Voltage in a DC generator

simple to speak,

they all work under meganetic field action. motor was pushed by megnatic, and genertor cut magnetic line by outside machine to generate electric.

KWNish;

Well Nish, it would be a waste of my time and a great disservice to you to attempt to give you a background in rotary induction machines. It would be like the blind leading the blind. But I have a very rough understanding of what your asking so here goes.

A great investment, if you have not already made it, are some introductory text books in physics. Preferably books that are written as introductory texts for the engineering and science fields. Go visit a a university town with an engineering school and go to the bookstore that supplies the textbooks. Be prepared to spend some money, but once that money is spent, it should last you a life time. The laws of physics don't change much. Any introductory text should give you a brief introduction to magnetic induction. And there is lot on the net for free.

Also, if you can afford it, buy a copy of the CRC Physics and Chemistry Manual. It is a huge book, but it covers a very broad range of disciplines. It is another resource that will last you a lifetime.

Another great book, one of my favorite quick reference books, is "Dictionary of Science S I" Uvanrov, Chapman, and Issacs ISBN 014051.001 x. I don't believe this book is in print anymore, but there are still copies available out there.

Round your little library off with some text books from some technical electronics schools.

The questions you are asking are very fundamental, as such I would recommend that you follow your curiosity and imagination and expand your horizons by spending a little money and get yourself some basic background in what it is your interested in. Formal education is ALWAYS the track most likely to give you a sound background, but sometimes that is not always possible. What it will take in any case is dedicated time.

A brief answer to your questions.

Yes, a motor can be circuited as a generator, and vise versa, this is the basis of electrical regenerative and dynamic braking in electric traction locomotives AND the modern Hybrid Automobile. Here is a link that might help you. If you can get by the Title and first paragraph. You might find that part dealing with Regenerative Braking helpful.

http://www.bestsyndication.com/Articles/2006/c/carter_mark/031206_hybrid_cars.htm

The question you have on induced voltage has several variables. In terms of the physical design. The number of turns of wire on the coils will affect the output voltage. Once the device is designed and built the voltage can be varied in a number of ways. We can increase the rotation rate of our generator which increased the velocity that our coils cut the magnetic field lines, or increase the the strength of our excitation field by increasing the voltage applied to the excitation coils. The current flowing in the circuit will be a function of the load circuit impedance. In any case, the work done by your generator will approximate the torque times angular displacement less the efficiency losses. The linear equivalent is Force times displacement. The power is the Work/time. At constant RPM and constant voltage, as the "load" increases it will require more torque to operate the generator.

Motors and Generators are quite efficient, I believe better than 90 percent. Using 90% as our efficiency; this would mean that .9Τω ≈ Volts * Current = Power.

DC generators require commutation, as do DC motors, that is why it is often more practical use alternators (AC generators) and then rectify to DC if indeed DC is required for the application. There are of course exceptions, Electrodynamic Braking in Space Applications being of most recent personal interest. Page down to the subtitle - Electro-Dynamic Braking at

http://www.bestsyndication.com/?q=072407_solar-power-sailing-in-outer-space-extend-long-distance-travel.htm

Since I was working from memory, I hope I didn't error. If I did, your introductory physics text will set you straight.

Gavilan

Thank you kindly

Your post is both interesting and informative. I will take you advice and pick up a few of the listed texts, depending on price of course. Hopefully I can find the time necessary to studying them. I also believe that the two most important keys to learning anything, are interest and time. Time being most often the rarest of commodities. On the other hand, time can be created through dedication, and dedication is controled by interest.

The only difference when running a DC machine as generator and Motor is the location of the brushes as the neutral axis shifts by the same degree forward or backward and brushes are to be set Properly to have good commutation.A very good understanding of the machine running as a generator and motor can be obtained by revering To Electrical machines by Fitzgerald and Kingsley which consider as bible for electrical machines.As regards design any good hand book or design text book will give details on DC machine design.Wish u all the best in your research.

You have correctly mentioned a very important point that 99% of the amateurs completely overlook when discussing the differences between DC motors and Generators, thanks for mentioning it so clearly.

Old-fashioned brush-type DC generators are essentially the same as old-fashioned brush-type DC motors. There are three basic varieties of each, viz. series-wound, parallel-wound, and compound wound. DC generators are either self-excited or externally excited. The power they produce depends on many different factors, such as armature wire size, rotational speed, field strength, etc. A good elementary text on electricity in general, with an easy-to-understand section devoted to motors and generators is Harry Mileaf's Electricity 1-7. It isn't the only good reference, but it is brilliant in its simplicity.

Hello KWNish

This is big topic to describe in detail , but you can start with basic designs , knowing motors , generators ,electromagnetics to rudementry level will creat interest for further explorations .Motors & generators are identical in built and designs but there rated specs for power delivery , RPM ,Torque ,make them little different , say for example you can run a motor with supplied electricity for desired RPM , vice versa you can rotate motor through external means and generate electricity but not exactly you would expect to get , but through generators you would get desired ratings for same RPM , you can have a prilimary study on automobile electricals specially alternators

If you wind more wire you get more voltage , less amperage , less but thick wire more amperage , but less voltage , you can have a look at this site it is quiet interesting www.windstuffnow.com and likely to answer your questions

There are plenty of websites where you can get the info you seek. I've got a good list of them on my Gateway Laptop that shut down on me unexpectedly last week, & won't turn on anymore. (Happen to anyone else?) If I get to that info I'll let you know.

Check: Universities Engineering School's sites, "Institute of Physics", "Hyperphysics", Livescience.com, "ScienceEncyclopedia", "Physics Help".

Good Luck