I used to have a boss, may he rest in peace, who would wait till I had a arm deep in a piece of energetic gear and walk up and go "ennntttt" right behind me when I was concentrating on the gear at hand. Of course you want to jump, even when you know its powered down. Then he'd crack out laughing.,,,, Ohhhh I hated that.
The following is NOT funny, but it is a good point.
Little Thai postdoc, lady is a mathematician who should have never been in a lab, but I had to put up with her natural born destructiveness for 4 years. After 3.5 years in a HV based lab, you think she would know something about circuits. So I get in this shiny new 60Kv 500 uA adjustable supply. At 60, single pin Aldens like on henes are not a good idea. Our normal supplies were current limited and had a arc fault trip, and were intrensicly safe.This one, was not arc protected and limited. So unlike our 0-20 and 0-30 Kv supplies, this had a big piece of RG8 coax on it as the output. 6 inches of the outer jacket are stripped off and a PL259 connector is the ground, with the teflon inner part terminated deep inside the PSU with a bannana pin, so basically the the hot junction is 6 inches inside the potted multiplier and the cable is locked in place by the 259 shell. Nice way of doing it.
But for 3. 5 years this lady has been using aldens.
"Steeeweve (cant pronounce the e-ve pair in Thai) Dr Reneker said you are not supposed to no about this projecd" (Oh no, another one of these I'm not supposed to know, but I end up making it work ones) "I vant Rathapol's new powder suppli". Me "Ok, but this unit is lethal, it can kill you and I don't want you working alone, the cable is 35 Pf per foot, and stores a charge." The boss in one of his rare fits of stupidity, wanted this project compartmentalised, so he would not have to share the reward for the patent. So he sent the machine out to be built, and not by a person who know about HV. The frame had two huge AL plates about 2 " apart on standoffs.
So I insist that Ms Destructo leaves the door open and tells me if she goes above 30Kv. Her experiment should have thresholded around 20 Kv. Nothing in our lab would ever need to go to 60 to threshold. Ok, she can do it alone, shes been around HV for years. But I start to hear the hissing of HV leakage, and I'm getting concerned. I'm at a computer outside the door, and my ears are perking up. So screw the "secrets", safety of life trumps security unless your in the military.
When I hear the static go to sparks...sparks increasing, and I think, sparks.. We don't DO sparks, arcing kills the 1400$ psus. What has she done now... I didnt know about the big plates....
The desk lights go, out, a GFI trip, and before I can get close, I see her turning the knob, as you DON'T hurry into a lab accident, screech, scream, yow and she jumps back hard into a desk. HV stayed on, it was on another outlet, so I whacked the psu switch with a piece of PVC, and went to check on her.
Shes still standing , sorta slumped over the desk, I'm thinking ABCs, Airway, Breathing, Circulation. Then Spinal, Secondary reaction bone injury Shes somewhat conscious,breathing, but really stunned. I get her talking....
The classic "whyy diddd it dddooo that?????" comes out.....
(The third most common phase on cockpit voice recorders starts with WHy is it "
She didnt understand the need for the huge, long, coax, even after being briefed, so she took a TVS-15 cable (Television Voltage Service, you've all seen it) with a half Alden and rammed it up the hole where the RG8 core should have been, and proceeded to use that hastily improvised spark gap to charge two 36x24 AL plates, air spaced.... To about 70 Kv.
She could not understand why her experiment didnt threshold at 20 and kept turning the knob....
Whilest I do not recommend repremanding one's 76 year PHD boss behind closed doors, in his own office, ............
Shes fine, now very rich, has kids, and still doesn't know what a complete circuit is.
Oh, and you keep the PVC handy in a electical lab, to knock people off circuit, You dont touch them. And we were told, if a alarm is going off, You do not go in, screw your coworkers, you leave. I personally disagreed with that policy in non chemical labs...
I only had three minor accidents in 8 years, and two of them were me, she's the only one that got even close....
Now do you guys understand why I have high BP??
Steve
Last edited by mixedgas; 06-01-2009 at 05:31.
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...