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- From: Lawrence London <lfljvenaura@gmail.com>
- To: machinist@lists.ibiblio.org
- Subject: [machinist] How to better understand electronics?
- Date: Wed, 13 Nov 2013 22:40:31 -0500
http://www.practicalmachinist.com/vb/general/how-better-understand-electronics-274987/
Thread: How to better understand electronics?
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11-11-2013, 12:27 PM #1
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How to better understand electronics?
I've become fed up with being ignorant about electronics and practical electrical stuff. I can wire up a simple 3 ph. machine, install starters, did all the wiring in my first shop, but when it comes to more sophisticated stuff I feel intimidated.
For instance, I'd like to install remote controls for a vfd. I want to understand and be able to work with dc motors and controllers.
Are there any good books that explain these things for elderly dummies?
All suggestions welcome, even snarky ones. -
Buy your VFD from Automation Direct, get a GS2 of the right hp rating for your application. The book is very good, and simple. They also have helpful videos on their website
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IMHO what your after is more of a coarse on control and automation. The actual electrical theory side of it you can to a large degree just act pretty dump to and get away just fine. You realy don't need to know - understand phase angles and all the complications hat 3 phase electrics bring to the table, the VFD deals with all of it for you so long as you programme it correctly. Which is little more than just inputting the info of the motor rating plate into the VFD.
Remote controls are simple low voltage controls, most VFD manuals show what you need to know. Normally little more than a 47K ohm pot and a on off + direction switch all from outputs - inputs provided by the VFD. If you want more advanced - safety interlocks and such you have to look at how that effects the vfd - local legislation on safety guarding interlock requirements etc and that's the harder bit.
DC motors and controls are going the way of the dinasour to a ever larger degree due to brushed motor maintenance requirements. -
Buy an Ameter, a fluke 87. If it is beyond these, you are getting into design. I have learned all that I know working on cars and computers-it isn't much, but it gets you to the point of knowing what part is bad-which is ok with me. Some instances where I need to go deeper, I use the internet to find instructions, but this is normally for things that are mass produced, cell phones game systems and computers. Not much on machines outside of this forum.
Joe -
Navy Documents
Download the Navy Electricity and Electronics Training Series (NEETS). Scroll down on the link above to find NEETS.
If you read the series, you will be the go to guy for electricity and electronics.
You're not a dummy if you want to learn electricity and electronics. It's not hard to learn, but you need to understand the fundamentals to get a good grasp of the higher level concepts and practices.
Regards -
For electronics of simple circuits, I have found that "doing the math" really aids my understanding.
Originally Posted by richard newman
I've become fed up with being ignorant about electronics and practical electrical stuff. I can wire up a simple 3 ph. machine, install starters, did all the wiring in my first shop, but when it comes to more sophisticated stuff I feel intimidated.
For instance, I'd like to install remote controls for a vfd. I want to understand and be able to work with dc motors and controllers.
Are there any good books that explain these things for elderly dummies?
All suggestions welcome, even snarky ones.
To use your example of the VFD control, in particular the speed control pot. If you run the numbers on Voltage applied, through the Resistance , to determine the Amps passed and Watts consumed, You will leave the exercise with a good idea about what it would take if you wanted to automate the process with devices such as a plc or "mini controller". Or , even just a seperate voltage or current source.
Lots of learning there.
It takes one volt to push one amp through one ohm. And that one amp dissipated in one ohm at one volt consumes 1 watt. -
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Horowitz and Hill would be the textbook you are after. Some of it's pretty
high level but it covers the basics.
Art of Electronics: Paul Horowitz, Winfield Hill: 9780521231510: Amazon.com: Books -
11-11-2013, 09:10 PM #9
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I think, at this stage in the game, a fella could do worse than to head to Radio Shack or The Source, depending what they are calling it these days, and looking in to the basic electronics hobby type books.
Or the Public Library. Just the basics, what the various circuit diagram schematic symbols are, what they do, etc.
If you can follow a straight line through a diagram, you can wire up the switches and a potentiometer to control a VFD.
Cheers
Trev -
11-12-2013, 10:23 AM #10
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Thanks for all the suggestions.
I have downloaded the first module of the Navy course and put a hold on the Horowitz book at the library. Now to find the time to work through it all. -
11-12-2013, 04:12 PM #11
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Hi Richard, as stated earlier it all starts with the basics which are not that difficult to understand. If you don't have the basics then nothing else is going to make sense. Learn parallel and series, ohms law, a little about capacitance, a little about inductors, some transistor theory etc. Stay away from the somewhat mind boggling stuff and you will be okay. There is quite a bit of math involved but I think at the level you are seeking it is not high level math. Mostly just division,addition,subtraction etc. You don't get into the trig stuff until you delve into 3phase etc. Try to be satisfied with treating certain circuits as a "black box". With all the integrated circuits out there today there is no reason to get wound up in your skivvies worrying about how some chip works. Just learn how to interface it properly and you will be good to go. Most ICs (integrated circuits) have a lot of information on them and show how to interface them properly. There are usually some external simple components like resisters and capacitors in the provided diagrams. Designing is a whole different ball of wax but I don't think you want to go there from what you have said. Just learn the basic components and how they work and realize that most everything is built out of these. You might spend some time learning gates and flip flops and things too because again there are a lot of things that are just made out of a crap load of gates (nand,and, or, nor etc.) Flip flops are handy to know too. If you could learn how about 30 things work you would be way up on the learning curve. Good luck.
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You could do a whole lot worse than picking up any old (or new) ARRL Ham handbook. The front section of the Handbook is a crash course on electronics (albeit from a radio ham perspective) for people who might be coming into the hobby from all walks of life. The Handbook also covers electronics construction techniques, soldering, wiring, etc.
When I leaf through any ARRL handbook, as a now retired EE, I'm impressed by how well they explained stuff.
Let's put it this way: An old ARRL Handbook from the 1960's that was given to me as a kid was what enabled me, at the age of 12 in the mid-70's, to build my own radios, make my own antennas and learn tube and transistor circuit application and some theory... and teach me trig before I was 13.
Not too shabby for a book that had a price of $1.50 on its cover, I'd say.
Things that apply in CNC systems, like control system theory (which gets into circuits to control servos and the like in a moving system) - well, that's a whole 'nuther kettle of fish, the the ARRL Handbook doesn't address that at all.
Basic electronics, Ohm's law, reactance/impedance, AC circuits, etc - the ARRL Handbook does all that very well. The newer editions since the 1980's do a good job at introducing many simpler integrated circuits, like op-amps, power supply voltage regulators, filters, etc. Since the mid-80's, the Handbooks have done an OK intro to microprocessors as well.
AC motor theory, in detail, well, that's yet another area of electrical engineering that can get very deep, very fast. Basic 3-phase induction motors, which are used in most older manual machines however, are a very well explained area of AC motor theory for over 80 years now. You can find induction motor theory all over the place online. Once you have the basics of reactive power, impedance and complex math down, 3 phase induction motors become pretty straightforward. -
I am sorry to say this, but most- probably 90% from last shareholder report I read- are purely consumer electronics, in other words the same Ching Chong sh*t you'll find in Wal-Mart but rebadged with a Radio Shack Corp house brand name. Originally Posted by trevj
I think, at this stage in the game, a fella could do worse than to head to Radio Shack or The Source, depending what they are calling it these days, and looking in to the basic electronics hobby type books.
Or the Public Library. Just the basics, what the various circuit diagram schematic symbols are, what they do, etc.
If you can follow a straight line through a diagram, you can wire up the switches and a potentiometer to control a VFD.
Cheers
Trev
This started really badly in the 1990's and it was a done deal when they ceased operating as Tandy and became Radio Shack Corp. Sense then, they have been mismanaged altogether, it's pitiful.
I went into one not long ago and asked to by 500k ohm pot and a 500k resistor. The blank stares were amazing to me. No Ham or CB section anymore. Just what amounts to me to be: junk. -
I also suggest you visit your local RadioShack or electronics store and pick up some circuit components, resistors, capacitors, inductors, diodes, etc..., that you can plug them into an electronics breadboard and model the example circuits described to reinforce what you are reading in the Navy course. If you have a multimeter, you can measure the values. Reading with hands-on demos is the best and easiest way to learn. If something is not clear, use the Internet to get a different explanation of the concept or theory.
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11-12-2013, 05:51 PM #15
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More good advice, thank you all, I'm looking forward to getting into this stuff.
I should admit that I'm not all that ignorant actually. Did 2 years of engineering school in the early 60's before I got thrown out for cutting classes and spending all my time in the student union craft shop building banjos. I'm comfortable with trig, algebra and geometry. Have a multi-meter, can deal with basic Ohm's law stuff, after that I get shaky. -
11-13-2013, 04:23 PM #16
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I have long since given up on an intelligent response from the wage-monkeys behind the counter in most places like that, unless I have questions about cell phones or the like, I don't much bother to ask. Originally Posted by geardoc
I am sorry to say this, but most- probably 90% from last shareholder report I read- are purely consumer electronics, in other words the same Ching Chong sh*t you'll find in Wal-Mart but rebadged with a Radio Shack Corp house brand name.
This started really badly in the 1990's and it was a done deal when they ceased operating as Tandy and became Radio Shack Corp. Sense then, they have been mismanaged altogether, it's pitiful.
I went into one not long ago and asked to by 500k ohm pot and a 500k resistor. The blank stares were amazing to me. No Ham or CB section anymore. Just what amounts to me to be: junk.
They usually still have a small display of 'project' stuff at sometimes silly prices, but, available.
I recall getting some (I think) Radio Shack brand named Projects kits as Christmas presents, IIRC they had 60 in one, 90 in one, and 120 in one, projects with spring connectors and a variety of different color coded lengths of wire to join them up.
A Google search of Electronic Project Kit shows a bunch of similar are still available, and may be worth checking out. Kid stuff, maybe, but ya gotta start somewhere.
I was fortunate enough that there was a little bit of interest in some electronics stuff while I was in High school. We made and etched circuit boards, soldered up the components, etc. Not rocket science, and not really in depth into the theory side, but some hands-on, with an attainable end result.
Seems to be all about programming Arduino and that sort of stuff towards robotics, that is getting kids in to the stuff these days. Whatever it takes is good!
Cheers
Trev -
11-13-2013, 04:51 PM #17
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H&H is good but I find having a decent textbook reference essential. Don't let the title scare you, this book has all the fundamentals of components clearly described, along with the math. The latest edition is expensive but you don't need it. Here's a cheap one- Introductory Circuit Analysis by Robert L. Boylestad: Merrill Pub Co 9780023131615 7th - Better World Books
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11-13-2013, 09:21 PM #18
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When I wanted to learn about machining, I bought a high-school machine shop text and a lathe. Applying this same thing to your situation, I'd suggest buying a simple VFD, a small 3-phase motor and a few button switches and potentiometer. Read the Chinglesh manual and get it to work. It'll take some effort, but it's definitely not rocket surgery. Factorymation has all you'll need... Originally Posted by richard newman
...For instance, I'd like to install remote controls for a vfd. I want to understand and be able to work with dc motors and controllers...
Home - FactoryMation
After that, move on to DC motors and controls, if you want.
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- [machinist] How to better understand electronics?, Lawrence London, 11/13/2013
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