Peter Daysh Davey Water Heater Query

[PhysicsProf]

Just a quick note, I have been playing with some ideas and have come up with a new concept you guys might be interested in. It may be possible to vary your AC frequency using these ideas. Also if you choose to run two identical water power generators and wire them into the same boiler you could set two different variable frequencies on two separate rings. Two different frequencies is what some plasma researchers are finding creates anomolous effects, as noted in those links I posted.
...
All you sink scientists have fun now!

RM

So how do you "vary your AC frequency "? I'm interested, evolving...
I've done some tests with two coils running at different frequencies (from signal generators) then watching the beat frequencies using a pick-up coil... quite interesting alright!
Wondering if a guy could do this with a Tesla coil... So many avenues to pursue!

[evolvingape]

Hi Professor,

Volume II - AC : All About Circuits

Three-phase power systems : POLYPHASE AC CIRCUITS

“Together, the six “pole” windings of a three-phase alternator are connected to comprise three winding pairs, each pair producing AC voltage with a phase angle 120o shifted from either of the other two winding pairs. “

https://en.wikipedia.org/wiki/Hertz

“The hertz (symbol Hz) is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon.[1] One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications.”

AC waveforms : BASIC AC THEORY

“The reason why an electromechanical alternator outputs sine-wave AC is due to the physics of its operation. The voltage produced by the stationary coils by the motion of the rotating magnet is proportional to the rate at which the magnetic flux is changing perpendicular to the coils (Faraday's Law of Electromagnetic Induction). That rate is greatest when the magnet poles are closest to the coils, and least when the magnet poles are furthest away from the coils. Mathematically, the rate of magnetic flux change due to a rotating magnet follows that of a sine function, so the voltage produced by the coils follows that same function.
If we were to follow the changing voltage produced by a coil in an alternator from any point on the sine wave graph to that point when the wave shape begins to repeat itself, we would have marked exactly one cycle of that wave. This is most easily shown by spanning the distance between identical peaks, but may be measured between any corresponding points on the graph. The degree marks on the horizontal axis of the graph represent the domain of the trigonometric sine function, and also the angular position of our simple two-pole alternator shaft as it rotates.
Since the horizontal axis of this graph can mark the passage of time as well as shaft position in degrees, the dimension marked for one cycle is often measured in a unit of time, most often seconds or fractions of a second. When expressed as a measurement, this is often called the period of a wave. The period of a wave in degrees is always 360, but the amount of time one period occupies depends on the rate voltage oscillates back and forth.
A more popular measure for describing the alternating rate of an AC voltage or current wave than period is the rate of that back-and-forth oscillation. This is called frequency. The modern unit for frequency is the Hertz (abbreviated Hz), which represents the number of wave cycles completed during one second of time. In the United States of America, the standard power-line frequency is 60 Hz, meaning that the AC voltage oscillates at a rate of 60 complete back-and-forth cycles every second. In Europe, where the power system frequency is 50 Hz, the AC voltage only completes 50 cycles every second. A radio station transmitter broadcasting at a frequency of 100 MHz generates an AC voltage oscillating at a rate of 100 million cycles every second.
Prior to the canonization of the Hertz unit, frequency was simply expressed as “cycles per second.” Older meters and electronic equipment often bore frequency units of “CPS” (Cycles Per Second) instead of Hz. Many people believe the change from self-explanatory units like CPS to Hertz constitutes a step backward in clarity. A similar change occurred when the unit of “Celsius” replaced that of “Centigrade” for metric temperature measurement. The name Centigrade was based on a 100-count (“Centi-”) scale (“-grade”) representing the melting and boiling points of H2O, respectively. The name Celsius, on the other hand, gives no hint as to the unit's origin or meaning.
Period and frequency are mathematical reciprocals of one another. That is to say, if a wave has a period of 10 seconds, its frequency will be 0.1 Hz, or 1/10 of a cycle per second:

Frequency in Hertz = 1 / Period in Seconds

An instrument called an oscilloscope, Figure below, is used to display a changing voltage over time on a graphical screen. You may be familiar with the appearance of an ECG or EKG (electrocardiograph) machine, used by physicians to graph the oscillations of a patient's heart over time. The ECG is a special-purpose oscilloscope expressly designed for medical use. General-purpose oscilloscopes have the ability to display voltage from virtually any voltage source, plotted as a graph with time as the independent variable. The relationship between period and frequency is very useful to know when displaying an AC voltage or current waveform on an oscilloscope screen. By measuring the period of the wave on the horizontal axis of the oscilloscope screen and reciprocating that time value (in seconds), you can determine the frequency in Hertz.”

https://en.wikipedia.org/wiki/Alternator

“The output frequency of an alternator depends on the number of poles and the rotational speed. The speed corresponding to a particular frequency is called the synchronous speed for that frequency.

More generally, one cycle of alternating current is produced each time a pair of field poles passes over a point on the stationary winding. The relation between speed and frequency is N = 120f / P , where f is the frequency in Hz (cycles per second). P is the number of poles (2,4,6...) and N is the rotational speed in revolutions per minute (RPM). “

N = 120f / P

https://en.wikipedia.org/wiki/Synchronous_motor

The "synchronous speed" n of a synchronous motor is the rate of rotation in RPM of the stator magnetic field. After startup it is also the rotation rate of the motor:
n = 120f / P
where f is the frequency of the AC supply current in Hz and P is the number of magnetic poles per phase. For example, small 3-phase synchronous motors usually have 6 poles organized as 3 opposing pairs at angles of 120°, each pair powered by one phase, so p = 2. Thus for 60 Hz supply current the synchronous speed is 3600 RPM.

Here in the UK when you buy any kind of motor it will be either 1800RPM 4 pole, or 3600RPM 2 Pole. This is because the motors are designed to operate at the frequency of the supply AC. The difference between the motors is that the slower speed has higher torque, and the faster speed has lower torque.

The reason you cannot change the frequency of the AC coming out of the wall socket, without additional equipment, is because you have no control over it's generation, the supplier uses automatic sensing governers to alter the variables of the power generation equipment at the power plant, so they will always supply 50 or 60 HZ, by increasing or decreasing power generation depending on load demands. Here are some power engineers arguing about it:

Steam turbine generator speed control - clarification

Anyway, you do not really need to know all that to use the information practically. If you set up a Pelton Turbine and connect a 3 phase (6 Pole) alternator to the output shaft you have created a miniature power generation plant. Because the turbine is powered by water, and your tap has a flow control valve, you can change the power input to the turbine, increase or decrease the amount of water spinning it. This gives you variable control over the turbines RPM (N), so with an alternator directly coupled to the turbine in a 1:1 ratio when you alter the RPM of the turbine you alter the RPM of the alternator, and thus the frequency of the AC sinusoidal waveform generated. For a fixed load such as an electrode boiler you will of course alter the power being supplied to it, but we are not interested here in the amount of power we are supplying to the resistive load, we are researching resonant frequency effects. So if you were to plot your results for all speeds of N they would follow a fixed relationship, any resonant effects would be anomolous and not follow the line of best fit.

You can easily measure the RPM of the drive shaft using a laser tachometer:

Clarke CT1 Digital Laser Tachometer - Machine Mart

laser tachometer | eBay

Much cheaper on ebay

Tesla turbine made from hard drive platters. - YouTube

Reflective tape placed on the rotating shaft (painted black for accurate readings) gives you a digital readout of complete rotations, 360 = 1 cycle

So if the shaft was spinning one complete 360 degrees in 1 Second the frequency of the shaft would be 1 Hertz, however because your alternator has 3 phases per complete 360 degree revolution (120 degrees apart), you have to realise that there are 3 sinusoidal waveforms being generated that are superimposed, one is 120 degrees ahead, and one is 120 degrees behind.

If you were now to add a second alternator to the same shaft, but alter it's relationship to the driven turbine RPM speed by using a step up or step down gearbox, you would be able to run both alternators in a fixed harmonic relationship, because a harmonic is achieved everytime you double the frequency. So the simplest way to do this is by using a pulley and belt with a ratio of 2:1, which would mean that for every 360 degree rotation of the shaft, your second alternator would spin 720 degrees, or in other words at twice the frequency of the first alternator. This relationship is fixed to shaft RPM, unless you change the pulley ratios (circumference of pulley), so it is not only fully flexible, it is fully accurate.

And the beauty of this system is, that you control the frequency of AC generated simply by opening or closing the valve on your tap. If you were for example to set up an electrode boiler with 2 positive plates and a common ground, with each alternator wired to a different positive electrode, you would be superimposing two harmonic frequencies on the common ground electrode, and generating two separate frequencies that are harmonically related in the fluid between the respective positive electrodes.

You can of course use oscilloscopes to also monitor the waveforms, it is good scientific practice to take as many measurements as is practically possible, and when your researching an anomolous effect it is the only course of action that complies with the scientific method, and gives results that can be analysed. The temperature plots over time, either positive or negative, will show you any anomolous effects because they will deviate from the control plots.

Hope that helps

Rob

P.S. If you go to the trouble to construct this relatively simple apparatus, you also now have a fully operational power generation plant in your home that runs off water pressure!

http://www.energeticforum.com/renewa...ication-2.html

[PhysicsProf]

Thanks for the information, Rob! a lot of good info.

I'm wondering about a simple gas-powered-motor generator, say 800 Watts max, that one can buy for about $140 here. Is the output frequency controlled by a governor on the gas-engine?

[AhuraMazda]

Variable Frequency Inverter

If we cut through the chase, here is a basic inverter that works:

[wrtner]

Thanks for the information, Rob! a lot of good info.

I'm wondering about a simple gas-powered-motor generator, say 800 Watts max, that one can buy for about $140 here. Is the output frequency controlled by a governor on the gas-engine?

I doubt that such a controller would be accurate enough. With the
basic Peter daysh Davey device (i.e. not this one), tuning is crucial.
I expect it is crucial in this case also.

Earlier on in this thread there is a design for starting with DC, getting into
an inverter and putting in an adjustment for output frequency.
Paul-R

[Michael John Nunnerley]

frequency mixing and hitting the right point

So how do you "vary your AC frequency "? I'm interested, evolving...
I've done some tests with two coils running at different frequencies (from signal generators) then watching the beat frequencies using a pick-up coil... quite interesting alright!
Wondering if a guy could do this with a Tesla coil... So many avenues to pursue!

Well if you would like to talk about that it is a pet subject "using two different frequencies". When this is done you can hit a point that generates a wide band of frequencies which do not trail off in power as the frequencies go up "the stair effect". When you get this the energy in those frequencies when added up are infact greater than the original input of the two frequencies.

I am on skype centraflow or e-mail centraflow@gmail.com

Mike

[TEKTRON]

Thanks for the information, Rob! a lot of good info.

I'm wondering about a simple gas-powered-motor generator, say 800 Watts max, that one can buy for about $140 here. Is the output frequency controlled by a governor on the gas-engine?

Yes, it is. and it is not very stable under varying loads. Just dropped in. Ive not been keeping up with the thread, but I saw a question I could answer. Good luck guys

[PhysicsProf]

Well if you would like to talk about that it is a pet subject "using two different frequencies". When this is done you can hit a point that generates a wide band of frequencies which do not trail off in power as the frequencies go up "the stair effect". When you get this the energy in those frequencies when added up are in fact greater than the original input of the two frequencies.

I am on skype centraflow or e-mail centraflow@gmail.com

Mike

Good to hear from you, Michael -- I have a great deal of respect for your work, and have discussed it with Andrew M. I hope to get back to this in more detail fairly soon -- now involved in two other projects! I've thought of ways of bringing in the two freq's... in these projects also!

Thanks for your comment also, Rob.

[PhysicsProf]

For several weeks, I have been experimenting with heating measured amounts of water to determine output energy, using a control resistive heater; also with a few configurations of the "Davey-type Sonic Boilers". Time to report some results and what I've learned about calorimetry controls.

Nerzh Dishual is abreast of the situation as well, and has been doing related experiments in Brest, France. (Sounds like a great place to visit, Nerzh! I've been to France quite a lot in years past, but not to your town yet...) Hopefully he'll describe some of those tests and experiments which he has done.

The method is quite straightforward, applying the equations:
Qheating = 4.186 J/g-degC * mass of water heated * (Tfinal - Tinitial)

and for water vaporized, we have:
Qvaporization = 2260 J/g * mass of water vaporized.


I have used different set-ups; two are shown in the attached photos. One involves an immersion heater and 2 liters of water. The other uses an off-the-shelf electric kettle -- I ended up buying three of these for these tests. Thanks to Nerzh for suggesting this method to me privately.

Mains power is monitored by two energy meters (“kill-a-watt” meters at present); one measures the energy consumed in kW-hrs, and the other the power being consumed during the run. A stop-watch is used to keep track of the time required for the kW-hr monitor to go from zero to 0.01 kW-h (=36000 J). That is the sensitivity of this meter; but I have another on order that will go to 0.001 kW-h (3600J).

The control water heater, a simple resistive coil (see photo) is rated at 300 W and runs at 301-303 W, and requires 1m58 to 1m59 seconds to use 0.01 kW-hr; which is all consistent, so the meters check out and agree.

I'll now jump ahead to data acquired today, to make a long story short!
These data acquired with the set-up shown in the photo with the off-the-shelf electric kettle for the control experiment. (Note that a small "Davey device" can be placed in the SAME vessel, to permit direct comparisons of temperature-rise in the water etc.)

I have a 500 ml graduated cylinder which I filled twice in order to have 1000 ml of water in the Proctor-Silex vessel. (I marked the level of the 1 liter on the vessel, whose own mark was significantly off -- so I'm glad I measured independently with a grad-cylinder!)

I measured the temperature rise after adding 0.01 kW-hr (=36000J) to the water, as measured by the kW-hr meter, and after stirring the water with a plastic spoon right after the run was terminated. I used three temp-probes:
Fluke 52, TES 1310 (also type K) and a Taylor 9842 (yellow + stainless steel digital device shown in the Feb 2012 photo).

I found that the TES and Taylor digital thermometers agreed reasonably well on temperature rise at 8.3 +/- 0.1 deg-C, whereas the older Fluke thermometer (which I had borrowed) seemed way off and gave a temp-rise of only 6.5 deg-C (average).

For the temp rise of 8.3 deg C for 36kJ input electrical energy, we find:
Qinto-water = 4.186 * 1000g *8.3C = 34.74 kJ.
Efficiency = 37.74/36 = 97%.
Consistent with unity as expected, since ohmic heating is simply dissipated into the water in the electric kettle. A convenient control!

The older Fluke thermometer, OTOH, suggests a temp rise of only 6.5 deg C and an efficiency of 76%... it needs to be re-calibrated; or returned to the owner in this case! I do like to have redundant temp measurements, and will continue to do so. (I also have an infrared temp probe, but find that this gives variable readings within seconds of readings. I think this stems from trying to use the IR probe to measure water temps -- when water is transparent.)

I performed the same experiment in 1 liter of water in a Kaloric electric kettle, with the same result -- 8.3 deg C for 36kJ input electrical energy, and an efficiency of approximately 97%. This vessel has about twice the interior volume and so will permit larger test-devices in future runs.

[PhysicsProf]

I wish to emphasize the following I've learned from these control experiments:

1. Have redundant (preferably at least 3) temperature-probes, to check against each other to make sure there is not a problem in temperature measurements (as I found with the old Fluke K-type that I had borrowed).

2. I also use two energy-monitoring meters as described in post #1, and I've ordered one more. Again, its important to check the input energy by redundant measuring devices.

3. The water needs to be stirred vigorously after (or during) a heating run, before taking temp measurements. Even so, it seems wise to have the temp-probes in different locations, and to compare results obtained with the two probes.

4. A "standard" electric kettle makes a convenient control and gives efficiency near unity. (I have three of these now, in different sizes.)

5. Record data and questions in a bound log-book.

6. Measure water volume using a graduated cylinder -- I have a 500 ml graduated cylinder and some smaller ones. I found that the electric kettle markings are not completely accurate, when I filled each kettle with [2 times 500 ml] from the graduated cylinder.

I hope this is helpful to others.

[wrtner]

I wish to emphasize the following I've
learned from these control experiments:
Have redundant (preferably at least 3) temperature-probes, to check
against each other...

This is fine if you are trying to determine a physical constant to
three decimal places. It is expensive and complicated.

The bottom line is that, at the moment, we need to know two
things:
1. Is the equipment runing at a COP > 1
2. Roughly what that COP might be.

That's all.

There is no need to put people off with all that complexity.

[PhysicsProf]

This is fine if you are trying to determine a physical constant to
three decimal places. It is expensive and complicated.

The bottom line is that, at the moment, we need to know two
things:
1. Is the equipment runing at a COP > 1
2. Roughly what that COP might be.

That's all.

There is no need to put people off with all that complexity.

I beg to politely differ. Based on the data I presented above, one of the temperature probes -- a borrowed Fluke Type-K thermometer -- turned out to be WAY OFF! And it slowed my experiments way down also, until I checked with other temp-probes and determined the problem.

The main problem was that the (Temp-final minus Temp-initial) was way off, so the calculation of efficiency was way LOW. The redundancy is to MAKE SURE THE INSTRUMENTS ARE PROPERLY FUNCTIONING, not to " determine a physical constant to
three decimal places."

OK?

Also, it is not expensive -- I paid $11.96 (including shipping) for this:
Taylor 9842 Commercial Waterproof Digital Thermometer
Sold by Amazon.com LLC (Amazon.com)

Worked great! I checked it with a Type-K thermocouple thermometer from China that cost me $11.66. (Much cheaper than a Fluke!)
Ebay, New K Type Digital Thermometer Temperature Sensor
Price: $11.66, TES 1310.

[quantumuppercut]

Nice work professor,

I like your approach, slow but solid. Suppose we just jump to the bad fluke and depends on those data which gives 76%, it would be unfair. What even worse is if that bad reading was 97%. lol

This is an example how the community can gain reputation from mainstream, succeed or not.

[PhysicsProf]

Thank you, quantumuppercut:

Nice work professor,

I like your approach, slow but solid. Suppose we just jump to the bad fluke and depends on those data which gives 76%, it would be unfair. What even worse is if that bad reading was 97%. lol

This is an example how the community can gain reputation from mainstream, succeed or not.

Well said.

Today I did some testing with a build I did using 2 "bells", chemistry crucibles with a hole drilled in the each base, joined together at the bases with a nylon bolt + nylon nuts and spacer. See photo on the right. The distance between bells is approx. 1 cm, OD of the outer bell is 6 cm. The pitch of each bell when struck is approx. B-flat (compared with the tune on my piano), roughly 240 Hz. The mains provided 120 V and the input power was measured by two "kill-a-watt" meters in series -- approx. 1200 W during operation in water.

I ran with the bells until the energy meter registered 0.01 kW-hr (= 36,000 J) input energy, then I took temp. measurements.

For the control -- described also above -- I used the built-in coil of the electric kettle, shown in the photo on the left.

The water volume was measured at 1222 ml using a graduated cylinder.

I observed temp rise of 7.0 deg C for 36kJ input electrical energy; so we find:

Qinto-water = 4.186 * 1222g *7.0C = 35.8 kJ.
Efficiency = 35.8/36.0 = 99%.

Consistent with unity... can't get much closer. Control run with the SAME water, using the built-in resistive coils in the Kaloric vessel, gave the same result...

Overall, to be expected -- but I sure would like to try a WORKING Davey device! I'm still trying...

[evolvingape]

You might find this video interesting Professor:

Forced Oscillations and Resonance | MIT Physics Lecture

A nice demonstration at about 10 minutes helps visualise processes occurring in resonant systems.

I am just going to add this link as it relates to the air spring heater idea I talked about a while back, the idea being that air is compressible and at resonance has a very large amplitude. This should focus the temperature increase over a small area in contact with the water, which is incompressible.

Weekend Project: Fire Piston - YouTube

Rob