Maker Pro
Maker Pro

noob here.... can i use a generator to power my electric motor (woo woo)

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
i am aware that NO electrical system will be 100% perfect 100% of its life
That's not the point. No device that converts energy from one form to another can produce more energy than it uses; no such device can even convert with 100% efficiency.
in my mind its a complex conversion of Electrical energy in -> kenetic energy out -> Kenetic Energy in-> electrical energy out ->repeat...
Congratulations, you know what kinetic energy is! Now you need to learn about efficiency and loss when converting energy from one form to another.
this question has been thrown up because you CAN run a car WITHOUT a battery.... just using its alternator...... so.... HOW can it, if it needs to power itself?
It gets its energy from the petrol (gas) in the tank. This is derived from oil, a fossil fuel, which contains a lot of stored energy. When the tank is empty, the engine doesn't run any more, does it?
plus this system works
No, I'm afraid it DOESN'T work. It is either a joke, a con, or a troll.

This thread violates the Electronics Point posting guidelines and is in danger of being closed. What you are talking about is impossible according to the current laws of physics. If you want to defeat those, you first need to understand them!
 

Gryd3

Jun 25, 2014
4,098
Joined
Jun 25, 2014
Messages
4,098
This will be my last reply:

Let's assume an efficiency of 90% (Which is high)
Gasoline has an energy density of 32.4 MJ/L or 9KWh
Your generator is a 48KW Generator, which would require 6L/H to feed at it's highest capacity...
Now... if we hook up a 30KW motor, the generator would only need to provide 30KW... so it would only consume 3.7L/H
The additional 18KW that the generator is capable of, is not being created because there is no-where for the energy to go...
Now, if we took the output from the 30KW motor and fed it back to the generator, the generator would recover 24.3KW (remember 90% effeciency... 30KW from genny = 27KW to motor = 24.3KW back to genny)
This means that for this single loop, there is 5.7KW lost. This lost energy must come from the gasoline engine which will use up 0.7L/H to make up for the lost energy. When the gas runs out, the 5.7KW lost each cycle will quickly drain the system of energy and the motor and generator will halt.
OK... so now you added batteries... the extra 18KW that was unused before will go into the batteries... but remember that by not using it to begin with... we used less gas / hour. Even if you took the extra and stored it in a battery, the batteries will hold less energy than the gasoline did.

I think it's about time that you write down a mathematical equation. If you don't know it. Guess.
You will soon realize that the losses are what kills your idea.

this isnt so correct for diesels.... the very first diesel engines had no ignition or alternator, just a hand crank they would run as long as the engine was turning.... the the parts were mechanically driven (fuel was drawn by vacuum)
the start up and stop was on a valve linked to the fuel lines.... valve closes, starves engine of fuel, engine dies, turn button, valve opens, crank engine over, engine runs
diesels only use electrics now for monitoring and control (eco) purposes
Do you know what a Glow Plug is? Diesel engines require a certain amount of heat AND compression to ignite the fuel. They don't just run by themselves. Some of the lost energy in burning the fuel is heat, which luckily enough, is recouped by igniting the cylinder again. A gas engine required electrical energy to be converted to do this... but in any case, this is still energy that is siphoned off from the fuel.
You also put a lot of energy into compressing the fuel... as the compression ratio needs to be much higher than gasoline to ignite.

plus; alternators run at 14.7V on a flat battery (12V car battery) whereas a battery charger (UK 230V) will charge at 13.8V from flat.... or 2.5-8V deeply drained

i car nowadays will use around 110A for start up then 50A while running due to the electronic ecu, pumps, fans, ignition, radio, demist, internal heating, wipers, heated seats, tyre pressure monitors, turbo boost and spool readings, PAS, ABS, exhaust readings, alternator readings, battery readings, headlights, air bags, horn, impact zone sensors...... etc
What is your point here?
50A is 600Watts which is roughly 62mL of gasoline an hour to maintain. (The engine idling for example)
 

hevans1944

Hop - AC8NS
Jun 21, 2012
4,878
Joined
Jun 21, 2012
Messages
4,878
This will be my first and last reply to this particular thread, ever. Go ahead @chisechi "money is no object" and purchase the motor and the generator sets. Let us know how that works for you. The video you posted is a fraud. I don't even have to be there to "witness" this so-called "ground zero" lash-up to know it is a fraud. Your so-called "calculations" involving generator power versus motor power demonstrate a complete lack of understanding of even the most simple physical principles. This thread was and is a total waste of time, although it is interesting to see that P.T. Barnum is still correct in his observations about people.
 

BobK

Jan 5, 2010
7,682
Joined
Jan 5, 2010
Messages
7,682
Do you really think you are the first person to think of spinning a generator with a motor and powering the motor off the generator? Really? Hint: I thought of when I was about 8. It did not work for me then, it did not work for the millions of others who have thought of it. And, after learning a little science (bachelor's degree in physics), I know why it will never work.

Do some reading of real science books, not youtube videos.

Or, if you insist on videos, check out this site. This is real science and math taught very well:

https://www.khanacademy.org/

Bob
 
Top