I’m still feeling pretty lethargic, but I hope that will improve when I get to lecture about the EPR paradox in Quantum Optics today (it’s going to be kind of a short lecture, unless I can ad-lib an introduction to Bell’s Theorem at the end of the class, but then I’ve been holding them late for three weeks already…). In an effort to perk myself up through blogging, here are some amusing tales about mishaps involving electricity.
(First, a disclaimer: Though these stories are presented in a manner that (hopefully) makes them sound amusing, most of what I describe here is, in fact, incredibly stupid. It’s a wonder I’m still alive, I’m such a jackass. Please be careful around high-voltage sources.)
Idiocy below the cut. The common theme (other than electrocution) is the oft-cited definition of insanity as “doing the same thing over and expecting a different result.”
Story the First: Beginning with the lowest voltage, and lowest level of stupidity, there was a power strip bolted to the side of an equipment rack in my lab in grad school. It was kind of old, so you really needed to haul on a plug to get it back out, and the best procedure was to put one hand on the top of the strip, while pulling the plug out with the other.
Of course, the other charming feature of the power strip in question was that it had a cracked fuse cover. Meaning that there was an exposed metal bit with line voltage on it, right at the top of the strip. Which I discovered one day when I was swapping a bunch of components in and out, and kept plugging and unplugging power supplies. Every time I unplugged something, I felt this stabbing pain in my left hand, which I’m embarassed to say I didn’t connect with the power strip until about the third time it happened. And then, having realized what the problem was, I confirmed it by…. touching the top of the broken fuse cover, and shocking myself again.
Story the Second: In grad school, I was working with metastable rare-gas atoms (specifically, metastable xenon). These atoms need to be put in an excited state before you can do laser cooling with them, or even spectroscopy so you can stabilize your laser to the atomic signal, so we cycled through a variety of different schemes for creating a plasma discharge as a reference source.
The source we used when I first got there was a DC discharge, based on an old HeNe laser tube, which worked by running a miliamp or so of current through the gas between two electrode with 800 V or so between them. This was set up out in the middle of a 4’x8′ optical table, so it was difficult to bump into by accident.
However, another feature of the lock circuit was an acousto-optical modulator that needed daily adjusting to tweak up the signal. The AOM wound up placed so that one of its adjustment knobs was a few inches away from the exposed hot electrode of the discharge cell.
To tweak the lock signal up, you needed to make small adjustments to this knob, and look at how they affected the size of the peaks on an oscilloscope trace. The previous student, who set the whole thing up, was a good eight inches shorter than I am, so he did this by walking around the table to adjust the knob, then walking back to see the effect, and repeating as necessary.
Being both tall and lazy (laziness is the father of invention), I figured out that I could reach the adjustment knob from the same side of the table as the scope. This, however, put my hand right next to the high-voltage electrode, at a time when I was necessarily looking the other way, at the scope.
Which is how it came to be that I am intimately familiar with the feeling of eight hundred volts entering my left arm. The first time that happened, I said (once I stopped hopping around the lab saying “fuckfuckfcukfuck”), “Well, I’ll be sure never to do that again.”
The fourth time it happened, we decided to change to an RF-based excitation scheme, that didn’t involve high voltage at all.
I have more stupid electrical tricks stories, but this ought to be enough for one post. And I’m a little more awake now…
Thank you for another great story! I have been sending your True Lab Stories to my daughter who’s taking ChemE, and she is thankful and appreciative too! Keep thos Lab Stories coming! Maybe a book down the road?
“The fourth time….”
You caught me with a mouthful on that one…. darn you.
Thanks for sharing.
DPG
I’m sure a hamster would only have needed one shock to learn its lesson.
[/simpsons reference]
File these stories under the heading, “That’s what RTV is for.”
This lab story isn’t about repetition insanity, merely stupidity, but it seems to fit here. Doing my PhD I worked much with a high vacuum sputtering equipment for thin film production. My poster for the upcoming conference could do with some more curves on a particular graph when the necessary high vacuum meter, a ion gauge, died.
For once it wasn’t the ionisation tube, or even the back side fuses, so I had to open the instrument casing and replace some inner fuses as it turned out. Oddly enough it wasn’t possible to isolate the instrument with a switch. Powering down the equipment with its old mercury high vacuum pump would be a lost day so I decided to make a hot repair for once.
Of course the disconnected cables slipped and shortcircuited even though I had tried to tape the naked ending. The first result was that the transformer supplying the electronics caught a coil fire. The second was that a fuse supplying most of the lab blow.
After isolating all equipments vacuum chambers while getting some unhealthy coil isolation fumes in my lungs, it turned out that the blown fuse wasn’t the lab primary 16 A but a remote 25 A that delivered to parts of two labs. This was the largest fuse blown in the facility for some years so I got quite a macho reputation. It turned out that most of the lab was wired to one phase which was why the primary fuse didn’t work well.
The upside was that the lab was later rewired for more robust and less noisy power. The downside was that the burnt transformer was not a stock item, so it took 3 weeks to replace it with an expensive special built one. Which of course was after the conference…
“The fourth time….”
You caught me with a mouthful on that one…. darn you.
We did have other reasons for switching, but the frequent near-electrocution episodes were a good incentive as well…
Of course the disconnected cables slipped and shortcircuited even though I had tried to tape the naked ending. The first result was that the transformer supplying the electronics caught a coil fire.
Ah, yes, burning electrical components…
That reminds me of a couple of good electrical fire stories, but I’ll save those for the next round of True Lab Stories…
Interestingly enough f^n was what I said when the HV from a kylstron power supply slipped across my leg…….
Then there was the time I came into the lab on Monday and saw a shards of a flow tube blow 10 m across the lab and embedded in the top of the wall. Turns out an undergrad was fooling around with the system and thought increasing the pressure was a cool thing to do. Blew right past him and did not leave a scratch, but we put a red circle around the damage on the wall and never repaint it
However, the really scary stories are chemical in nature, such as when I came into a lab and saw some guy transferring cyanogen to a cold finger and he was worried that nothing was coming out of the cylinder, except that he had about 5 cm of liquid in the cold finger. He was simply condensing it.
” shards of a flow tube blow 10 m across the lab” – A similar thing scared the hell out of me at school (so long ago many of my teachers were pre-hominid) in Chemistry class; some dimwit manged to turn one of those expensive Leibig stills that look like a stack of glass pears into a good approximation of a Nike missile, launching it up through the acoustic ceiling tiles and raining hot, sharp, contaminated glass splinters across the lab.
I gave up Chemistry.
My version of this story comes from undergraduate Intermediate Lab… the Milikan oil drop experiment. 300 Volts between the metal plates, a dark room, a quarter sized radioactive source held between the fingers and held close to the chamber to change the charge on the drops and…
And how far apart are the charged plates? About the same distance as your fingers when you hold the radioactive source. Stray a little too close in the dark, and…
*BZZZZZZZZZT*!!
Good times…