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Take a Walk Into the Wall of Flame

We all have seen the many types of Halls of Fame out there, from sports to rock 'n' roll, but how about a different type of recognition. How about a special group for all the hard-working engineers out there? This is the group for whom, regardless of how good you are or what you've previously designed or accomplished, you still had that one moment where you blew up your board or your test equipment or shocked yourself. It's for these moments and for these engineers that I want to create the Wall of Flame.

I'll nominate myself first and explain why I should be in with a few stories of my own. Then I will turn it over to the rest of the world. I like to call this my Top 3 dumb electronic moments of all time.

Moment number three was the time I was doing some high temperature and humidity testing. I was called into the lab to check and make sure the board was still working after the first phase of the testing. I was anxious to make sure this board was still functioning. So anxious that I forgot to unplug the circuit.

As I rested by right hand on the large metal cabinet of the temp tester, I picked up the board with my left hand. I touched a couple of the solder pads with line voltage on them. I felt the current shooting through me into the metal cabinet. After pulling my hand away from the tester, I casually laid the board down, looked around to make sure no one had seen me make a fool of myself and walked away. Oh yeah, and like me, that board lived to work another day.

Moment number two was the day I was sitting in the lab testing my motor control designs and doing some motor testing. One of the tests was to operate the motor at various voltages. Our test required us to operate a 120V fan motor at 170V for a short duration. The intent was to make sure that the motor did not fail.

It was just one of those days. I dropped my pen on the floor and it rolled about five feet away. As I stood up walked over to pick it up, I accidentally hit and turned the voltage knob up to about 290V. Let me tell you, it doesn't take much time at all to see small copper commutator bars flying out of a motor at probably 200 miles per hour at that amount of over-voltage. That's when you stop, drop, roll, and pull the plug.

Finally, the worse moment of all time at number one. It was the week we were scrambling with everyone in panic mode trying to get a full working prototype ready for the very important customer meeting that was going to happen at the end of the week. I was hand building and wiring all the boards and the appliance. It took me about four hours to build the main processor board.

It was about 10 p.m. I was tired, hungry, and all alone in the lab. I had just finished soldering that last piece of 30AWG jumper wire onto the board. I hooked up all the boards, took out the meter and checked some voltages, and everything was working perfectly. I noticed one of the 50 wires I had previously soldered onto the board was barely hanging by a solder whisker. I laid the board down, switched on the soldering iron, and went in to make a better connection.

It seemed like everything turned into slow motion as I went in and touched the nice shiny soldering iron tip to the solder pads on my four-hour creation and realized that I not unplugged the circuit. I heard what sounded like a shotgun being fired next to me and watched a flame blow a two-inch circle right in the center of my board. You never want this to happen late at night when the customer meeting is the next morning and everything has to be perfect.

I think these experiences make me a good candidate for the Wall of Flame. Let me know what crazy moments you may have had that would make you worthy for induction into this great group.

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7 comments on “Take a Walk Into the Wall of Flame

  1. David Maciel Silva
    September 30, 2013

    Jason,

    His esperiências are great, they will be difficult to overcome but also have some that are at least curious:

    3: It was still a student of electronic, I was home trying demontar one radio and do other work, my friend had already disassembled the radio and it was taking components, it just would not stop working for nothing, mine had a defect I could not find in a moment of anger, I kicked my radio and accidentally enconstei the soldering iron that was between my toes …

    2: I have worked in this area had a prototype that was to be presented the other day, I had never seen such a plate welded wire, after much pressing was ready, box stuffed with either wire, yellow, functional! The customer came and went crazy life, “BOX HAD TO BE BLACK”. Soon my effort did not show up …. So lacked the fire ….

    1: Still in the same company working on a national holiday system rode interestingly was a camera and I was putting a uC to access all functions automatically as soon I took key by key and put the keys close to transistors, somebody called and the soldering iron was on the CCD, I waited almost three weeks for the camera arrived because it came from China, no explosions! I paid the “duck” again ….

  2. Vishal Prajapati
    October 1, 2013

    I have small experience with power electronics company. We were working on the prototype of Static Voltage Stabilizer. Our firmware was ready and we were excited to try it and show it to the top management next morning. We crancked up the suppy in the prototype. We were testing the waveform on the DSO, and suddenly from no where fly came near to MOSFETs in the circuit. They had 1200VAC across Drain and Source. The fly shorted D and S terminal and 4 among 8 MOSFETs where burned. No one could have stopped it.

  3. RedDerek
    October 1, 2013

    I just designed a transformer using a 20 pound cut c-core for a 900 Volt, 25 kW supply. The transformer used copper strips for the winding to deal with eddy currents. In between was isolation paper to keep the windings from shorting. A quick continuity test said things were ready to go.

    We put the transformer into the circuit and turn it on. It took a couple of minutes, but the transformer found a place to short and arcing occurred between the winding and the core. The power supply control operated flawlessly – turn on, see over current, turn off, repeat. With all the arcing, smoke soon appears, and then flames.

    The othe engineer said, “What do I do?”. I remarked, “Pull the breaker switch!” That was easier said than done for the circuit laid between the engineer and the 400 cycle 440 Vac, 30 Amp pull-bar. I added the additional comment, “Don't miss the switch!”

    Once we got things under control, it was now time to tell maintence to turn on the fans and not worry about any smoke reports (it poured out of the lab as I walked out the door). This was on the second floor, inside room, and no windows on the floor. Took a few hours, but all got back to normal.

  4. WKetel
    October 2, 2013

    This individual should never be allowed withiin twenty feet od a soldering iron.

  5. WKetel
    October 2, 2013

    We were in the startup phase of commisioning an industrial testing machine, which was controlled by a computer in an STD buss cardrack. Unfortunately the rack was below the 480 volt three-phase diconnect switch.  I had to push the reset button on the processor quite a few times, and after one such press the sweaty back of my hand connected with the terminal on the disconnect switch. I jumped back about 8 feet and let out a yell, because the shock was quite startling. It gave everybody else quite a scare. Then we got back to work. I had the presence of mind to caution my co-workers not to stand behind me when I was resetting the processor board, explaining that I did not want anybody getting hurt on the job.

  6. RamRod
    October 3, 2013

    This reminds me of something I read years ago (in EET or ED?), titled something like the 10 Commandments of Electrical Safety. I don't know who the original author is.

    Here is a web-link to the same thing (and there are other variations):

    http://www.eng.auburn.edu/~troppel/tencom.html

    Number 8 is my fave – I laugh every time I read it!

     

  7. jlinstrom
    November 18, 2013

    I was a Q.A. engineer in a prior life. Did a Hi-pot test on a long marine tow cable (coax). They have a decent capacitance, yes?

    When the cable passed the test, I reached out to unclip the tester leads. It was only a stupo-second after I grabbed the leads that the term “Bleeder Resistor” flashed thru my mind. Gravel on the knees and a tipped over equipment cart later, I finished and documeted the test like a good boy.

    Let's hear it for low votlage logic!

    john

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