Pendulum Generator

[robnisch]

I have been watching some vids on You Tube.
It looks like one can generate power using magnets and coils. But size of the pendulum needs to be rather large.
Does the rotation of the earth have an effect on a relatively small pendulum?
No, I am not talking about perpetual motion.
I think an old windup clock movement could power it for a long time.
Could you charge batteries or a cell phone?

 

[bilby]

I have been watching some vids on You Tube.
It looks like one can generate power using magnets and coils. But size of the pendulum needs to be rather large.
Does the rotation of the earth have an effect on a relatively small pendulum?
No, I am not talking about perpetual motion.
I think an old windup clock movement could power it for a long time.
Could you charge batteries or a cell phone?

Probably not. The swing of a pendulum cannot be used as a power source; You can store power in it, but the 1LoT says you can't get out more than you put in.

The precession of a foucault pendulum is a different matter, as it is 'powered' by the rotation of the Earth - You could in principle extract some useful power, by slightly slowing the planet and lengthening the day. The rotation of the Earth has an effect on any pendulum; If it is free to precess, then it causes precession; If not, the torque generated energy is typically lost - usually as frictional heat in the bearing from which the pendulum hangs.

The power available by this method is incredibly tiny. For a really big, heavy pendulum, enclosed in a vacuum chamber to eliminate losses to air resistance, and with a really high quality bearing to keep frictional losses as low as possible, I seriously doubt that you could generate anywhere close to sufficient power just to keep the pendulum swinging against those minimal frictional losses, much less extract any useful power for other purposes.

I can't be arsed to do the sums, but if someone else wants to have a crack, I have five bucks that says you can't get more than a nanowatt out of any pendulum made from regular baryonic matter at standard temperature and pressure, that would fit in any currently existing building, even assuming frictionless bearings and zero air resistance.

My gut feeling is that a system that rotates at 0.0007 RPM simply cannot generate enough torque to be useful. But perhaps I don't know what I am torquing about...

 

[steve_bank]

Terms first.

Energy is in Joules a scalar
Power in watts is joules per second a vector

It s common to conflate the two terms.

Move a magnet past a coil and current is induced inn the coil. There arr linear genertors that go back back and firth and rotating generators lie a turbine.

So a pendulum can be used to generate electricity. When you lift the end of a pendulum like a kids swing you are transferring chemical energy in your body to gravitational potential energy in the pendulum. The kid on the swing holds a magnet and every time it passes a coil current induced is used to light an LED. An equal and opposite magnateic force is felt by the magfnet held by the kid slowing down the pendulum. Simplified but that is it.

I believe the Coriolis effect will have a negligibly small effect on a pendulum. Or a tree or buidng.

Coriolis force - Wikipedia

en.wikipedia.org

Interesting idea but I think it has been done. Windup emergency radiosand cell phone chargers.

You oulcd use a windup clock to generate electricity.

The thing is conservation of energy. If you want add 1000 Joules of energy to a bhatery youi have to have an energy source off 1000 1Joules plus more for system efficiency losses.

If you want to use a clock to put energy in a battery the physical work you do winding the clock equals the energy put into the clock spring Tere are add on bicyle cell phoe chrgers...

You can buy exercise bike electrical generators. There are add on bicycle cell phone chargers.

Bicycle generators by a wheel to power lights at night have been around at least since the 1950s.

For a small ultra low powerr clock you could use a super capacitor and a small hand generator to charge the capacitor.

 

[Bronzeage]

I have been watching some vids on You Tube.
It looks like one can generate power using magnets and coils. But size of the pendulum needs to be rather large.
Does the rotation of the earth have an effect on a relatively small pendulum?
No, I am not talking about perpetual motion.
I think an old windup clock movement could power it for a long time.
Could you charge batteries or a cell phone?

You would do better to use the old clock movement and let the pendulum do it's job of regulating how fast the mainspring unwound.

There are You Tube creators who specialize in bogus and unsupported science. Their goal is to get views from people who like to be right about stuff. It's quite a large market segment.

 

[Tigers!]

Interesting idea but I think it has been done. Windup emergency radiosand cell phone chargers.

You oulcd use a windup clock to generate electricity.

The thing is conservation of energy. If you want add 1000 Joules of energy to a bhatery youi have to have an energy source off 1000 1Joules plus more for system efficiency losses.

If you want to use a clock to put energy in a battery the physical work you do winding the clock equals the energy put into the clock spring Tere are add on bicyle cell phoe chrgers...

You can buy exercise bike electrical generators. There are add on bicycle cell phone chargers.

An Australian, Alfred Traegar, developed the pedal radio (You Tube) in c. 1927. Helped the Royal Flying Doctor service and the School of the Air immensely.

Bicycle generators by a wheel to power lights at night have been around at least since the 1950s.

For a small ultra low powerr clock you could use a super capacitor and a small hand generator to charge the capacitor.

 

[steve_bank]

It is hard to come up with a new idea in general technology these days.

 

[steve_bank]

How much energy from a pendulum? Looking at it from Laws Of Thermodynamics, conservation of energy.

Gravitational Potential Energy GPE = m*h*g in Joules,

m - mass in kg
h = height in meters
g = 9.8m/s^2
1 watt = 1Joule per second

Raise a 10kg ball 1 meter above the ground. You have added 10kg*1m*9.8m/s^2 = 98Joules of GPE to the ball. Drop it and the energy appears as heat, deformation of ball, and displacement of dirt when it hits the ground

Imagine a pendulum 1 meter long with negligible mass of the arm and a 10kg ball on the end. One end is connected to a shaft that turns a generator.

Raise the pendulum to be parallel to the ground. The starting energy of the system is then 98 Joules.

Release he pendulum. The max rate of change of energy or max power occurs at max speed of the pendulum. The bottom of the arc. The math of the motion is all online.

Mathematically a pendulum and a parallel electrical resistor inductor capacitor circuit are the same. The natural response is that of a 2nd order differential equation, a decaying sine wave. Like a ringing bell.

So ignoring losses 98 Joules of GPE can be transferred to electrical charge on a capacitor by a generator. The cap can supply 1 watt for 98 seconds or 98 watts for 1 second. Signing practical design considerations.

A simple digital wristwatch uses micro watts.

You can assume efficiency losses and do a what if analysis to see how much weft and height re needed to run a digital clock or charge a cell phone.

Another way would be a well or tower and a crank like in the old cowboy shows. Have a deep hole or high tower with a weight at the end of a rope. Wind up the rope on a drum using a winch, Attach the generator to the drum and drop the weight.

 

[robnisch]

How much energy from a pendulum? Looking at it from Laws Of Thermodynamics, conservation of energy.

Gravitational Potential Energy GPE = m*h*g in Joules,

m - mass in kg
h = height in meters
g = 9.8m/s^2
1 watt = 1Joule per second

Raise a 10kg ball 1 meter above the ground. You have added 10kg*1m*9.8m/s^2 = 98Joules of GPE to the ball. Drop it and the energy appears as heat, deformation of ball, and displacement of dirt when it hits the ground

Imagine a pendulum 1 meter long with negligible mass of the arm and a 10kg ball on the end. One end is connected to a shaft that turns a generator.

Raise the pendulum to be parallel to the ground. The starting energy of the system is then 98 Joules.

Release he pendulum. The max rate of change of energy or max power occurs at max speed of the pendulum. The bottom of the arc. The math of the motion is all online.

Mathematically a pendulum and a parallel electrical resistor inductor capacitor circuit are the same. The natural response is that of a 2nd order differential equation, a decaying sine wave. Like a ringing bell.

So ignoring losses 98 Joules of GPE can be transferred to electrical charge on a capacitor by a generator. The cap can supply 1 watt for 98 seconds or 98 watts for 1 second. Signing practical design considerations.

A simple digital wristwatch uses micro watts.

You can assume efficiency losses and do a what if analysis to see how much weft and height re needed to run a digital clock or charge a cell phone.

Another way would be a well or tower and a crank like in the old cowboy shows. Have a deep hole or high tower with a weight at the end of a rope. Wind up the rope on a drum using a winch, Attach the generator to the drum and drop the weight.

Thanks for the math, Steve. I just thought it would be a fun project.

 

[steve_bank]

All these kinds of Newtonian scale problems generally can be looked at through Laws Of Thermodynamics without knowing how something works.

Energy, power, efficiency, conservation, no perpetual motion, and work.

 

[steve_bank]

Yes, a Foucault pendulum can technically be used to generate a very small amount of electricity, but it is not a practical or efficient power source. By attaching magnets to the pendulum bob and surrounding it with coils, the pendulum's motion can generate electrical energy, essentially acting as a transducer for its kinetic energy.

Mechanism: The swinging, magnetized pendulum induces a current in surrounding coils as it moves.

Low Output: Experiments have shown that such devices produce extremely low voltage, such as 17 microvolts, which is significantly less than what is needed for practical applications [2, Nature, Futurism https://futurism.com/scientists-generate-electricity-earth-rotation].

Energy Consumption: Because of friction and air resistance, Foucault pendulums require constant energy input (often via electromagnets) to keep swinging [5, 7, University at Buffalo]. The energy needed to maintain the swing is far greater than the electrical energy generated.

Purpose: While a patented concept exists for using a magnetized pendulum to create power, these devices are predominantly used as educational exhibits to demonstrate Earth's rotation, rather than as functional generators.

Interesting that there is a patentt for a Foucault power gernerator.

US8299636B2 - Magnetized foucault pendulum electrical energy source - Google Patents

A magnetized Foucault Pendulum electrical energy source having a gear transmission connected between the rotatable Foucault Pendulum and an electrical generator. A portion of the current from the generator is transmitted to an electromagnet which is periodically energized to repel a mass on the...

patents.google.com

SUMMARY OF THE INVENTION
The Foucault pendulum of the present invention is magnetized and has a gear transmission connected between the rotatable pendulum and an electrical generator. A portion of the current from the generator is transmitted to an electromagnet which is periodically energized to repel a mass on the end of the pendulum, whereby the pendulum is maintained in continuous motion. The remaining portion of the electrical current is transmitted to individual households or to a power grid.

 

[Elixir]

Interesting that there is a patentt for a Foucault power gernerator.

I designed a perpetual motion machine that generates quite a bit of energy. It drives a generator that can provide variable output at whatever level is desired, by means of a simple throttle mechanism. All you have to do is keep pouring gasoline, ethanol or other combustible liquid into the tank, and it gravity feeds itself to a combustion chamber ….

 

[Bomb#20]

Interesting that there is a patentt for a Foucault power gernerator.

US8299636B2 - Magnetized foucault pendulum electrical energy source - Google Patents

A magnetized Foucault Pendulum electrical energy source having a gear transmission connected between the rotatable Foucault Pendulum and an electrical generator. A portion of the current from the generator is transmitted to an electromagnet which is periodically energized to repel a mass on the...

patents.google.com

SUMMARY OF THE INVENTION
The Foucault pendulum of the present invention is magnetized and has a gear transmission connected between the rotatable pendulum and an electrical generator. A portion of the current from the generator is transmitted to an electromagnet which is periodically energized to repel a mass on the end of the pendulum, whereby the pendulum is maintained in continuous motion. The remaining portion of the electrical current is transmitted to individual households or to a power grid.

Who's the Einstein in the patent office who approved that?

 

[Bomb#20]

Probably not. The swing of a pendulum cannot be used as a power source; You can store power in it, but the 1LoT says you can't get out more than you put in.

The precession of a foucault pendulum is a different matter, as it is 'powered' by the rotation of the Earth - You could in principle extract some useful power, by slightly slowing the planet and lengthening the day. The rotation of the Earth has an effect on any pendulum; If it is free to precess, then it causes precession; If not, the torque generated energy is typically lost - usually as frictional heat in the bearing from which the pendulum hangs.

The power available by this method is incredibly tiny. For a really big, heavy pendulum, enclosed in a vacuum chamber to eliminate losses to air resistance, and with a really high quality bearing to keep frictional losses as low as possible, I seriously doubt that you could generate anywhere close to sufficient power just to keep the pendulum swinging against those minimal frictional losses, much less extract any useful power for other purposes.

I can't be arsed to do the sums, but if someone else wants to have a crack, I have five bucks that says you can't get more than a nanowatt out of any pendulum made from regular baryonic matter at standard temperature and pressure, that would fit in any currently existing building, even assuming frictionless bearings and zero air resistance.

My gut feeling is that a system that rotates at 0.0007 RPM simply cannot generate enough torque to be useful. But perhaps I don't know what I am torquing about...

The power available by this method is a big fat zero. Angular momentum is conserved. An object can't change its rotation rate by pushing on itself around its axis any more than Wile Coyote can keep his sail-skateboard going by blowing on his sail. To get power from the rotation of the earth you'd have to dump some of the angular momentum into an external object, such as the moon. So unless the precession of the pendulum somehow torques the moon you're getting zilch.

(* An object can reduce its rotation rate by pushing on itself radially, moving mass farther from its axis, increasing its moment of inertia. Climb a flight of stairs and you've slowed the Earth. But (a) a pendulum doesn't do that, and (b) it takes energy to climb stairs. )

 

[steve_bank]

Interesting that there is a patentt for a Foucault power gernerator.

US8299636B2 - Magnetized foucault pendulum electrical energy source - Google Patents

A magnetized Foucault Pendulum electrical energy source having a gear transmission connected between the rotatable Foucault Pendulum and an electrical generator. A portion of the current from the generator is transmitted to an electromagnet which is periodically energized to repel a mass on the...

patents.google.com

SUMMARY OF THE INVENTION
The Foucault pendulum of the present invention is magnetized and has a gear transmission connected between the rotatable pendulum and an electrical generator. A portion of the current from the generator is transmitted to an electromagnet which is periodically energized to repel a mass on the end of the pendulum, whereby the pendulum is maintained in continuous motion. The remaining portion of the electrical current is transmitted to individual households or to a power grid.

Who's the Einstein in the patent office who approved that?

Patents don't have to be practical. Often a patent serves as office wallpaper.

 

[steve_bank]

To be pedantic whether or not a volume in space is a source or a sink is mathematically determined by divergence.


It applies to a battery or water flow in a pipe.

A battery is a source, a resistor is sink,

You can store energy in a battery, then use it to do work like moving electrons.


A pendulum can store energy, GPE. When released the pendulum can do work.

A battery runs down, a pendulum runs down. Both are subject to LOT.

An energy source like coal or natal gas are rated in energy density, Joules/kg Joules/liter.

A power source like a turbine is rated in watts, Joules/second.

When being charged a battery is a sink. When used it is a source.

Energy source or power source depends on circumstances.

 

[bilby]

Probably not. The swing of a pendulum cannot be used as a power source; You can store power in it, but the 1LoT says you can't get out more than you put in.

The precession of a foucault pendulum is a different matter, as it is 'powered' by the rotation of the Earth - You could in principle extract some useful power, by slightly slowing the planet and lengthening the day. The rotation of the Earth has an effect on any pendulum; If it is free to precess, then it causes precession; If not, the torque generated energy is typically lost - usually as frictional heat in the bearing from which the pendulum hangs.

The power available by this method is incredibly tiny. For a really big, heavy pendulum, enclosed in a vacuum chamber to eliminate losses to air resistance, and with a really high quality bearing to keep frictional losses as low as possible, I seriously doubt that you could generate anywhere close to sufficient power just to keep the pendulum swinging against those minimal frictional losses, much less extract any useful power for other purposes.

I can't be arsed to do the sums, but if someone else wants to have a crack, I have five bucks that says you can't get more than a nanowatt out of any pendulum made from regular baryonic matter at standard temperature and pressure, that would fit in any currently existing building, even assuming frictionless bearings and zero air resistance.

My gut feeling is that a system that rotates at 0.0007 RPM simply cannot generate enough torque to be useful. But perhaps I don't know what I am torquing about...

The power available by this method is a big fat zero. Angular momentum is conserved. An object can't change its rotation rate by pushing on itself around its axis any more than Wile Coyote can keep his sail-skateboard going by blowing on his sail. To get power from the rotation of the earth you'd have to dump some of the angular momentum into an external object, such as the moon. So unless the precession of the pendulum somehow torques the moon you're getting zilch.

(* An object can reduce its rotation rate by pushing on itself radially, moving mass farther from its axis, increasing its moment of inertia. Climb a flight of stairs and you've slowed the Earth. But (a) a pendulum doesn't do that, and (b) it takes energy to climb stairs. )

Is angular momentum necessarily conserved here though? If I generate electricity from a flywheel, the angular momentum decreases; Why can't the same happen here, with the Earth acting as our flywheel?

 

[Bomb#20]

The power available by this method is a big fat zero. Angular momentum is conserved. An object can't change its rotation rate by pushing on itself around its axis any more than Wile Coyote can keep his sail-skateboard going by blowing on his sail. To get power from the rotation of the earth you'd have to dump some of the angular momentum into an external object, such as the moon. So unless the precession of the pendulum somehow torques the moon you're getting zilch.

(* An object can reduce its rotation rate by pushing on itself radially, moving mass farther from its axis, increasing its moment of inertia. Climb a flight of stairs and you've slowed the Earth. But (a) a pendulum doesn't do that, and (b) it takes energy to climb stairs. )

Is angular momentum necessarily conserved here though? If I generate electricity from a flywheel, the angular momentum decreases; Why can't the same happen here, with the Earth acting as our flywheel?

It's certainly possible to generate power from the earth acting as a slowing flywheel -- it's happening naturally to the tune of about 20% of mankind's total power use -- but all that power is being used to lift the moon into a higher orbit. Angular momentum is always conserved. When you generate electricity from a flywheel, its angular momentum decreases because the flywheel is increasing the angular momentum of the electrons in your generator, which isn't on the flywheel; likewise, the slowing earth increases the angular momentum of the moon, which isn't on the earth. If the moon were on the earth, pulling on it wouldn't slow the earth down, just as if the generator were on your flywheel pulling on it wouldn't slow the flywheel down.

 

[steve_bank]

On the surface of the Earth both flywheel and generator are fixed to the Earth. The Princeton Tokamak fusion rector used a flywheel to initiate fusion, the grid could not supply the instantaneous power. The flywheel was spun up slowly.

You can buy commercial flywheel energy storage systems.

Flywheel generators slow down because magnetic induction creates a counter torque opposing the flywheel rotation.

Generate 1 watt of electrical power and ignoring loses 1 Joule of energy is deducted from the flywheel energy. The change in speed can be calculated from that.

Same principle with a magnetic resistance exercise bike, or magnetic brakes in a car.

Tapping the Earth’s rotational kinetic energy would require a fixed place to push against.

The atmosphere is a gigantic capacitor. Tap into that. But again on a large scale potetial consequences.

Total Stored Energy: Estimates indicate this atmospheric capacitor stores approximately 7,000,000,000,000 Joules (\(7\times 10^{12}\) J or 7 Terajoules) of energy.

Nikola Tesla actively tried to extract and harness electricity from the atmosphere in the early 1900s. He believed the Earth and its upper atmosphere behaved as200 billion-volt capacitor, theorizing that this "cosmic energy" could be harvested, transmitted wirelessly, and used as a free, renewable power source.

 

[Elixir]

Tapping the Earth’s rotational kinetic energy would require a fixed place to push against.

Don’t tidal generators do that?

 

[steve_bank]

I think tides are caused by Moon and Sun Gravity.

Tide - Wikipedia

en.wikipedia.org

Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another.

Earth tide - Wikipedia

en.wikipedia.org

Earth tide (also known as solid-Earth tide, crustal tide, body tide, bodily tide or land tide) is the displacement of the solid earth's surface caused by the gravity of the Moon and Sun.<a href="https://en.wikipedia.org/wiki/Earth_tide#cite_note-1"><span>[</span>1<span>]</span></a>Its main component has meter-level amplitude at periods of about 12 hours and longer. The largest body tide constituents are semi-diurnal, but there are also significant diurnal, semi-annual, and fortnightly contributions.<a href="https://en.wikipedia.org/wiki/Earth_tide#cite_note-2"><span>[</span>2<span>]</span></a>Though the gravitational force causing earth tides and ocean tides is the same, the responses are quite different.

Ocean tidal loading is the deformation of the underlying crust in response to periodic variations of water mass associated with the ocean tide, and is typically one order of magnitude smaller than the body tide deformation.[7] Sensitive instruments far inland often have to make similar corrections. Atmospheric loading and storm events may also be measurable, though the masses in movement are less weighty.