1. Jul 16, 2013

### John231

Hello guys, I have a few questions to ask and I really need an answer for them all. Firstly, I know that the Dynamo or the Generator produces electricity to the vehicle engines and houses, etc... But I seriously wanna know how Dynamos produce electricity exactly. I didn't understood exactly how magnetic field inside a dynamo produces electric impulses or electricity. I wanna know what is the relationship between the production of electricity and magnetic field. And whether the electricity can be produced if there was no magnetic field in a dynamo. So look at these other questions:

Q: Do we use "oil" for power plants to produce electricity? If so, how? And I don't know what people mean when they say "steam" moves the windmill or blades bla bla bla...

Q: If the battery of the car switched on a Dynamo, can we remove the battery of the car before switching it off and drive the car via a dynamo only?

Q:

2. Jul 16, 2013

### John231

Q: When the dynamo is switched on, it produces electricity automatically without the need of a battery? Because I recently saw some videos of people manually produce electricity by dynamos via their Kinetic Energy. So what's the difference?
Thanks!

3. Jul 16, 2013

### SteamKing

Staff Emeritus
4. Jul 16, 2013

### Staff: Mentor

At the simplest level, moving an electrical conductor through a magnetic field creates a current flow in the conductor. (This is a huge oversimplification, but it's good enough to get you started). Thus, a dynamo and similar devices that generate electricity work by using mechanical energy to move magnets and conductors (typically by mounting them on a spinning shaft).

Burn the oil to boil water and make steam, use the steam to drive a steam turbine (google for "steam turbine"), use the steam turbine to spin the electrical generator/dynamo to make electricity.

You cannot, but it's not because the dynamo isn't capable of making enough electricity flow, it's because standard auto electrical systems expect the battery to be there to help smooth out any voltage fluctuations in the output of the dynamo.

5. Jul 16, 2013

### John231

You mean by "smooth out any voltage" is to prevent dangerous voltages coming out from the output of a dynamo?
Ok, but how will it not work without a battery? The Dirt bikes already work without batteries if they had a "kick starter" that start the dynamo with mechanical energy as I think.

6. Jul 16, 2013

### John231

*** And does a dynamo in a power plant works without batteries? If so why? Why does a dynamo in PP works without batteries and cars do?

7. Jul 16, 2013

### John231

Or the Oil and other resources like Nuclear reactors are used instead of batteries in Power plants?

8. Jul 16, 2013

### Staff: Mentor

Not dangerous to people, but dangerous to the car's electrical system - this thread from BITOG covers most of the ground: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1983065

Yes, as do lawnmowers and many other small-engine devices. It doesn't take terribly sophisticated electronics or precise voltage control just to operate a spark plug, and an older pre-electronics-era car will probably run OK without a battery. But a modern car all loaded with computers to drive the fuel injection, time the sparks, work the ABS brakes... Not so much.

9. Jul 16, 2013

### John231

*** And does a dynamo in a power plant works without batteries? If so why? Why does a dynamo in PP works without batteries and cars do?

Sorry for asking too much but you really make me understand how dynamos are working.
Thanks!

10. Jul 17, 2013

### Staff: Mentor

A battery doesn't produce electricity, it just stores electricity. And because a car's engine doesn't produce mechanical energy at a consistent rate, the alternator doesn't produce electrical energy at a consistent rate, so it is useful to have the battery to store the energy to prevent spikes. But that has nothing at all to do with whether a battery is required for the generator to produce energy - it isn't.

11. Jul 17, 2013

### ZapperZ

Staff Emeritus
I think you have a more fundamental issue here. I'm going to direct you to a principle known as Faraday's Law, where a changing magnetic field can induce a current in a wire.

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html

Make the connection to the fact that a dynamo has a magnet, and a coil of wire surrounding it, and one of them has to be moving to produce current.

Zz.

12. Jul 18, 2013

### sophiecentaur

Can I go back to basics, because you are still asking the same question? A dynamo uses a magnetic field and this can be produced with a permanent magnet or an electromagnet. An electrical voltage in a coil is induced (produced) when the magnet rotates (moves) relative to the coil. The elecrical energy comes from whatever is providing the turning motion, (you don't get anything for nothing) such as a wind turbine, steam turbine, hamster wheel. Most 'dynamos', these days are actually Alternators and produce AC, which may be rectified (as in cars) or used directly (as in AC Power Plants).
Simple alternators use a permanent magnet but bigger alternators (in power stations or in cars) use an electromagnet because it is easier to regulate the output voltage to suit the demand (how many devices are switched in). The energy for an electromagnet (or rather the Power needed) is not much and, before the alternator is turned up to speed, it is supplied from an external source, a battery, or, in the case of a massive power plant, it can be a 'donkey generator' (which is a small, additional generator and which may, itself have a battery). The system has to be able to pull itself up by its own bootstraps.
Once the alternator is up to speed, it supplies current to charge the battery, to produce its own magnetic field AND to supply the load it's there to supply.

13. Jul 19, 2013

### John231

Hello, thanks for your informative beneficial answer! But I wonder do "fully Electric-powered Vehicles" have dynamos to charge their batteries? And if they do, there will be no more wall-charging?? Or it will only charge for only some miles/kilometers?
Thank you!

14. Jul 19, 2013

### sophiecentaur

No. That would be a nonsense. The Energy has to come from somewhere. What would a Dynamo achieve if it were powered by the vehicle batteries? You always have to put more energy in than you get out of anything. You would, effectively, just waste some of the energy stored, originally, in the batteries.
You have to have "wall charging" or an alternative source of power (an internal combustion engine, usually), which consumes Fuel.
What you are suggesting is a Perpetual Motion Machine, which my Grandfather embarrassed me by proposing when I was at school in the late 50s. He also was surprised, later, that we couldn't hear the 'Satelloon' when it went overhead - (look it up). Old geysers let you down so often!!!!

15. Jul 19, 2013

### HallsofIvy

It is interesting that in Jules Verne's novel "Twenty Thousant Leagues Under The Sea", the Nautilus is run on batteries but nothing is ever said about how the batteries are charged! Verne himself seemed to think that batteries created power (or perhaps he just couldn't figure out how to reasonably charge them and just ignored the question). It was only in the "Disney Version" that there was the implication that nuclear power on a secret island was used- which led to the first nuclear submarine being named the "Nautilus"!

16. Jul 19, 2013

### John231

Sorry for asking too much, you know that Dirt bikes (internal combustion engine) which have a "kick starter" start engine without batteries. And cars (internal combustion engine) usually have batteries. So... What's the job of "Fuel" or "Petroleum" in cars? I'm really curious and interested to this topic! What I guess about "internal combustion engines cars" is that: when you start up the car, the battery has to produce the stored electricity in it to power the dynamo and the dynamo powers the engine so that the combustion process is applied; then "FUEL" will react very highly by compressing it, so that to produce to the dynamo "Mechanical Energy" to power the dynamo. Like the Power plants use Oil to be burnt to boil water to create steam to move the turbines... Is that right? If I'm wrong correct me if you don't mind and thank you for sharing your answer!