HI,

I have a battery operated 1.5 v electric dc motor 1 whose axle is connected with the axle of another 1.5 v electric dc motor 2.
When I connect a 1.5 volt battry to dc motor 1, and connect a voltmeter to the dc motor 2, i get an d.c. output of 1.5 v.
The moment i remove the battery the output of dc motor 2 goes to zero
I need to design a circuit so that the output of the dc motor 2 charges a capacitor and that in turn powers dc motor 1.
Is it possible to design such a circuit.

 

Sounds like a perpetual motion machine. You can build such a circuit but it wouldn't do anything. THere are losses in charging the capacitor and frictional losses in the motor. Even in a perfect world where perpetual motion machines world, having the capacitor there doesn't make any difference. You might as well just power DC motor 1 directly from DC motor 2.

There are losses when you connect the main battery to the system so the energy that would be stored in your capacitor would always be less than the energy that you drew from the battery. As the energy cycled through back and forth from the capacitor after you removed the battery, you would lose energy each time until you had no energy left and the system stopped. In real life, nothing visible would happen other than the system just stoppig because capacitors don't store much energy in the first place and would dissipate all its energy almost instantly after removing the battery.

It's the same as pouring water back and forth between two cups, and spilling a bit each time. Eventually you end up with no water left, and none of that water was used to do anything useful. In a perfect, frictionless, lossless world, the thing would run forever (but so would just getting a single motor to start spinning and then disconnecting the battery, no friction so it keeps spinning forever). Both systems would stop when you tried to draw energy from them since you then remove the energy from the system. It wouldn't keep running. All that is happening is the intial energy in the system has no where to go. As soon as you remove it by using it to power something else, the system stops.

 

Hi Dknguyen,

Thanks for replying to my query. I have tried powering the 1st DC motor from the output of the 2nd DC motor, but everytime i remove the battery both the motors stop runnning.
I have checked some ckts online which use a 1 V Panasonic backup capacitor to store the charge on the capacitor for a longer time, but as u mentioned that losses would affect the performance in the long run.
Is there any other alternative ckt so that I can run the DC Motor 1 from the output of DC Motor 2.

 

What's the purpose of this?

__________________
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http://www.blueroomelectronics.com

 

As you've already been told, what you're trying to do is impossible, pertetual motion can't work.

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The original post doesn't mention perpetual motion, perhaps it's for a wind power project. The wind never seems to cooperate and running in and out of the house every few minutes is frustrating. Which reminds me, I need to find a speed control for my electric drill...

Anyway, so what if perpetual motion doesn't work, sometimes it's fun and educational to just play with electronics. It's basically harmless, and who doesn't have a box full of motors saved from toys, cassette players, VCRs and such, that have been in the box since being salvaged? Imagination and experimentation are good things. Maybe you won't get the free energy, but you can get more efficient use trying to find it... Isn't energy saved from being wasted, free energy? Suppose your car uses a gallon of gas per day, wouldn't be nice if it would last the entire week?

I betting most everyone here has messed with at least on perpetual motion scheme during their younger years, just out of curiosity. Knowing from the start it wouldn't work, but wondering how long it would run anyway...

 

I've got that one figured out...and have stretched it to a month!
I BIKE!

Ken

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DWI ? Just kidding. That's great, hopefully a good portion of consumers can reduce their use as well, lower demand = lower prices. Unfortunately, a bike wouldn't be practical for me, it's a 40 minute drive to work, so at least couple of hours to ride a bike, on very flat land. I'd be too drain to actually do my job, get fired... and no gas consumption. Could really save some money there, or is it saving, if you don't have it?

Work and groceries are about all the driving I do, about as minimal as I can get. Most everything else is walking distance, and I have to walk the dog anyway...

 

May I suggest a small motorcycle then - some can do 100mpg.

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I haven't ridden much since High School, had kind of a religious experience at about 65 MPH. Now, I live in Florida, and don't feel real safe in an SUV (Rollover-Explorer, it was free). Just too many Canadian drivers on the road (just kidding, mostly it's the local Cellphone talkers that provide most of the close calls these days).

 

Most Canadians driving in Florida are French Canadians. They are also dangerous drivers in Canada because they can't read the English on traffic signs. When a sign says STOP then they drive through CRASH!.

People driving and on cell phones should be shot. They are worse than drunks.

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