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My new book - any thoughts?
4

My new book - any thoughts?

My new book - any thoughts?

(OP)
This is a very general electronic, electricity and automation question.

I have in my fourty+ years as a commissioning engineer, trouble-shooter and designer with ABB, Siemens and own company found that there are a few very common mistakes that account for a vast majority of all problems in automation and drive systems.

I am going to sit down in southern France (Camargue) for a couple of months and compile 30 - 40 dominant causes for unexpected problems and badly functioning systems. It will be about inrush currents that takes out fuses/breakers and cause short contact life, unnecessary high band-width that makes systems unreliable, cooling and why it - contrary to popular belief - is good to have. There will be eternal but forgotten truths about many other things like bearing currents (that will be a long chapter), DC motor operation and thyristor drives and I will mostly use stuff that I have collected during field work. Each subject will get a two - seven pages (A4 - a little less than legal - format) treatment with four or five pages being typical.

I am, however, sure I will miss out a few important topics, I have, after all, not seen all problems (I think).

So, if you have any unusual, interesting or plain stupid things that you think should be included in the book, please add a few sentences here. Or e-mail me. Also, if anyone in southern France would like to have a Pastis with me, just say so. I could use some divertissement... (I do speak French, so language is not a problem. Especially not after a few 51 smile ).

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

You should include about 30% drinking tales, descriptions of interesting locations you've seen, fascinating characters, misadventures, and so forth. Make it a more entertaining book, not just pure technical descriptions.

I'll place my order for a signed copy now. Assuming it's not overly expensive. smile

RE: My new book - any thoughts?

Screw the expense, I just hope that I can comprehend the jargon. I've been talking to Sparkys a lot today and my brain is melting with the "sinking 5V inputs" and "looking for a trailing edge" of a signal. I was quite happy with the "flip the switch and the light comes on via magic" explanation. My brain isn't wired for this stuff.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"

RE: My new book - any thoughts?

"Environmentally Enhanced and Ethnically Correct Electrical Circuitry for Color Blind Dummies"?

Mike McCann
MMC Engineering

RE: My new book - any thoughts?

David, electrical circuits work just like water circuits, except the resistors are linear, so the math is easier.

winky smile

Mike Halloran
Pembroke Pines, FL, USA

RE: My new book - any thoughts?

(OP)
Mike

I may use that as an introductory remark - it says a lot. And sets the level...

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

Measurements and the techniques that work reliably in difficult conditions. Perhaps a second chapter on techniques and equipment that DOESN'T work and why. wink

RE: My new book - any thoughts?

Along with the measurement techniques - the use of high speed cameras in ballistics research might make a nice sub-chapter.

RE: My new book - any thoughts?

(OP)
Your memory sometimes serves you annoyingly well! smile

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

I've always wondered. When they teach electrical guys about circuits they always use plumbing and springs. Do they use electrical circuits to explain plumbing and springs to mechanical guys?

RE: My new book - any thoughts?

We use springs and pipes because they're easy to understand for beginners. Mechs choose to work with springs and pipes for similar reasons... tongue

RE: My new book - any thoughts?

Tu me fais jaloux!

Mark me down for a copy!
I think the world is full of "introductory" and "how-to" books, especially in this age of the internet which is miles wide and inches deep.
What we all lack is the benefit of experience and the stories that make us understand WHY.

Just a few of the strange problems I've encountered:
High-resistance terminal connections,
Sneak circuits keeping a circuit on when the switch is off,
Lack of strain relief,
Snow/ice bridging terminals,
Slow RC time constants,
The difference between the junction temperature on a semiconductor's datasheet and the real ambient temperature.

I've been the culprit often enough to stay humble and double-check before hitting the ON switch.

If there's anything you can write that fosters the reader's ability to TROUBLESHOOT anything it could tip the book from being a memoir to required reading in colleges.

Bonne chance

STF

RE: My new book - any thoughts?

(OP)
Merci!
I never thought of including the junction temperature and thermal resistance, although I certainly have had that also. Just didn't remember. That's the kind of input I am looking for.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

Did you ever have common mode on a control signal drive the signal offscale? But the differential measurement was OK?

RE: My new book - any thoughts?

I've seen a ty-rap installed tightly enough to short a twisted pair inside a shielded cable.

Mike Halloran
Pembroke Pines, FL, USA

RE: My new book - any thoughts?

(OP)
Yes, danw2. There will be a dedicated chapter on that. It will also include ground-referenced techniques allowing 4-20 mA measurement without breaking the loop and without inserting resistors or diodes. There, the common mode range is essential. You can, of course, use a DC current clamp. But if you need to measure more than one signal, it is usually not possible to find one single mA DC clamp. Let alone several.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

Would you consider a section or chapter on "Planning for Maintenance"?

I am constantly amazed by the number of sites and installations that are in need of cleaning, adjusting and testing that doesn't get done because "it can't be taken off line".

On automation, PLC's specifically, maybe why good documentation in the project is important. I get into a lot of programs that the original programmer probably had a very good idea what he was trying to do his head, but after several years and he is no longer available what would be good to leave behind to help the guy that is trying to help his customer and keep the system going? I'm not sure why but it seems to be worse lately.

Good Luck on your book, real world experience compiled into something others can use and learn from sounds like a neat project.

Thanks, Mike L.

RE: My new book - any thoughts?

I don't think this is nearly specific enough in its own right, but might form a recurring viewpoint for several issues: Understanding the difference between a useful approximation and an oversimplification - and how to recognise that boundary when you get to it.

Dominant causes for badly functioning systems? Not getting somebody to do an independent check of all your switch positions before deciding your equipment is broken - especially when picking and choosing sections from a longer set-to-work procedure. Catching this one by telephone today just saved us a 16,000 mile wasted round trip (I hope).

A.

RE: My new book - any thoughts?

Skogsgurra,

If I may share a bad experience that I once had about connecting 2 DC motors (900 hp each). Since the connection box was not so big, all power cables where pushed very close to eachother inside the connection box. To prevent friction damage between two cables or bewteen cables and ground, my boss (senior electrician) recommended to add some thick rubber pads between cables and between cables and ground.
One day, both motors had been revised by an external company and when we reconnected the motors, as usual we used thick rubber sheets to avoid ground contacts or short circuits.

As a final check we tested the insulation resistance and found that the value was somewhere arround 0,1 Megohm of both motors. When disconnecting the cables again, now the resistance of both motors and cables where ok. So reconnected both motors and again bad insulation resistance.

It turned out that the rubber pads where not the same as usual, although they seemed identical. The rubber sheets that where used contained graphite and were in fact excellent electrical conductors.

Since then I no longer thrust any kind of rubber as insulator smile

Kind regards,

WTRVS

RE: My new book - any thoughts?

Grounding in general seems to generate a lot of field issues. Both for power and instrumentation/control. If you could sort out the factual from the anecdotal myths, that would be a great service.

Also, some recommended troubleshooting techniques and methods - no one learns this in school.

RE: My new book - any thoughts?

Gunnar, I'm not sure if you were involved but there was a thread in here (that I can't find) about an excavation site in which the power supply was inadequate to start a third shovel when two were online. The solution was to raise the two online buckets and let them fall in order to generate a bit more power for the third shovel's start-up.

I thought that was a wonderful trick...

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

RE: My new book - any thoughts?

(OP)
Great comments trickling in!

I have thought about some type of structured "tree" to help in systematic trouble-shooting. And there are inputs that help me doing that.

And, I think that I shall include little factoids/ancedotes like Dave's falling buckets. That will make for lighter and more interesting reading. More such stuff!

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

That tail of falling buckets couldn't have come from anybody other than waross. I do have a vague memory of it. Bill??

RE: My new book - any thoughts?

Back in the seventies I worked on a the erection of a large dragline at the Syncrude project.
Some stats:
Mass; about 7000 tons
Power: 12,000 HP. 4 MG sets. Each set comprised of a 3000 HP motor driving three 1050 HP DC generators and two 1300 HP generators. Weight of each MG set, about 80 tons.
Working radius: 360 feet.
Height of boom above grade: 214 feet.
Length of boom 400 feet.
Drag bucket: about 75 or 80 cubic yards.
Power supply: 12,000 Volt trailing cable.
Watching the meters when this was working, the draw would be about 7 MW when the bucket was being lifted. Dropping the empty bucket would regenerate about 2 MW.

We had ample power to start the machine. We had an adviser from Bucyrus-Erie on-site. While sharing a coffee break, he told us of the technique that was used in strip mines with a soft power supply of using the regenerated power from the dropping buckets of several machines to ease the starting surge of an incoming machine.

This machine is now out of service and on display beside highway 63 near The Syncrude base plant.
http://farm1.static.flickr.com/87/225535786_51a81623a9_m.jpg
http://media.jrn.com/images/oilsands-21-oilsands-syncrude-at-dusk.jpg

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: My new book - any thoughts?

(OP)
Bill - of course!

That is a wonderful story! The 'puter paralyzed need to hear such things! I guess there is even som math they can do on this. The pictures, the way out and the math. That is something the youngsters will love.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

Some may notice that we still have over 5700 HP of generators on a 3000 HP motor.
The operating cycle was such that the generators were never simultaneously loaded to their maximum capacity.

The generators had Babbitt bearings lubricated with oil rings. There was no turning gear. Once running these machines typically run 24/7 indefinitely. During test and commissioning, each night, we had to manually "roll" each set until the oil rings had brought enough oil up so that the set turned freely. We started them with two men on a seven foot hook wrench on a coupling and two more to reposition the wrench each time it was lifted for another bite. We usually had four to six men working together to roll each of the four sets. When four men could keep the set turning easily by pushing on the ends of the armature windings we were ready to go DOL and then move on to the next set.


Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: My new book - any thoughts?

My ideas are less about the technical aspects than as a book. If it can/ment be used as a reference I would say make sure it has a good table of contents, a good index, and at least a basic definitions section. I have several different reference books that have great information, but they lack in the above items, making it very difficult to locate the information.

RE: My new book - any thoughts?

(OP)
Great! I had been thinking of a TOC. But it is easy to include an index also. And the definitions part - I made one for SKF a long, long time ago. Perhaps time to refresh it.
http://www.google.se/url?sa=t&rct=j&q=&...

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

(OP)
OOPS - that's the wrong version! It contains spelling errors and also a numerical error. So don't pay too much attention to it. Of course, a definitions section would be nice. But that would be either monstrous or incomplete. So, I think that I will add 'intratextual' definitions where needed. The index could then be used to look those definitions up.

Remember, it will not be a text-book on automation. There are many good ones already. The book will cover things that never get mentioned in text-books, but still will meet the engineer once he is 'on the loose'.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

The book is sounding awesome. The inline definitions with index would work well. I may not deal with automation as a job, but I do need to know those kinds of things to help our customers. I am definitely interested in getting it once you finish it.

RE: My new book - any thoughts?

(OP)
BTW, the book will be in Swedish. At least initially. So it may not be very useful to the engineering community in a broader meaning.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: My new book - any thoughts?

I answered a call to a small crane with the complaint that the hoist brake would not release.
The brake coil was controlled by a relay similar (but not identical) to this:
http://www.cesco.com/b2c/product/224599
The machine had been in service for several years but for some reason the relay did not interrupt the current. The brake coil was a fairly high resistance and the current was quite low but it set up an arc across each break of the double break contacts. The heat was just enough to melt the silver alloy contact material. The molten material then flowed together in such a way as to bridge the contacts. Once there was a metallic path and no arc the metal cooled and left the contacts welded together by two miniature hour glasses of silver alloy.

Bill
--------------------
"Why not the best?"
Jimmy Carter

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