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Old May 19th, 2013, 03:50 AM   #16
Goody
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Replaced a 415V coil with a 48V coil. I only mention it because the explosion was so spectacular.
But not as spectacular as when I connected the lives to the motor terminals and the motor wires to the 'live in' terminals on a 12KW inverter.
They go with a bang as good as any dynamite.

Oh, and don't test the voltage on a HT lead to the spark plug on a gas burner with your digi meter - they don't like it.

Last edited by Goody; May 19th, 2013 at 04:04 AM.
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Old May 19th, 2013, 05:25 AM   #17
Donnchadh
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Hi

Also am after having a few.

I wired a 3 phase 220 volt drive that came from the USA with our 3 phase which is 380 volt for some reason the drive did not like it. The pm over the project asked me what happened and I told him and to be fair he said it did not understand but how much time will it cost. I told him it would take a week and he just said ok. I did wonder why he was so understanding till I heard that the day before he had caused about 10k of damage.

I was also in a robot cell and it was the first time I used multi move system. There I was trying to jog a robot and could not understand why it was not moving until I heard a crunch, I was moving the wrong robot and just drove the head it to a moving conveyor another 3 k to fix that one

But as a saying goes in Ireland
The man who never made a mistake , never made anything

Donnchadh
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Old May 19th, 2013, 09:19 AM   #18
jstolaruk
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Quote:
Originally Posted by Donnchadh View Post
Hi

I was also in a robot cell and it was the first time I used multi move system. There I was trying to jog a robot and could not understand why it was not moving until I heard a crunch, I was moving the wrong robot and just drove the head it to a moving conveyor another 3 k to fix that one
sweet
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Old May 19th, 2013, 01:35 PM   #19
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How about the PLC-2/17 (with Power-supply) user who called me when I worked for A-B tech support asking if the 1-sh-2 on his brand new PLC-5/15 meant the same thing as L1-L2-Gnd on his trusty PLC-2/17. Naturally he called after plugging it in. Did someone mention magic smoke?
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Old May 19th, 2013, 02:07 PM   #20
Zimmer
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Years ago, one of those "chart recorders" that displayed all the plant info. I had it connected to the laptop, for no reason other than I thought I would be really clever and back it up in case it died.
I found out there is a big difference between the
transfer recorder to pc button
and the one I pressed
the transfer pc to recorder button.

Result, all info lost
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Old May 19th, 2013, 03:13 PM   #21
TheWaterboy
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This one still hurts...

I'm not a electronics engineer but in a previous attempt at making my fortune I became one and I designed a 3 axis stepper controller board for a startup company I was part of. It had many surface mount parts including 2 100 pin SMTs and one PLCC thru hole socket for the newly developed 68HC11F1 processor. I was in DEEP!

I designed and breadboarded the circuit, which worked as expected, so I proceeded to lay out the board using PCB design software. Because of my inexperience with the nuances of PCB copper routing when surface mount devices are involved (normally this is shopped out to someone who does it all the time) it took me a very long time to get it right and I was focused on the SMT devices.

I took for granted that most parts at the time start pin numbers at a corner, the HC11 didn't. It had pin 1 in the middle of a side. I didn't even think to look at the datasheet for that so my prototype boards had the wrong pinout. It's common now but wasn't in the world I lived in so it came as quite a surprise.

I wound up making an adapter board to rotate the pins and soldering this lump onto my beautifully laid out board. It worked but the company died for (thankfully) unrelated reasons so regretfully I never got to fix my "educational experience".
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Old May 19th, 2013, 10:40 PM   #22
Tom@Pton
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Mine was when I downloaded a change to a program, the whole line started. We were in a test stage and everyone knew but still. The E-stop worked.
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Old May 20th, 2013, 05:24 AM   #23
nehpets
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On an Assembly Line producing Car cylinder heads, all 50 PLC5 & Slc500's were on the DH+, I had to download a new program to drop node 15, I was using Icom's software (pre RSlinxs) without thinking went ahead with the download not realizing that the Icom software defaulted to drop node 0, the first I knew of it was the whole line came to a stop because station node 0 had the wrong program in it.

Steve
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Old May 20th, 2013, 07:15 AM   #24
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I was Installing a new RX3i PLC and Emerson servo with a Delta Motion controller. A fellow Worker Thought a fan needed replaced in a VFD on the same machine at the same time. As I was just finishing up my last programming and pleased with my results. He flipped the switch to the VFD to see if the little fan in the VFD came on. At that moment I heard Fireworks coming over from his direction but the smoke was in my cabinet right before my very eyes lights from the PLC went out Smoke rolling out of a Delta motion controller before I knew what happened. 1 New PLC 1 New Chassis 2 Power supply's and A Motion controller later.

2 Making Changes to a program thinking you are downloading to your test PLC when you hear the whole line shut down and people yelling for you. Realizing you just downloaded to the Real working PLC on the Floor and Brought the Mill to it's knees. Suprising how fast you can scramble and undo what you have done when seconds feel like minutes.
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Old May 20th, 2013, 09:29 AM   #25
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I've had so many, it's hard to pick the worst. Certainly a contender was after I hit the E-Stop on a 700 hp blower. I heard the starter drop out, and let go the E-Stop. There was something wrong in the wiring, and the motor got full voltage while spinning at almost full rpm. The sound of the coupling snapping was like a bomb going off. The blower was trashed, and I learned to use latching E-Stops.
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Old May 20th, 2013, 11:27 AM   #26
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Everything in life happens for a reason.
Sometimes that reason is you being stupid.

I can identify with many of the above.
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Old May 20th, 2013, 12:57 PM   #27
brstilson
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Last week I smoked a customer's cylinder prox because I wired it to the terminal block wrong. It was one of those little Bimba proxes. Thing was half melted.

Once I touched a Devicenet cable and the entire machine went down. Although that's pretty much to be expected with DeviceNet. I learned to never touch anything on a Devicenet Network while the machine is running.

All the times I misdiagnosed something and had my employer change a part that didn't need to be changed. Now I have a policy where if I can't determine which part of a system is broken, I replace the cheapest parts first (cables, connectors, etc.).

What I've seen other people do:

This guy who worked at my last job had been a fourth year electrician apprentice. His career ended shortly after not being able to trace a circuit to shut it off and opting to cut the entire conduit...live...with a pair of large cutters instead. I normally wouldn't believe such stories except that he was the one who actually told it.

Another time, this same guy couldn't figure out why a drive wouldn't run. He's very much a "do SOMETHING, ANYTHING, until it works" kind of guy. His method of troubleshooting is "change parts until the problem goes away." By the time I got to the machine, I opened the door to see a contactor, hanging in mid air by the wires, which were attached to the line terminals on the drive with the power coming in, and the motor leads on the other side of the contactor. He used a selector switch that he had likewise thrown into the panel to manually turn the motor on and off. The problem? The analog output card on the controller was bad.

But by far the most expensive mistake I've ever seen was at a systems integrator I was doing CAD work for. We had a few systems with a DeviceNet (ugh) network. The system was set up with a main PLC rack, and a remote I/O rack on each zone all networked together. Each piece of equipment had a good dozen or more remote racks on them. The main processor for each system was a Control Logix processor. The engineer ended up ordering a Processor for every remote rack, on multiple machines. Now, one of these processors will run you a good $5,000 or more, at least, that was true back then. Now imagine ordering 50 more than what you need. In case you don't have your calculators out, this is a $250,000 mistake. The engineer was fired (being 45 minutes late to work every day on top of that doesn't help things). The A-B rep had to order extra stock from the factory to fill the order, so even though the processors could be returned, that's one hell of a restocking fee.

Last edited by brstilson; May 20th, 2013 at 12:59 PM.
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Old May 20th, 2013, 02:32 PM   #28
brstilson
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Quote:
Originally Posted by Donnchadh View Post

But as a saying goes in Ireland
The man who never made a mistake , never made anything

Donnchadh
That's being stolen for my sig line.
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Old May 20th, 2013, 06:22 PM   #29
Ned_Flanders
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Quote:
Originally Posted by brstilson View Post
Last week I smoked a customer's cylinder prox because I wired it to the terminal block wrong. It was one of those little Bimba proxes. Thing was half melted.

Once I touched a Devicenet cable and the entire machine went down. Although that's pretty much to be expected with DeviceNet. I learned to never touch anything on a Devicenet Network while the machine is running.

All the times I misdiagnosed something and had my employer change a part that didn't need to be changed. Now I have a policy where if I can't determine which part of a system is broken, I replace the cheapest parts first (cables, connectors, etc.).

What I've seen other people do:

This guy who worked at my last job had been a fourth year electrician apprentice. His career ended shortly after not being able to trace a circuit to shut it off and opting to cut the entire conduit...live...with a pair of large cutters instead. I normally wouldn't believe such stories except that he was the one who actually told it.

Another time, this same guy couldn't figure out why a drive wouldn't run. He's very much a "do SOMETHING, ANYTHING, until it works" kind of guy. His method of troubleshooting is "change parts until the problem goes away." By the time I got to the machine, I opened the door to see a contactor, hanging in mid air by the wires, which were attached to the line terminals on the drive with the power coming in, and the motor leads on the other side of the contactor. He used a selector switch that he had likewise thrown into the panel to manually turn the motor on and off. The problem? The analog output card on the controller was bad.

But by far the most expensive mistake I've ever seen was at a systems integrator I was doing CAD work for. We had a few systems with a DeviceNet (ugh) network. The system was set up with a main PLC rack, and a remote I/O rack on each zone all networked together. Each piece of equipment had a good dozen or more remote racks on them. The main processor for each system was a Control Logix processor. The engineer ended up ordering a Processor for every remote rack, on multiple machines. Now, one of these processors will run you a good $5,000 or more, at least, that was true back then. Now imagine ordering 50 more than what you need. In case you don't have your calculators out, this is a $250,000 mistake. The engineer was fired (being 45 minutes late to work every day on top of that doesn't help things). The A-B rep had to order extra stock from the factory to fill the order, so even though the processors could be returned, that's one hell of a restocking fee.
Ha - one of my colleagues is like this. If he cannot fix a machine he blames the program or looks in the stores until he finds a part we do not have and blames that instead.

His screw up was on a robot conveyor that didnt have any manual controls. He would dab 24 volts onto the coils of the contactors to get the conveyors to run. Except...one day he dabbed L1 instead of A1 thus shoving 415v AC into the Siemens plc. After a new cpu and 4 I/O cards, my next job was to fit manual controls!!!
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Old May 20th, 2013, 09:28 PM   #30
Lancie1
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The worst thing to ever happen to me was I walked into an old mothballed plant to get the lights on for some planned work in the building. I spent 30 minutes in the basement finding the various lighting circuits, checking for shorts, then turning on the circuit breakers for the lighting circuits, and replacing a few bulbs. Then I walked out again.

It was the worst day of my life, but I didn't even know it, and I didn't find out how bad it was until 2 years later, when I had shortness of breath and breathing difficulties, headaches, and other strange problems. My doctor said my lung X-rays looked like those of a 70-year old who had been smoking all his life. At the time I was 32 and had never smoked.

Now that I am old, my lungs look like those of a 100-year old. That building turned out to be highly contaminated with a chemical warfare agent, commonly called "mustard". Mustard agent is a solid until the temperature reaches 90 degrees F. That worst-thing-event for me happened to be on a 95-degree day in Denver, Colorado.

You never know when that worst thing is going to happen, and you may not even be aware of it until many years later.

Last edited by Lancie1; May 20th, 2013 at 09:32 PM.
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