if you have one wheel driving and three wheels free rolling you cannot draw power from those three free rolling wheels as you drive the fourth because that would slow the vehicle and cause more power to be needed by the driving wheel.

If you are braking, you can use generators on all wheels to cause drag and make electricity to charge the battery. They call this regenerative braking.

Most electric cars drive 2 or all 4 wheels and use regenerative braking for most braking. They are required by law to have conventional brakes if more braking force is needed than the regenerative braking can provide, as you would need for locked (or near locked ABS type) wheel braking

Oh no, not another perpetual motion discussion! I come millions of miles and 300 years into the past, and people are talking about this and calling names? In the future we keep the name calling for aliens (Klingons, Borg, etc).

A generator will work in an electric car.The only thing is ,in todays market they are powering the generator with a gas engine. Defeats the purpose of the electric car in the first place.Some smart shade tree mechanic some where will come up with a charging system not relying on gas sooner or later. You are asking the wrong crowd here, these are engineers and they have been told "It can't be done" and who are they to argue it.

Has it not been done with the compressed air engine, from the workshop next to the blind barbers tree?

Hi hilltopper,

"You are asking the wrong crowd here, these are engineers and they have been told "It can't be done" and who are they to argue it. "

I am afraid you couldn't be further from the truth. Yes we have been told it can't be done but we are also smart enough and have the mathematical prowess and intellect to be able to calculate and prove that it can't be done.

Engineering is all about analyzing a problem and then though the use of applied mathematics, developing and designing a solution that will work. Ask yourself who you would believe, a guy in a shed with no experience or idea what he is doing, or several million engineers, that have built everything from a screw to the space shuttle and who have a fairly detailed understanding of the problem.

You can go off and waste your time, effort and money on a fools errand and I will help you along the way, however, in the end it is still a fools errand and you will look very foolish when all the engineers you scoffed at all say "We told you it wouldn't work".

Hi Masu,

I agree that perpetual motion is mathematically and scientifically impossible (at least on this planet). But I disagree that any guy in a shed has "no experience or idea what he is doing".

There are a few engineers and designers who have started out in sheds, and done what everyone else said was impossible (Apple 1).

I agree that perpetual motion is mathematically and scientifically impossible (at least on this planet).

It doesn't matter where you are in this universe to the best of our knowledge and there is no reason to think otherwise, the law of conservation of energy/matter applies everywhere.

There are a few engineers and designers who have started out in sheds, and done what everyone else said was impossible (Apple 1).

Very true, there have been some fantastic engineering breakthroughs made by engineers in their sheds. However, what I was trying to get across was that the people that are claiming to have constructed over unity machines are basing their claims of poor and incomplete scientific knowledge. I get annoyed when somebody that has no qualifications, tells me that I don't know what I am doing and that everything that I have worked on throughout my entire engineering life, is based on flawed knowledge and that I didn't know what I was doing.

However, I do believe that learning why these over unity machines don't work is a good learning experience and have no qualms of spending however long it takes to show somebody that is willing to learn why they do not work. When you however prove categorically that somebody has got it wrong and they steadfastly insist that all the engineers in the world are wrong and they are correct I get somewhat frustrated.

My avatar was originally red but after several weeks of talking till I was blue in the face on an energy from nothing thread it turned blue in protest. That particular person absolutely insisted that we all had it wrong and insisted that he was going to build his machine and show us all wrong. As expected, nobody has heard anything since so all I can say is, "We told you it wouldn't work".

"there is no reason to think otherwise"

Not yet, at least.

The last "over unity" machine I read about had allegedly been taken by "government agents". It involved using pulses of electricity to separate water, so the hydrogen could be burnt and used for electrical production. It appeared to produce more as an end result than what went in - but no measurements of quantities of input/output water were given.

As the "invention" was (allegedly) taken before the announcement of the test results, I can think of two possible scenarios: either it never existed, or it produced some radioactive byproducts which could be detected from a distance - with the right equipment, of course - something that the home user would not have, or think about needing.

Oh dear.... another one!!

Some people when told that a substance is poisonous and lethal if a handful is eaten, by many doctors, books and the internet...

Somehow they still manage to find a tiny little website somewhere that says its actually healthy to eat it, and so they eat it...

Later on their death beds they still insist that it must have been contaminated stuff!!

R.I.P.

ZZZzzzzzzzzz, I wonder how much drag he set on the reel 'cause he got you hook line and sinker Masu 'ol son. Have fun with it. Nobody's had a good go at Jorrie's "Garbage in Gigawatts out" thread yet though.

Oh by the way, there are a couple of professional trolls floating about various sites including CR4, the bloke that posts an enquiry for a 12 to 20 MW DC generator is one, maybe the original poster of this thread is one too.

Oliver, the motors used to drive the wheels become generators if the power to them is shut off and they are DC motors. This can also be used for braking, and both of these things have been covered by Aurizon.

It is interesting to note that for many years electrically-powered (lead-acid battery) industrial trucks have been used, and the wheel motors were always DC units. This is no longer true, as most industrial truck builders are now converting the battery-suppled DC to three-phase AC and using this to power wheel motors that are now three-phase AC by design. This method has improved the efficiency of these trucks in regards to power consumption.

But, these motors were never used for regenerative braking, and mechanical brakes were always used. A good example of using DC to drive a vehicle and brake a vehicle is seen everyday in the Diesel/electric locomotives used to pull rail cars. Under power, the Diesel engine is used to generate DC power to the wheel motors, and under braking, the power supply is cut off and the motors become generators. The electrical power produced by the generators (motors) is fed to a large grid that is on top of the locomotive, and this loads the generators (motors) and causes the locomotive to slow. Of course the Westinghouse air brake is required for the final hard stopping motion.

Ing. Robert Forbus

Just to bring things up to date. Off Highway Vehicles are now produced in both AC and DC traction versions with AC being fitted to the latest and largest. The 3 phase induction motor is quite effective at regenerative braking and is definitely used in this way. Simply put when the inverter output frequency is slowed below the frequency being regenerated by the motor, slip frequency is created and energy returned to the DC link via diodes. This energy is burnt off in retard resistor grids the same as DC traction. Presently the grid blower assemblies are a carry over from DC machines with the modification of a shaft earthing brush to protect the bearings. Battery powered machines can easily enough regenerate from squirell cage motors into the batteries during retard, for instance TZero and Tesla cars.

Many years ago, London Underground developed a thing called the 'Metadyne' braking system. The principle is to connect the traction motors in such a way that one of the motors was acting as a generator, using up the train's kinetic energy and converting it into electricity, with another traction motor arranged so that it was motoring opposite to the direction of travel, i.e. one puts power onto the motor to stop it spinning backwards and encourage it to spin the other way, thereby decelerating the train. Control over this brake is provided by connecting the generator-motor arrangement with a variable resistance in between, the rate of deceleration being related to the inverse of the resistance applied.

Such a brake is theoretically capable of decelerating a train at the maximum possible rate allowed for by the friction between wheel and rail, with the added feature that if one wheeleset begins to slip, the power dissipated in the system is reduced to the point where the slip stops, a valuable intrinsic safety feature.

London_Underground_O_Stock was originally fitted with this brake, among others.

The Metadyne was reportedly so good that drivers were instructed not to use it, as rough use would have entailed their impaling their nose on the other cab controls and any standing passengers ending up like sardines on the rear of the front bulkhead in each vehicle...

Nowadays, regenerating, electropneumatic and pulse-code-modulating brake systems are used as standard on LU stock, with the air-only Westinghouse system being used as a last-ditch device: LU drivers are instructed to use the Westinghouse at the last-but-one stop before a terminus, so as to satisfy themselves that it does work lest they should be called upon to rely upon it at the last minute in an emergency. Since the Moorgate_tube_crash other systems are in place also, arranged so as to prevent a train accelerating towards a fixed buffer stop as may be found at a terminus, particularly one located at the end of a single-ended tunnel; the system is known as the 'Moorgate Control' and a fuller description can be found in the above link.

Dynamic braking powering plug braking, thanks for the info.

hello

the generator needs mechanical energy 2 generate electrical energy. wr as a motor needs electrical energy 2 give out mechanical energy. a car runs, means it is doing some mechanical work. so we want the motor set 2 operate it. but not the generator.

ok if u use gen. then, 4m wr willl u give it the mechanical energy?

so we cant drive a vehicle (electrical) with a generator

regards,

priyanka

Hello Priyanka,

would be nice to get no cryptical posts - the milliseconds you save when writing in this way are wasted as hours when thousands of interested people are thwarted reding this.
Thank you.

Prynk, f y prsst n dng ths, w wll lmnt vwls whn w spk wth y

http://en.wikipedia.org/wiki/London_Underground_O_Stock

Hi Oliver,

Welcome to CR4, it's a great forum and I am sure you will both enjoy and learn from being involved. Don't worry about the derogatory comments, it often takes a great courage to ask what others see as a dumb question. Personally I believe not asking a dumb question is far worse than asking it, the only dumb question is the one that isn't asked. If you are worried about asking a question in a public forum you can ask any of the CR4 members privately. Just click on their name in any thread and follow the send XXX a message link.

Getting back to your question, everything aurizon stated is correct. It all comes back to the most fundamental law of physics which is the law of conservation on energy. The law of conservation of energy states that energy can neither be destroyed or created. It means that and energy that you use to drive something must come from somewhere and must go somewhere else when you stop it.

What happens with a generator is that you can't just drive it from something that is freewheeling, it requires s considerable force to rotate it. The more energy that is created by a generator the harder it is to turn.

A similar thing happens with an electric motor, the harder you try and stop it from rotating the more power it will draw. A generator is really and electric motor just being rotated by an external force rather than doing the rotating.

Now lets get back to what happens when you use an electric motor to drive a generator. Lets suppose that we have a setup of a motor driving a generator that is rotating but as yet not generating any power. If we start to use the generator to supply power to something it becomes harder to turn and makes it harder for the electric motor to keep turning. As we know the harder an electric motor need to work to turn something the more power it draws. In a perfect system where there is no friction or electrical resistance the amount of extra power the electric motor draws will be equal to the power the generator is supplying.

In reality however, there is friction and resistance so motors and generators only work at around 80% efficiency at best. This means that at the motor shaft you only get 80% of the power that the motor consumes and at the output of the generator you only get 80% of the power that is needed to rotate it. 80% of 80% is 64% so with a motor driving a generator the power output of the generator will only be about 64% of the power that is consumed by the electric motor driving it.

Something to note however is, as aurizon stated, you can use the electric motors in an electric car as generators when you are trying to stop. As you know the more power you draw from a generator the harder it is to turn and you can use this resistance to turning to slow the vehicle down. By doing this you can get back a portion of the energy that you use to accelerate the vehicle from a standing start. However, as we have seen, you can never get all of it back and in reality you are lucky to get much more than half the energy that was consumed when you accelerated from a standstill.

You may have noticed I have used the terms energy and power. Power is actually the rate ate which you are consuming energ. An analogy in a petrol driven vehicle would be power is the rate at which you are using the petrol while energy is the total amount of petrol you have used. With the Standards International system Watts are the measure of power and Joules are the measure of energy. If you draw one watt or power for one second you have consumed one joule of energy.

Well that's about it, it all comes down to the law of conservation of energy and the fact that you can never get back more energy than you put into a system.

Thanks for the welcome, Masu. And thanks for the explanation Masu and aurizon.

As I mentioned, I am not an engineer but I am a firm believer in going to (and trusting) those who have dedicated their lives to learning and understanding the answers to the kinds of questions I asked.

Before posting the question I had an acute understanding of the impossibility of a perpetual motion machine. I simply did not understand that a generator wouldn't work due to the amount of resistance required to turn it (which is essentially what I've learned by reading these responses).

I asked the question because I see wind mills appearing to turn quite freely so couldn't understand why the same would not hold true for a vehicle's free wheels. No 'pie in sky' dream of the solution for free energy.

Thank you again for the lay man's explanation.

Also remember when ever you convert from one energy (mechanical) to another (electrical) you always lose some in between.

Hybrid/electric car has regenerating braking for a long time. It help reducing brake because the generator induce drag. It regenerate a little amount of energy to recharge the battery for a bit longer drive time.

Pineapple

"I asked the question because I see wind mills appearing to turn quite freely..."

They only appear that way. It actually takes quite a lot of energy to turn a windmill and even more once you connect a generator to it.

Theoretically, it is actually possible. 2 motors driven by the battery and coupled to 1 pair of wheels to power the car, and 2 generators couple to the other pair of wheels to generate the power. In reality, it is impractical to do so as the generators must of necessity be much smaller than the motors so that they will not offer too much resistance to forward motion. This means that the amount of electricity produced will be much lower than the car requires to propel it. As for the hydrogen generator that was supposedly confiscated by government agents, just remember that the formula for water is H2O, so 1 mole of water can only produce a maximum of 1 mole of H2 gas and half a mole of O2 gas, and that's only when all the water has been electrolyzed to H2 and O2. Oh yes, and when that happens, there will be no more water to absorb the electricity used in the process, which will cause a spark that will probably ignite the highly explosive H2 and O2 gas mixture. I guess then what really happened to the inventor wasn't that his invention was confiscated, but rather his lack of knowledge of science and engineering caused him to discover this the hard way.

Theoretically, it is actually possible. 2 motors driven by the battery and coupled to 1 pair of wheels to power the car, and 2 generators couple to the other pair of wheels to generate the power. In reality, it is impractical to do so as the generators must of necessity be much smaller than the motors so that they will not offer too much resistance to forward motion. This means that the amount of electricity produced will be much lower than the car requires to propel it.

It has absolutely zero to do with the physical size of the generators it has to do with the fact that you can never get any more energy out of a system than you put into it. If you wanted to fit the generators in there is no reason you could not use rare earth magnets in the generators and make them smaller than the motors. Even if you managed to fit the generators in they would never generate the amount of power being consumed by the motors.

I am however in agreement with you about the lunatic that was generating the hydrogen. The authorities probably found out what he was up to, in his shed at the bottom of the garden and confiscated the equipment before he managed to blow himself and half the neighborhood half way to the moon. I suppose that would mean he was only half a lunatic rather than a full lunatic.

Hi Dr.Smith,

"You guys spend allot of energy on total friggin' morons."

That's not very charitable and judging by Oliver's response that is not the case. By the way Oliver thank you for your response and you are welcome. I have no problems spending how ever long it takes with people that are genuinely willing to learn and you appear to be someone that is willing to learn.

I see that this is an old topic but I'll try anyway because I am curious. Some diesel locomotives create electricity to power the trains. So in another forum we are discussing having something similar in a car. . . that is having a small gas engine, turning a 100 amp motor, here is the link from some yocal who says he's done it. . . . http://www.motherearthnews.com/Green-Transportation/1979-07-01/An-Amazing-75-MPG-Hybrid-Electic-Car.aspx

. . . . and he claims that this generator is working in conjunction with some battery power. And then he claims well, the way I see it, is the gas combustion of the electric generator is basically more efficient than that of the gas powered car engine.

Can you explain why this is impossible and also why the trains are using diesel to create electricity to power their engines? Thanks!!!

Diesels run at maximum efficiency at a certain RPM. It is more efficient to use the diesel to make electricity and then use that electricity to turn the wheel with pwm electric motors.

You can do the same with cars, in fact the modern hybrids do this.

Cars run on steeper slopes compared to railways, in general, thus the range of speed from a car motor is greater than a train motor, as is the degree of acceleration.

Modern hybrids use a small diesel engine to run a generator and they also have a battert. The battery runs the drive motors and also is enough to ioperate the car at average speed, no acceleration.

Hybrids often have max speed/endurance limits and then when the battery is run down will run on diesel alone at some max speed,

Read more on google

Spot on aurizon. The only thing I would add is the use of regenerative braking.

Normally the braking in a vehicle (train, car, etcetera) involves retarding the motion with some form of friction device that converts kinetic energy into heat. However, if you are using electric motors to drive the vehicle you can use them to slow the vehicle down or in other words tern them into a generators rather than a motors. This enables you to recover around 50% kinetic energy and turn it back into electrical energy that can be used to get the vehicle moving again.

With the normal stop start motion of city traffic recovering energy through regenerative braking can produce a significant improvement in economy and can easily be the major factor in the overall improvement in economy.

Diesel-electric locomotives use regenerative braking extensively as it gives better control over the deceleration and they normally don't worry about trying to recover the energy. However, with purely electric trains that run on some sort of overhead or third rail power they often use the regenerative braking to feed power back into the distribution network and recover it that way.

Another factor with diesel-electric locomotives is that you can use overhead or third rail electricity to directly power the electric motors and shut down the diesel generator part when the line is electrified. This isn't that common but I have seen a couple of diesel‑electric locomotives that have pantographs that can run directly from overhead cables.

Something I forgot to mention was the performance. Electric motors create torque over their entire range of operating speeds and operate efficiently over a much greater range of speeds than internal combustion motors. As a result electric vehicles can have quiet startling performance characteristics and out perform petrol powered vehicles particularly in a standing start.

Not long ago I saw a race track comparison between a home built electric vehicle, a Ferrari and a NASCAR. The electric vehicle's top speed was nothing like that of its competitors but when it came to acceleration and braking it completely outclassed them. From a standing start it easily took the lead and mane it impossible for the others to produce the acceleration and braking that would be needed to pass it.

The important factor here is that it's not the top speed and power that is important as even with a super car like a Ferrari or pure bread racing vehicle as you very rarely get to it. What is important is the acceleration and deceleration which is where electric motors easily out perform their petrol counterparts.

CR4 Moderator's Note: The comments by Dr. Smith to which several users refer have been removed from this site.