Post by John on May 10, 2013 8:02:55 GMT -5
In mining of course......
Years ago, what always appeared to me to be an old electrician was really just a tad older than my late Dad, one thing he told me was " when you get a telephone call saying you have a breakdown, ask questions and see if you can get the job running that way" Next he said " when you're on the way to a breakdown you couldn't get running by phone, think on the move, fault find while walking, think of everything possible that could be the problem based on what you were told by phone"
I always remembered those words, sure the first part really doesn't apply too much with modern equipment, the feller who called me wasn't sophisticated..... so his knowledge would be very limited to basic questions....
Second part always helped me to minimize "downtime" And modern mines are costing big bucks while the belts are stopped..
I used to like taking a labourer with me to a breakdown, his mind worked in a different way, his electrical knowledge was very limited, so he'd catch simple things I missed..
I recall one night, I got called out of the mine when I was at British Gypsum, to the ore handling plant, everything was stood, I walked up the steep gantry to the screens at the top, asked some questions to the operator, then proceeded to open the control cubicle to carry out some tests.....Hmmmmm, this looked like being a long night!! I was running some continuity tests with my megger when the operator asked me what that loose wire I'd missed was for.....Voila!!!! He'd found the problem for me and saved a lot of time...
After replacing the wire in it's connector, I checked all connections for tightness....There was a lot of vibration up there when the screens were running.... Closed the door, powered up, pressed the start buttons and the plant came to life..
I was leading hand, (Chargehand) on nightshift, I was doing my rounds of my blokes seeing they had no problems, phonecall for me... One of my blokes was in bother and needed a second opinion. I arrived a short time later, and he said he'd been "going around and around in circles for over an hour and felt like a real dipstick for calling me" Nights aren't the best shifts for a clear mind for fault finding, we've all been there at one time or another and missed the obvious looking for a major problem that didn't exist.
"OK, I said" looking at the schematic, "Lets start there, the start button, and check for continuity between it and the next stage" after about ten minutes we'd found the problem, a broken wire he'd missed... Nothing wrong there, we have all been there and done that, I have "several Tee shirts" to prove I have....LOL
Another nightshift, another mine, my body was on auto, my mind was numb..... Just one shift I was having a job thinking clearly. Got a call to a main trunk belt, Huwood Mk1A control gear with a Master and Slave GEB's for the two belt motors, one GEB was a Wecol A69 and the slave an A67.
On the phone I asked does the belt start after the pre start alarm has stopped.......No was the answer, just goes to belt slip indication..... Well that was a start, sounds like a Mk1A problem, or a Master (A69) GEB problem.
First thing I did was drop the Master out of sequence to try it, started OK, same with slave GEB.
Everything into manual sequence, pressed the start button on the Mk1A, pre start alarm sounded, no belt start and the "belt slip indication" came on....Hmmmmm.
Opened the Mk1 up, checked for the obvious, nothing, used a couple of the "staple" shorting links to test sections of the relay circuits, and believe me, the Mk1A has a lot of relays in it!!!!
Still had the problem...Been going around chasing my own tail for nearly an hour....My mind just wasn't functioning that night.
Shift mining super was asking what was wrong...Yeah, if I knew that I'd have the job running.
There was a spare chassis in the workshops, I got my labourer to bring it down to me, swapped it out, made sure all shorting "staples" were in place in unused circuits, closed the door and tried again.....Nothing!! Jeeze what am I missing??? No faults were showing, all fault indication lamps were working, pre start alarm working, GEB's and pilot circuits were healthy........Then it hit me like a sledge hammer.....Pre start alarm monitor!!!...I opened the door of the Mk1A, dropped a short across it, closed the lid, and everything started........
I'd lost about two hours of production over something simple.
I got the old chassis back to the shop, picked up a new pre start alarm monitor and changed it out..First opportunity, during a belt stoppage, I removed the shorting link....Worked perfect.
So easy to miss the obvious on nights, glad I didn't screw up like that often!!
Day shift at Boulby, at the intersection of C3 and C4 belt was a Wecol A67 GEB for C3 drive, it was very hot at that point, and the Wecols we used had several electronic modules inside of them. I got a call that all the belts were stood and C4 wouldn't start, as it was the control room calling me, I couldn't get too much info, other than they couldn't get it to start......I already guessed the problem, E/L trip..
I got through the air doors at the back of the workshop, turned right at the top of the ore bins and I could see a red indicator from the front of the GEB as I approached it....That GEB used to get stinking hot, it was just hot a position to have so much electronics... I'd just started to open the door of the GEB when the Under Manager walked up wanting to know what was wrong, I pulled the control module, and said catch, he caught it, juggled it, believe me it was extremely hot!!
