[Lab] Open Question: Dumbest Thing You've Done While Making
mjans at live.com
Tue Jun 25 08:07:07 EDT 2013
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.
> Date: Mon, 24 Jun 2013 17:31:13 -0400
> From: rgb at tricolour.net
> To: jason.cobill at gmail.com
> CC: lab at artengine.ca
> Subject: Re: [Lab] Open Question: Dumbest Thing You've Done While Making
> On Mon, Jun 24, 2013 at 04:53:04PM -0400, Jason Cobill wrote:
> > That's amazing! I had no idea the uO solar car generated that much current!
> > What kind of motor was all that power being used to drive? I was under the
> > impression it was a tiny motor running at high RPM and geared down for
> > torque.
> It was a Uniq Mobility 10kW motor. That motor/controller combination
> wasn't nearly as effective at shorting out the battery pack as a small
> gold ring. ;-) Much of the competition was using Solectria motors at
> that time. Within about 5 years, pretty much the entire field had
> switched over to in-wheel motors made by New Generation Motors (NGM), a
> company founded by a number of George Washington University solar car
> team members.
> > Zot's a pretty cool nickname, though. ;)
> It makes me think of the "BC" comic strip... (I say this as I watch a
> huge black cloud criss-crossed by jagged white lines completely fill my
> large west-facing 4th-floor window at UQO on Tache in Gatineau.)
> > -Jason Cobill
> > On Mon, Jun 24, 2013 at 4:49 PM, Richard Guy Briggs <rgb at tricolour.net>wrote:
> > > On Mon, Jun 24, 2013 at 04:00:51PM -0400, Jason Cobill wrote:
> > > > Experiments gone wrong? Tools gone out of control? What's the dumbest
> > > > thing you should have caught before you nearly set your house on fire?
> > > What
> > > > did you learn from it?
> > > >
> > > > Me first: I plugged in a table saw without checking the switch first -
> > > > it was on. And it was covered in 2x4s and sheetwood scraps, which it
> > > > proceeded to launch across the garage and nearly take out a window.
> > > > It _should_ have been off, but I _should_ have checked. So now I
> > > check.
> > > > Every. Time.
> > >
> > > Oh, this one's easy. ;-) I have two related to electricity.
> > >
> > >
> > > 1) When I was about 10 I had a power transformer that I had taken out of a
> > > wood-cabinet vacuum tube TV set. I had learned to solder when I was about
> > > 8.
> > > I knew which side was the primary and I wanted to test the secondaries. I
> > > knew
> > > they would be high. I had a cheap analog multimeter from Radio Scrap with
> > > a
> > > 750V rating. I carefully attached and shielded the primary wires to a
> > > standard two-prong plug. I was sitting on my bed (so no danger of
> > > grounding out, plus it was an isolated secondary). I pinched one
> > > secondary wire with the meter test lead, then grabbed the second test
> > > lead and went to pinch it with the other secondary... (It was about 350V.)
> > > I haven't done that ever again! Now I used insulated leads.
> > >
> > >
> > > 2) In my last year of Electrical/Computer Engingeering at U of Ottawa,
> > > I was working on the U of Ottawa solar rayce car RALOS-II, wiring up the
> > > main power backplane of the car (I was the Electrical Systems
> > > Co-ordinator) working on some low-voltage wires on one card that
> > > happenned to be facing a high-voltage, high-current card connected to 7
> > > car batteries in series (90VDC, 1000A?). As I pulled my hands away from
> > > my work something sparked. Naturally I pulled back, jamming my family
> > > gold ring into the high-voltage card. Once the sparks stopped, two of
> > > my fingers were black. After a quick throw of the main power switch for
> > > the car to avoid any further incident, one of my teammates packed me off
> > > to the hospital to clean things up. On the way to the hospital, I was
> > > babbling with all the wire cross-sectional diameters, materials and
> > > resistances per metre still fresh in my mind, calculating that must have
> > > been a 100kW arc welding burn.
> > > I was lucky. I still have all my fingers, but one has an
> > > interesting ring-shaped scar (that was 20 years ago this month) and the
> > > bloodstone with the family crest in the ring cracked. I thought of
> > > getting it repaired, then decided to leave it as a reminder. I was very
> > > lucky it didn't instead hit the iron ring on the adjacent finger that I
> > > had earned not 2 months prior. Gold is a much better conductor, so it
> > > didn't heat up much compared with the other parts involved. The two
> > > one-inch spade terminals on the card along with 1/2" PC board traces
> > > vanished. I had to check a second identical card to find out what was
> > > there. I earned the nicname "Zot" for that one...
> > > I now remove my rings when working with high voltage/current.
> > >
> > >
> > > I still love electricity! :D
> > >
> > >
> > > > -Jason Cobill
> > >
> > > slainte mhath, RGB
> > >
> > > --
> > > Richard Guy Briggs -- ~\ -- ~\ <
> > > hpv.tricolour.net>
> > > <www.TriColour.net> -- \___ o \@ @ Ride yer
> > > bike!
> > > Ottawa, ON, CANADA -- Lo_>__M__\\/\%__\\/\%
> > > Vote! -- <greenparty.ca
> > > >_____GTVS6#790__(*)__(*)________(*)(*)_________________
> > >
> > _______________________________________________
> > Lab mailing list
> > 1. subscribe http://artengine.ca/mailman/listinfo/lab
> > 2. then email Lab at artengine.ca
> slainte mhath, RGB
> Richard Guy Briggs -- ~\ -- ~\ <hpv.tricolour.net>
> <www.TriColour.net> -- \___ o \@ @ Ride yer bike!
> Ottawa, ON, CANADA -- Lo_>__M__\\/\%__\\/\%
> Vote! -- <greenparty.ca>_____GTVS6#790__(*)__(*)________(*)(*)_________________
> Lab mailing list
> 1. subscribe http://artengine.ca/mailman/listinfo/lab
> 2. then email Lab at artengine.ca
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Lab