<div dir="ltr"><div><div><div><div><div>Hi, folks new to the list.<br><br></div>Stupid shop things. I had an out of town customer who had purchased and returned in succession two high priced ceiling fans ~$500 each (this was a while ago). For the third attempt to get him a working one, I used an extension cord and two alligator clips to rig a test cable. I remembered to only attach one clip at a time which was fine until I steadied the fan housing with one hand and picked up the second clip with the other. Only 110 but right across the chest. <br>
<br></div>On a later occasion, I was working with 1/2" plywood sheet. and a radial arm saw. I measured out the cuts with a large square, set up the saw and prepared to cut. I couldn't figure out where I put the square but figured it must be somewhere safe. I started the first cut, there was a loud clang and the square hiding under the plywood shot through two layers of drywall in the wall behind the saw. That was a little unnerving.<br>
<br></div>Fortunately both of those are well in the past.<br><br></div>The most recent one - I had my laptop hooked up to the USB port on my Mendel printer. I was getting ready to unhook everything to move the printer when I snagged that cable and popped the USB socket off the board. That would have been ok since I still had comms through the port, but I decided to be clever and solder the socket back down. That would have been fine too had I noticed the tiny solder bridge to an open pad on the board. Of course I powered up and fried the board. Ouch. Luckily I had a slave board and was able to switch out the firmware. <br>
<br></div><div>Pat<br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Jun 26, 2013 at 12:21 PM, Richard Guy Briggs <span dir="ltr"><<a href="mailto:rgb@tricolour.net" target="_blank">rgb@tricolour.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Wed, Jun 26, 2013 at 11:53:52AM -0400, James Allanson wrote:<br>
> Multiple Ultimaker burns, from my own Ultimaker as well as the first<br>
> Artengine Ultimaker. Usually doing something stupid like cleaning the bed<br>
> while the machine is moving the heated head around. I don't think I've<br>
> learned my lesson on that one as I've made the same mistake many times.<br>
> But I have been conditioned now to yank my hands out of the machine when I<br>
> hear the stepper motor(s) engage.<br>
><br>
> I did learn I have an extremely foul mouth when I burn myself though. :D<br>
<br>
</div>Heh, I do tend to have a much more foul mouth with inanimate objects<br>
when I think nobody else can hear me. ;-) It usualy comes from bikes<br>
or parts thereof not staying where they were put, falling on me when<br>
trying to get at something else in storage in our overcrowded garage...<br>
<div class="HOEnZb"><div class="h5"><br>
> On Tue, Jun 25, 2013 at 8:07 AM, mike Jans <<a href="mailto:mjans@live.com">mjans@live.com</a>> wrote:<br>
> > I had a similar experience at a young age, I had a habit of prying things<br>
> > open to see what they had on the inside. I got my hands on a disposable<br>
> > camera and used a flat screw driver and a pocket knife to pry it open. I<br>
> > couldn't see it, but I managed to get each tool on each of the capacitor's<br>
> > leads. I sat for a couple of minutes trying to understand what had happened<br>
> > and then I went to tell my dad. He showed me what happens when you short a<br>
> > full charge. I still have that screwdriver with those scars on it somewhere.<br>
> ><br>
> > > Date: Mon, 24 Jun 2013 17:31:13 -0400<br>
> > > From: <a href="mailto:rgb@tricolour.net">rgb@tricolour.net</a><br>
> > > To: <a href="mailto:jason.cobill@gmail.com">jason.cobill@gmail.com</a><br>
> > > CC: <a href="mailto:lab@artengine.ca">lab@artengine.ca</a><br>
> > > Subject: Re: [Lab] Open Question: Dumbest Thing You've Done While Making<br>
> ><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<br>
> > current!<br>
> > > > What kind of motor was all that power being used to drive? I was under<br>
> > 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 <<a href="mailto:rgb@tricolour.net">rgb@tricolour.net</a><br>
> > >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<br>
> > dumbest<br>
> > > > > > thing you should have caught before you nearly set your house on<br>
> > fire?<br>
> > > > > What<br>
> > > > > > did you learn from it?<br>
> > > > > ><br>
> > > > > > Me first: I plugged in a table saw without checking the switch<br>
> > first -<br>
> > > > > > it was on. And it was covered in 2x4s and sheetwood scraps, which<br>
> > 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<br>
> > out of a<br>
> > > > > wood-cabinet vacuum tube TV set. I had learned to solder when I was<br>
> > about<br>
> > > > > 8.<br>
> > > > > I knew which side was the primary and I wanted to test the<br>
> > secondaries. I<br>
> > > > > knew<br>
> > > > > they would be high. I had a cheap analog multimeter from Radio Scrap<br>
> > 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<br>
> > 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<br>
> > Ottawa,<br>
> > > > > I was working on the U of Ottawa solar rayce car RALOS-II, wiring up<br>
> > 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<br>
> > to 7<br>
> > > > > car batteries in series (90VDC, 1000A?). As I pulled my hands away<br>
> > 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<br>
> > for<br>
> > > > > the car to avoid any further incident, one of my teammates packed me<br>
> > 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<br>
> > 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<br>
> > 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<br>
> > very<br>
> > > > > lucky it didn't instead hit the iron ring on the adjacent finger<br>
> > 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>
> > > > > <a href="http://hpv.tricolour.net" target="_blank">hpv.tricolour.net</a>><br>
> > > > > <<a href="http://www.TriColour.net" target="_blank">www.TriColour.net</a>> -- \___ o \@ @ Ride yer<br>
> > > > > bike!<br>
> > > > > Ottawa, ON, CANADA -- Lo_>__M__\\/\%__\\/\%<br>
> > > > > Vote! -- <<a href="http://greenparty.ca" target="_blank">greenparty.ca</a><br>
> > > > > >_____GTVS6#790__(*)__(*)________(*)(*)_________________<br>
> > > > ><br>
> > ><br>
> > > > _______________________________________________<br>
> > > > Lab mailing list<br>
> > > > 1. subscribe <a href="http://artengine.ca/mailman/listinfo/lab" target="_blank">http://artengine.ca/mailman/listinfo/lab</a><br>
> > > > 2. then email <a href="mailto:Lab@artengine.ca">Lab@artengine.ca</a><br>
> > ><br>
> > ><br>
> > > slainte mhath, RGB<br>
> > ><br>
> > > --<br>
> > > Richard Guy Briggs -- ~\ -- ~\ <<a href="http://hpv.tricolour.net" target="_blank">hpv.tricolour.net</a>><br>
> > > <<a href="http://www.TriColour.net" target="_blank">www.TriColour.net</a>> -- \___ o \@ @ Ride yer bike!<br>
> > > Ottawa, ON, CANADA -- Lo_>__M__\\/\%__\\/\%<br>
> > > Vote! -- <<a href="http://greenparty.ca" target="_blank">greenparty.ca</a><br>
> > >_____GTVS6#790__(*)__(*)________(*)(*)_________________<br>
> > ><br>
> > > _______________________________________________<br>
> > > Lab mailing list<br>
> > > 1. subscribe <a href="http://artengine.ca/mailman/listinfo/lab" target="_blank">http://artengine.ca/mailman/listinfo/lab</a><br>
> > > 2. then email <a href="mailto:Lab@artengine.ca">Lab@artengine.ca</a><br>
> ><br>
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> > 2. then email <a href="mailto:Lab@artengine.ca">Lab@artengine.ca</a><br>
> ><br>
<br>
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<br>
<br>
slainte mhath, RGB<br>
<br>
--<br>
Richard Guy Briggs -- ~\ -- ~\ <<a href="http://hpv.tricolour.net" target="_blank">hpv.tricolour.net</a>><br>
<<a href="http://www.TriColour.net" target="_blank">www.TriColour.net</a>> -- \___ o \@ @ Ride yer bike!<br>
Ottawa, ON, CANADA -- Lo_>__M__\\/\%__\\/\%<br>
Vote! -- <<a href="http://greenparty.ca" target="_blank">greenparty.ca</a>>_____GTVS6#790__(*)__(*)________(*)(*)_________________<br>
<br>
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</div></div></blockquote></div><br></div>