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<body class='hmmessage'><div dir='ltr'>I had a similar experience at a young age, I had a habit of prying things open to see what they had on the inside. I got my hands on a disposable camera and used a flat screw driver and a pocket knife to pry it open. I couldn't see it, but I managed to get each tool on each of the capacitor's leads. I sat for a couple of minutes trying to understand what had happened and then I went to tell my dad. He showed me what happens when you short a full charge. I still have that screwdriver with those scars on it somewhere.<div><br></div><div><br><br><div>> Date: Mon, 24 Jun 2013 17:31:13 -0400<br>> From: rgb@tricolour.net<br>> To: jason.cobill@gmail.com<br>> CC: lab@artengine.ca<br>> Subject: Re: [Lab] Open Question: Dumbest Thing You've Done While Making<br>> <br>> On Mon, Jun 24, 2013 at 04:53:04PM -0400, Jason Cobill wrote:<br>> > That's amazing! I had no idea the uO solar car generated that much current!<br>> > What kind of motor was all that power being used to drive? I was under the<br>> > impression it was a tiny motor running at high RPM and geared down for<br>> > torque.<br>> <br>> It was a Uniq Mobility 10kW motor. That motor/controller combination<br>> wasn't nearly as effective at shorting out the battery pack as a small<br>> gold ring. ;-) Much of the competition was using Solectria motors at<br>> that time. Within about 5 years, pretty much the entire field had<br>> switched over to in-wheel motors made by New Generation Motors (NGM), a<br>> company founded by a number of George Washington University solar car<br>> team members.<br>> <br>> > Zot's a pretty cool nickname, though. ;)<br>> <br>> It makes me think of the "BC" comic strip... (I say this as I watch a<br>> huge black cloud criss-crossed by jagged white lines completely fill my<br>> large west-facing 4th-floor window at UQO on Tache in Gatineau.)<br>> <br>> > -Jason Cobill<br>> > <br>> > On Mon, Jun 24, 2013 at 4:49 PM, Richard Guy Briggs <rgb@tricolour.net>wrote:<br>> > > On Mon, Jun 24, 2013 at 04:00:51PM -0400, Jason Cobill wrote:<br>> > > > Experiments gone wrong? Tools gone out of control? What's the dumbest<br>> > > > thing you should have caught before you nearly set your house on fire?<br>> > > What<br>> > > > did you learn from it?<br>> > > ><br>> > > > Me first: I plugged in a table saw without checking the switch first -<br>> > > > it was on. And it was covered in 2x4s and sheetwood scraps, which it<br>> > > > proceeded to launch across the garage and nearly take out a window.<br>> > > > It _should_ have been off, but I _should_ have checked. So now I<br>> > > check.<br>> > > > Every. Time.<br>> > ><br>> > > Oh, this one's easy. ;-) I have two related to electricity.<br>> > ><br>> > ><br>> > > 1) When I was about 10 I had a power transformer that I had taken out of a<br>> > > wood-cabinet vacuum tube TV set. I had learned to solder when I was about<br>> > > 8.<br>> > > I knew which side was the primary and I wanted to test the secondaries. I<br>> > > knew<br>> > > they would be high. I had a cheap analog multimeter from Radio Scrap with<br>> > > a<br>> > > 750V rating. I carefully attached and shielded the primary wires to a<br>> > > standard two-prong plug. I was sitting on my bed (so no danger of<br>> > > grounding out, plus it was an isolated secondary). I pinched one<br>> > > secondary wire with the meter test lead, then grabbed the second test<br>> > > lead and went to pinch it with the other secondary... (It was about 350V.)<br>> > > I haven't done that ever again! Now I used insulated leads.<br>> > ><br>> > ><br>> > > 2) In my last year of Electrical/Computer Engingeering at U of Ottawa,<br>> > > I was working on the U of Ottawa solar rayce car RALOS-II, wiring up the<br>> > > main power backplane of the car (I was the Electrical Systems<br>> > > Co-ordinator) working on some low-voltage wires on one card that<br>> > > happenned to be facing a high-voltage, high-current card connected to 7<br>> > > car batteries in series (90VDC, 1000A?). As I pulled my hands away from<br>> > > my work something sparked. Naturally I pulled back, jamming my family<br>> > > gold ring into the high-voltage card. Once the sparks stopped, two of<br>> > > my fingers were black. After a quick throw of the main power switch for<br>> > > the car to avoid any further incident, one of my teammates packed me off<br>> > > to the hospital to clean things up. On the way to the hospital, I was<br>> > > babbling with all the wire cross-sectional diameters, materials and<br>> > > resistances per metre still fresh in my mind, calculating that must have<br>> > > been a 100kW arc welding burn.<br>> > > I was lucky. I still have all my fingers, but one has an<br>> > > interesting ring-shaped scar (that was 20 years ago this month) and the<br>> > > bloodstone with the family crest in the ring cracked. I thought of<br>> > > getting it repaired, then decided to leave it as a reminder. I was very<br>> > > lucky it didn't instead hit the iron ring on the adjacent finger that I<br>> > > had earned not 2 months prior. Gold is a much better conductor, so it<br>> > > didn't heat up much compared with the other parts involved. The two<br>> > > one-inch spade terminals on the card along with 1/2" PC board traces<br>> > > vanished. I had to check a second identical card to find out what was<br>> > > there. I earned the nicname "Zot" for that one...<br>> > > I now remove my rings when working with high voltage/current.<br>> > ><br>> > ><br>> > > I still love electricity! :D<br>> > ><br>> > ><br>> > > > -Jason Cobill<br>> > ><br>> > > slainte mhath, RGB<br>> > ><br>> > > --<br>> > > Richard Guy Briggs -- ~\ -- ~\ <<br>> > > hpv.tricolour.net><br>> > > <www.TriColour.net> -- \___ o \@ @ Ride yer<br>> > > bike!<br>> > > Ottawa, ON, CANADA -- Lo_>__M__\\/\%__\\/\%<br>> > > Vote! -- <greenparty.ca<br>> > > >_____GTVS6#790__(*)__(*)________(*)(*)_________________<br>> > ><br>> <br>> > _______________________________________________<br>> > Lab mailing list<br>> > 1. subscribe http://artengine.ca/mailman/listinfo/lab<br>> > 2. then email Lab@artengine.ca<br>> <br>> <br>> slainte mhath, RGB<br>> <br>> --<br>> Richard Guy Briggs -- ~\ -- ~\ <hpv.tricolour.net><br>> <www.TriColour.net> -- \___ o \@ @ Ride yer bike!<br>> Ottawa, ON, CANADA -- Lo_>__M__\\/\%__\\/\%<br>> Vote! -- <greenparty.ca>_____GTVS6#790__(*)__(*)________(*)(*)_________________<br>> <br>> _______________________________________________<br>> Lab mailing list<br>> 1. subscribe http://artengine.ca/mailman/listinfo/lab<br>> 2. then email Lab@artengine.ca<br></div></div> </div></body>
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