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Author Topic: A Promethean Thought Experiment  (Read 3593 times)

Offline IggyZ

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  • Posts: 20
Re: A Promethean Thought Experiment
« Reply #15 on: January 20, 2022, 08:29:03 PM »
Even a very small amount of energy transfer per second, can cause the acceleration of a very large mass to a very high speed, if that transfer continues to occur for a long enough period of time.
In the case of a locomotive and cars, wind resistance would eventually become the limiting factor.
This is because wind resistance increases when the speed of the train increases. The resistance to acceleration against the    inertia of a mass     is a different kind of consideration.  In theory, one can tow a battle ship until is moving very fast (in deep space) by the tug of a thread, if one is patient enough / has enough time to wait.

One could buildup and store energy in the fly wheel.  This can be useful.  On might then
release that energy gradually, or, as some kind of burst of energy.  When the energy is released
as a burst / a large amount at once, this it seems, often confuses experimenters into thinking
more energy has come out of the fly wheel than was put into it.  This confusion it seems is
especially common when these burst occur repetitively as is some times the case in resonating
electromagnetic events.

More to the point here.  If for simplicity, we for the time being ignore friction and some other
kinds of losses, we can look directly at the energy and power transferred or expended in
an electric generator as its conversion to motion via an electric motor.

If an electric generator is able to spin freely, in order to accelerate it, one is only working
against the inertia of the generators rotor.  If an electric generator is able to spin freely,
this is because there is no electrical load upon it (i.e.no electric motor being driven). 

One can eventually give it a very high speed of rotation, given that there is no electrical
load upon it (ignoring friction and so on for now).

The power to weight ratio comes into consideration really, only with the considerations of
1. how       rapidly     accelerations can occur
             i.e.  Does one wish to spend a month of time accelerating a train?
                                                            and
2. when going up hill.

                OK ?
Thanks.

OK? Yes and no...

If I understand you correctly, you are saying a power-to-weight ratio of 12 watt per kg (1.600 KW) is enough to give a 140 tons rotor of a generator a speed of 45 kmh, providing there is no electric load on the generator? Correct?

Don't forces like eddy currents and hysteresis occur simply because the magnetic field of the spinning rotor interacts with the stator of the generator? Isn't this always the case whether or not there is an electric load on the generator?

Floor

  • Guest
Re: A Promethean Thought Experiment
« Reply #16 on: January 20, 2022, 09:20:56 PM »

If I understand you correctly, you are saying a power-to-weight ratio of 12 watt per kg (1.600 KW) is enough to give a 140 tons rotor of a generator a speed of 45 kmh, providing there is no electric load on the generator? Correct?

Yes and no.  Power to weight ratio is not part of the equation except that / unless
the power source is on board.


Don't forces like eddy currents and hysteresis occur simply because the magnetic field of the spinning rotor interacts with the stator of the generator? Isn't this always the case whether or not there is an electric load on the generator?

Only when the generator is of a type which uses permanent magnets.

But then also...
 I was speaking in terms of excluding all "losses"  friction, eddy currents and hysteresis,
" magnetic cogging", kinetic energy's converion into unproductive vibrations, others.

Offline IggyZ

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Re: A Promethean Thought Experiment
« Reply #17 on: January 21, 2022, 10:18:24 AM »
Yes and no.  Power to weight ratio is not part of the equation except that / unless
the power source is on board.

Only when the generator is of a type which uses permanent magnets.

But then also...
 I was speaking in terms of excluding all "losses"  friction, eddy currents and hysteresis,
" magnetic cogging", kinetic energy's converion into unproductive vibrations, others.
Thx Floor.

Why is the power-to-weight ratio not part of the equation except that / unless it is on-board the train?

The generator's rotor I use in my thought experiment uses permanent magnets.

The generator's stator in my thought experiment is iron-less = no cogging.

Friction and vibrations are mechanical losses. Aren't eddy currents and hysteresis losses core, copper or stray losses?

It looks like all the losses you list are all covered by the power flow diagram and the fact I use a permanent magnet generator with an iron-less core in my thought experiment. Thus most of the mechanical input power should be converted into electricity.

Floor

  • Guest
Re: A Promethean Thought Experiment
« Reply #18 on: January 21, 2022, 12:20:14 PM »
@ george1

It's like this

There are commonly two power to weight ratio considerations that are looked at
in this arena (energy and efficiency wise).

1. Energy or power density, as in how much do the electric batteries in an electric
vehicle weigh compared to the number of amp or watt hours they can deliver on
a single charge.  The power source is on board.

2. One seeks the rapid acceleration of, for example a fast automobile. In the U.S.
this is typically judged by the car's ability to accelerate from 0 to 60 miles per hour in
some number of seconds. This is another kind of "efficiency".

The best of conventionally available electric generators are > 98% efficient at
converting mechanical power into electrical power.

  All in all...

This is why I have said that your usage of terms does not make sense / is like
comparing apples to oranges.  i.e. "power-to-weight ratio" in the context in which
you use the phrase.


          P.S.
  It remains that you have not responded to a single one of my questions and
that your topic is just more click bait.

Floor

  • Guest
Re: A Promethean Thought Experiment
« Reply #19 on: January 21, 2022, 03:28:28 PM »
or

Will you please ...

state simply, the basic premise of your "Promethean thought experiment" ?

Question...

Does a flat ended, rotating cylindrical disk with a total mass of 1 kg, while its outer
edge is rotating at a speed of 1 meter per second..
                        posses
as much kinetic energy as does that same object when not rotating, but which is
instead, moving in a straight line of travel, at a speed of 1 meter per second ?

Answer is no.  When moving in a straight line all of the mass is moving at 1 meter per
second.  When rotating, the mass of the object is distributed as moving at speeds of
from zero meters per second to 1 meter per second.
                          From its center (0m/s) to its edge (1m/s).

Is it not ?

Offline IggyZ

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  • Posts: 20
Re: A Promethean Thought Experiment
« Reply #20 on: January 21, 2022, 08:33:34 PM »
@ george1

It's like this

There are commonly two power to weight ratio considerations that are looked at
in this arena (energy and efficiency wise).

1. Energy or power density, as in how much do the electric batteries in an electric
vehicle weigh compared to the number of amp or watt hours they can deliver on
a single charge.  The power source is on board.

2. One seeks the rapid acceleration of, for example a fast automobile. In the U.S.
this is typically judged by the car's ability to accelerate from 0 to 60 miles per hour in
some number of seconds. This is another kind of "efficiency".

The best of conventionally available electric generators are > 98% efficient at
converting mechanical power into electrical power.

  All in all...

This is why I have said that your usage of terms does not make sense / is like
comparing apples to oranges.  i.e. "power-to-weight ratio" in the context in which
you use the phrase.


          P.S.
  It remains that you have not responded to a single one of my questions and
that your topic is just more click bait.
I think I now understand why you are confused by my use of the power-to-weight ratio term. Thanks. I am sorry it caused confusion. It is probably  smarter to discuss this in terms of electricity consumption vs. electricity generation

You say:"
The best of conventionally available electric generators are > 98% efficient at converting mechanical power into electrical power". I guess it is fair to say the power flow diagram is correct.

Offline IggyZ

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  • Posts: 20
Re: A Promethean Thought Experiment
« Reply #21 on: January 21, 2022, 09:10:34 PM »
or

Will you please ...

state simply, the basic premise of your "Promethean thought experiment" ?

Question...

Does a flat ended, rotating cylindrical disk with a total mass of 1 kg, while its outer
edge is rotating at a speed of 1 meter per second..
                        posses
as much kinetic energy as does that same object when not rotating, but which is
instead, moving in a straight line of travel, at a speed of 1 meter per second ?

Answer is no.  When moving in a straight line all of the mass is moving at 1 meter per
second.  When rotating, the mass of the object is distributed as moving at speeds of
from zero meters per second to 1 meter per second.
                          From its center (0m/s) to its edge (1m/s).

Is it not ?
I do not know if you are correct since I can't do the math to prove whether you are right or not. Also the disk is attached to an axis. If it would break away from its axis its kinetic energy might be the same as that of the mass moving in a straight line. Their mass is the same so I guess it depends on how much energy was needed to spin the disk and how much energy was needed to move the mass in a straight line.

 

Floor

  • Guest
Re: A Promethean Thought Experiment
« Reply #22 on: January 22, 2022, 12:24:55 AM »
Cool. I think of your idea / thought experiment as really, not too shabby at all.

Welcome to Overunity.com.

When a subject is of interest to me, I find it usually is not to much effort to pick up
 / learn, a little more math when the need comes along.

I find this is easier when I have something I want to apply the math to.

Keep learning and Keep exploring.

  best wishes

Offline IggyZ

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  • Posts: 20
Re: A Promethean Thought Experiment
« Reply #23 on: January 22, 2022, 01:24:36 PM »
Thank you Floor for your feedback and being willing to stick out your neck! Unfortunately this is rare. Best wishes to you.

I guess it is fair to say it is more than plausible the Prometheus Generator is capable of generating excess energy.

It is possible to drive a 140 tons rotor at a speed of ~ 45 kmh (measured at its edge) using 1600 KW of electricity and most of the mechanical input power is converted to electricity (please see attached picture).

Floor

  • Guest
Re: A Promethean Thought Experiment
« Reply #24 on: January 22, 2022, 05:23:11 PM »
@Iggyz

I guess I'll stick my neck out here again.

Here is a 90 page text (part 1). It was written by a non expert for non experts.
It explains and gives definitions for some basic physics concepts.
It contains very little math, some simple math and also explains the math it does contain.

Some basics of the following.

energy
inertial frame of reference
speed
velocity
gravity
force
acceleration
the forces of acceleration
constant acceleration
acceleration by gravity
inertia
momentum
mass
weight
mass compared to weight
the newton of force
mechanical work
the joule of energy
aspect ratio
time
power

It is called "Magnets Motion and Measurement" PDF and is attached below.

I hope you will find it useful.

        best wishes
             floor

Offline IggyZ

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  • Posts: 20
Re: A Promethean Thought Experiment
« Reply #25 on: January 23, 2022, 12:34:45 PM »
@Floor.
Looks very interesting.
I have no doubt the pdf file ("Magnets Motion and Measurement") attached to your post will be very useful indeed!
Thanks!

Offline IggyZ

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  • Posts: 20
Re: A Promethean Thought Experiment
« Reply #26 on: September 03, 2022, 12:17:20 PM »
Seen on the Internet:"The maximum output electrical power of a generator is equal to the maximum input mechanical times the generator efficiency. Typically for a commercial generator, that is in the order of 95%. So 1 kW of mechanical input power yields 0,95 kW of electrical output power."

Is this the correct wat to calculate the efficiency of a generator?

If it is not  correct I would very much appreciate the correct formula with an example and explanation a lay person can understand.

Offline bistander

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  • Posts: 263
Re: A Promethean Thought Experiment
« Reply #27 on: September 03, 2022, 02:16:06 PM »
Seen on the Internet:"The maximum output electrical power of a generator is equal to the maximum input mechanical times the generator efficiency. Typically for a commercial generator, that is in the order of 95%. So 1 kW of mechanical input power yields 0,95 kW of electrical output power."

Is this the correct wat to calculate the efficiency of a generator?

If it is not  correct I would very much appreciate the correct formula with an example and explanation a lay person can understand.

Hi IggyZ,
Efficiency of a power conversion device is defined as useful power output divided by total power input times 100%.
So if your generator delivers 0.95kW output of real power electrical using 1.0kW of mechanical power input, then it is 95% efficient at that operating point. Fact. By definition. That operating point may, or may not be maximum power. That depends on the actual machine design. Generators can, and do, operate at various loads, or operating points. Typically the generator nameplate will state its rated load, which is seldom its maximum power output. The generator can operate at no-load, partial load, full (or rated) load, overload, or maximum power output load. Efficiency is typically different for every operating point. Decent generator design will have peak efficiency normally somewhat less than full rated load, but efficiency at rated load will be close to max efficiency. Efficiency at maximum power output is typically well below maximum efficiency.
Hope that helps.
bi
« Last Edit: September 03, 2022, 05:23:36 PM by bistander »

Offline Tarsier_79

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  • Posts: 75
Re: A Promethean Thought Experiment
« Reply #28 on: September 03, 2022, 09:47:28 PM »
https://www.youtube.com/watch?v=sENgdSF8ppA&t=1s

This is the reason all the multi-coil OU generators here don't actually create OU. It is also the reason your large radius rotor will not. When your magnet creates voltage and current in your generator, the equvalent force is transferred to the magnet. What you do to the back-emf also affects the magnet.

Electrical current x voltage is power. Power in - frictions -inefficiency = power out.

Even so, I would love to see your generator..

Offline IggyZ

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Re: A Promethean Thought Experiment
« Reply #29 on: September 05, 2022, 03:03:03 PM »
Thank you bistander, it really was helpful.