grab the other ends... As I once heard, AC gives you 60 chances per second (in the US, 50 in many other places) to let go. DC gives you zero. I'm now speaking beyond my actual knowledge level, but amperage, (or amperage plus voltage(?)) determines the intensity of the effect on the recipient body/center pin. Paul Bruesch Stillwater, MN On Thu, Mar 4, 2010 at 8:06 AM, Ken & Pat Gerler <kenneth.gerler at prodigy.net > wrote: > Mike, > I will make a clarification. A Transformer's primary job is to reduce the > AC voltage from what is supplied it, like the electric company's supply to > the building, to a usable AC voltage, 12 to 18 volts for a doorbell use. It > is "Still" AC. It takes a rectifier circuit to "change" it to DC. A > rectifier shunts one side of the pulse of the AC. > > Think of a roller coaster. The "up and down" is what AC looks like. DC > looks like a frog/grasshopper/cricket jumping and then walking the same > distance as it jumped before doing the same thing all over again. > > If I had actual diagrams handy, I would attach them. > > Ken G > > > ----- Original Message ----- > *From:* Michael Magness <ifixpiano at gmail.com> > *To:* pianotech at ptg.org > *Sent:* Wednesday, March 03, 2010 6:45 PM > *Subject:* Re: [pianotech] Center Pin Zapper > > > > On Wed, Mar 3, 2010 at 12:51 PM, Poppy Miles <poppyspys at yahoo.com> wrote: > >> Hi, >> I have been thinking about making a zapper myself, but your email is >> discouraging. There was a zapper at a shop I worked at in Boston that >> seemed to work quite well. It was made by an engineering student for a >> rebuilder there. I'm wondering if this is the same thing as the doorbell >> zapper. I certainly don't want to use a tool on any piano that will damage >> it! I hope that this tool will send a low enough voltage through the pin to >> slowly iron the bushing. When I used it, it seemed to do just that, and I >> was able to get 4-6 swings. Please look over my instructions, and let me >> know if it is similar to what you have built. >> Thank you, >> Poppy Miles,rpt >> >> components: >> Transformer - 6.3 volt @ 10 amps >> Resistors - 0.25 ohm @ 15 watts or more >> Beeper - 4.5 volt beeper >> >> >> 1) A screw terminal you can just screw down on the wire. >> 2) To a lug you connect a wire and solder it. >> 3) Two wires you twist together and solder. >> >> Wires to your probe should be of heavy electric cord, as heavy as you'd >> find on a toaster or blow-dryer. Look for it in a hardware store electrical >> section, where they will have it on reels. >> >> Power In >> 1) Connect one side of power cord to one "PRI" lug of transformer (or >> wire, if it has those instead) >> 2) Connect other side of power cord to other "PRI" lug (or wire) of >> transformer >> >> Power Out >> 3) Make a chain of the three resistors by their wires, so the current >> flows through them all, one by one. >> 4) Connect a wire to one "SEC" lug (or wire) of transformer and run it all >> the way to one of the probes. >> 5) Connect the wire of the first resistor to other "SEC" lug (or wire) of >> transformer. >> 6) Connect a third wire to the connection you just made, and run it to one >> of the two lugs or wires on the beeper. >> 7) Connect a wire to the end of the third resistor and run it to your >> other probe. >> 8) Connect a third wire to the connection you just made, and run it to the >> other lug or wire on the beeper. >> >> >> >> ------------------------------ >> Hi Poppy, >> > > It sounds like a very (unnecessarily)complicated version of what I > described. Why one would need such heavy duty wire or the resistors is > beyond me. > I have an old house that actually uses one of these for the purpose > intended. It is wired into a circuit using 14GA wire(similar to that of a > lamp wire & plug) and the wire running from it to the doorbell is about > 18GA, slightly thicker than the wire that runs from my garage door button to > the opener. > > The whole point of the transformer is to "transform" AC current to DC > current which is much less dangerous to the human body. > Most of us have at one time or another had a little zap from a DC circuit, > as long as the AMPERAGE is low, which most doorbell transformers are, hence > the small diameter wire used for same. > > Stepping it down by .75 ohms with 3 resistors then through a 4.5 volt > beeper(?) complicates and weakens something that wasn't that powerful at the > getgo. > Kind of like taking a studio piano and converting it to a spinet, it > probably could be done but why would you want to? > > As I said in my original post, I found that good old acohol and water works > better, it may not be as fast but it lasts longer. > > The results of the Zapper are, IMHO and experience temporary. > > Mike > >> -- >> >> It is the mark of an educated mind to be able to entertain a thought >> without accepting it. >> >> Aristotle (384 BC - 322 BC) >> >> Michael Magness >> Magness Piano Service >> 608-786-4404 >> www.IFixPianos.com >> email mike at ifixpianos.com >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100304/dcccf7ab/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC