Joatmon

Xittenn, there is a lot of sense in what you say. Perhaps, even probably, I have been rather arrogant about this issue. I do feel very confident about my assertions because basic machine theory hardly changes with time and it was my job to lecture on this particular topic to several classes a year for ten years. By the way I did not really want to have you identified! I accept that in a forum such as this a less blunt and dogmatic approach is the best way to work harmoniously. Can't we be friends?

It seems the irony of my post has not been detected. I don't actually accept the suggestion that I am mentally "over the hill" and need retraining! In fact, after a burst of indignation I could see the funny side of such a suggestion. But perhaps timo and ajb are doing a sort of joke by pretending to take my post seriously? Perhaps I should apologise. In the meantime I see in the small ads someone is looking for a rocking chair tester so if you will excuse me.......

We shall just have to leave it at that then. My final say is that the maths is very simple and in accordance with the attachment. The formula does not need coil inductance or reactance - only the number of turns and rate of change of flux. I'm sad that this exchange got so acrimonious.

I tried to give you this as a personal message, but since I have been barred it has to be public. I'll give you full marks for perseverance. However, although I don't want to upset you, I will try to tell you what I see as the broken link in your analysis. In step 1 you find the inductance of the solenoid, that's ok. In step 2 you must be forcing dc current through the coil so it produces the steady magnetic field of the magnet. I don't see this as useful to your analysis. In steps 3, 4 and 5 you do a good job of analysing how this solenoid will behave as (say) used as a load at the frequency you have set. Now we come to the problem as I see it. The OP wants to know how much V he will get when he passes the magnet through the coil. It may be very little if the magnet moves slowly or be considerably greater if the magnet moves quickly. I don't see how you can give him this information from your analysis. Furthermore, the coil will generate voltage, current flowing is dependent on any load connected to the solenoid. There isn't a constant V/I relationship independent of the load. As I have said - to me this is just a discussion between two people about a technical matter and I have never seen it as personal. Jo.

It has been suggested to me that my technical knowledge is no longer at a standard where I can sustain a debate or argument. It was suggested that I retrain. However, I retired almost 20 years ago so that really isn't an option. It got me wondering what I might do with very little training and fading knowledge. I am looking for suggestions. The best that I can come up with myself would be "pole dancer costume adjuster". However the remuneration would have to be very small otherwise I could not afford to take the job! So any ideas? All offers and suggestions considered!

This is a quote from an earlier, similar, topic made by TonyMcC. "Let us consider for a moment the possibility that our life is a test to see if we are suitable for some reward. Let us also accept that the person or being setting the test has the qualities that are being sought in us e.g. kindness, fairness, love of others etc. Let us assume that the person or being setting the test is all powerful and can do anything. Can we be tested for our attitude to things like suffering, unfairness in life such as the death of infants etc. without such experiences actually happening ? Well, one solution to this problem is that I am in a simulator and everything I have "experienced" is not at all real. Perhaps the rest of you do not exist and any response to this post will have been generated using artificial intelligence in a program within a computer that is more powerful than I am presently allowed to consider possible. Just a thought! "

Often talking out of your a**e can be more effective than talking out of your mouth!

If you are Christian just enjoy "as is". If not, then ignore the references to God and just enjoy the images, the sentiments and beautiful melody.

This does not help in any way with predicting the generator output. The B-field is a steady phenomenon and you suggest that driving current through the coil to produce the same B-field as the magnet will some how predict the generator output characteristics. You seem to suggest that the voltage connected to the coil and the current flowing through it will be the same as the voltage and current produced by the generator. This is (IMO) just not so. For instance the voltage coming out of the generator will depend on the speed of the magnet relative to the coil. How is this brought into your reasoning? Also when the coil is open circuit with no current flowing through it you will generate e.m.f. with no current. There are other problems that become apparent when you consider the effect of coil number of turns - I will explain these to you if you need.

Some people learn from their mistakes And some people don't. Some people seek and take advice And some people won't. There's none so blind as will not see The writing on the wall. They stumble blindly through their lives And wonder why they fall.

I don't want to get into an argument but calculating the reactance of his coil and using current/voltage relationships for the coil will not help him estimate the expected output of his generator.

I have to ask - answer to which question?

You don't need to consider the inductance of the coil. (or its reactance). Consider a single loop with a magnet passing through it. An e.m.f. will be generated in the loop. The amount of e.m.f. generated will depend on the relative movement between magnet and coil. i.e. the rate of change of the flux linkage. Now consider a coil with many turns. e.m.f.'s will be generated in each loop and they will act in series with each other and thus add together. http://hyperphysics....ric/farlaw.html

I wonder how many men are going to have a quick look at your profile now. Been there, done that, got the T shirt!

So is 69 itself (or so I have been told!). No need to complicate things. Loose writing - sorry lol. Of course I was thinking integers.

A couple of points I would mention. Xittenn's formulae above are not applicable to the generation of electricity. They refer to the opposition to current flow presented by a pure inductor connected to an external source of alternating voltage. (or voltage across a pure inductor when alternating current flows through it). The generation of voltage (e.m.f.) within the coil is dependant on the rate of change of magnetic flux and the number of turns the coil has. Note that this voltage is present (in fact at a maximum) when no current flows. So speed of movement , magnetic field strength, number of turns and length of the coil all come into it. Now for some practical advice - Multimeters have a large range of scales. The safest way to ensure you don't damage the meter is to start with the largest scale and then work your way down through the ranges until you get a sensible reading. Just in case I forget, I always set my multimeter to the highest voltage scale when I have finished using it. I think your idea of making it and seeing what comes out should be good fun - best of luck!

One for the dreamers! Sweet dreams! http://www.youtube.com/watch?v=q5y8TtUSC5c

This seems like a variation of the Monty Hall problem as discussed recently in the topic "Why is the Monty Hall Problem so controversial". I think that by swapping you increase your chances to 2:3. If you originally chose the box with money in it and swap you must lose. If you pick a box with nothing in it you must win.( assuming the other empty box is removed) You will pick an empty box twice as often as the box containing money. So you will win two times out of three if you swap.

Sad to say, when you are 74 its more about remembering! What happened to suspender belts and fancy stocking tops?

Does the extra energy gained come from a minute slowing down of the planet? ( the link "here" isn't available so perhaps it covers my question)

Both you and I are old enough to have survived the end of the world several times. I expect we shall survive this one!

Two things - first you went past death which surely means that in your dream you died, but you are still alive! Secondly, yes if you actually DIE when dreaming you will be asleep at the time. Much the same as if you actually DIE when awake you won't be asleep!

This is from another post of mine. It could possibly be a focal point, or might be something worth researching? (Note: you can "continue to site " without signing up.) "Apparently the development of cancer is very similar to embryonic development . I wonder if it is part of the cost of evolution. Perhaps if cells were never able to reproduce under uncontrolled conditions there would never have existed the possibility of controlled reproduction? ">http://www.scientifi...es-from-embryos"

Later - just had another look and I now have the diagram - anyone know why I lost it earlier?