Explanations

[charly2]

Hi Jim, your speed table ok, but the main frame runs very slow at about 18 rpm.
The pieces I was talking about are 4.75Ø inches.
It is not finished but I made some tricks to emulate the mising parts and make it turn for few seconds, but synchrony and ratios are important to keep it run. So all parts are needed for a long test.

[rlortie]

jim_mich

Your hand book chart is as stated for cast iron and is questionable regarding usage and conditions.

First example is the flywheel or dampener on an automotive engine capable of 8,000 rpm or more. Your chart would put a limit of 3,360 RPM on a six inch dampener found on the front end of a crankshaft.

A synchronous 60 cycle electric motor with two poles turns at 3600 RPM and @ 1800 with four poles. Such motors are abundant and used on everything from table saws to water pumps.

Even my 14" abrasive wheel metal chop saw turns 3,800 rpm with blades rated to 4,500 rpm. I have never had one fly apart yet!

Our man here (in question) owns a Dremel router, if its the variable speed one it is advertized at 35,000 RPM,

As for the avatar; it reminds me of a 33-1/3 record album that was left in the sun while in the back window shelf of an automobile.

Ralph

[jim_mich]

As I stated, there are seven pages in the book discussing this subject of flywheel design. The chart from which I took the values assumes a SAFE speed for flywheels to be 100 feet per second rim speed. Tests of cast-iron flywheels by a professor C. H. Benjamin determined that most cast-iron flywheels burst at a rim speed of about 395 feet per second. These chart numbers included a safety factor since the energy source of the era was usually steam engines, and there was always the possibility of over-speeding the equipment. The chart was provided by the Fidelity & Casualty Co. of NY, and I'm sure they were more interested in safety than efficiency.

Ralph, your 14" chop saw, running at 4,500 RPM would have a rim speed of 274.889 feet per second, which is well under the 395 feet per second bursting speed of cast-iron.

What is the diameter of a Dremel tool motor, maybe two inches? That puts its rim speed at about 305 feet per second, again under the 395 feet per second bursting speed of cast-iron. Note that modern steel alloys are much stronger than cast-iron.

Ralph, my original point was simply that a large wheel, of the size most forum members attempt to build, would explode from CF at 1500 RPM. It was an attempt at a quick post to illustrate my point that a 1500 RPM speed mentioned by charly2 was an unrealistic speed. But as usual, Ralph, your points of contention are not based upon true engineering analysis, but instead you base your thinking on some sort of gut feeling not backed up by true engineering facts.


I'll crawl back into my hole now and pull a rock over my head.

[bobriddle]

@All, for general information, the wheel I'll be building, if it spins at 30 rpm with a diameter of 40 inches is something I would be satisfied with.
Bessler did say he managed 60 rpm. Since gravity has a base value of 9.8 m/s, if a wheel travels at 4.9 m/s rim speed, it's diameter would need to be about .78 meters or slightly more than 2.5 feet.
Myself, I consider that if a lever falls with a weight on it, it will be accelerating from 0 and will not accelerate for 1 second unless the wheel is rotating at less than 30 rpm which would dimenish it's maximum velocity. the actual forces being worked with and would limit the maximum rpm.
What is accepted in physics is that the acceleration of a falling object while slower when following a curved path will still have the same velocity relative to the vertical drop. This would allow the height a weight is dropping to determine it's maximum velocity and the potential force it can generate when used in conjucntion with a lever.
The wheel I am pursuing will not have the weights working together as I will need more experience before pursuing more complicated designs and possibilities.
I have previously had a shop that when I was unable to work because of medical problems i had to give up. I still have my tools and after Christmas should be set up in a shop again.
Here is a link to some of the tools i have available. Since I am back at work now, I will buy myself some more tools as they will help me to enjoy my hobby. And this will give me a chance to ask the Veteran's Adminsitration to change it's position and consider a hearing loss a disability as any other impairment that limits a person in pursuing their own life. It is one of my motivations for having stayed the course.
Will be glad when I can have a decently equipped wood shop :-)
Jim

http://s979.beta.photobucket.com/user/b ... 9060262351

[rlortie]

jim_mich

This is the second of recent time you have responded in a defensive if not vindictive manner, first to James and now me, stating that you would crawl into your hole and pull a rock over your head,

I stated 'usage and conditions' and got my facts from items on hand and engineering facts placed on the item specifications. My purpose was for enlightenment for those with less knowledge. I did not mention that a 96" jet turbine engine blade breaks the sound barrier.

In all you appear to be impatient, disgruntled, and looking for or interpreting a response as only negative to your well meant and received input. Your input is always appreciated and no one to my knowledge is intentionally trying to tear you down.

Are you in good health, having personal problems or is it just your apprehension of not finding a runner in the near future? I am not a doctor but as a peer and friend in similar pursuits, I only wish to advise you that you seem to be a little "on edge" and wondering if you are in need of help in what put you there.

Ralph

[jim_mich]

I get in a bad mood when I read insulting postings by Jim_Lindgaard, also known as bobriddle, also known as john, also known as P-Motion, also known as to.late, also probably other reincarnation by this same troll. He just rubs me the wrong way by his negative bashing of forum members. It gets me in a bad mood. Then I see something like a wheel possibly rotating at 1500 RPM, I feel a need to correct an obvious impossibility. Then you, Ralph, start defending such nonsense by posting things that seem insulting to my intelligence, and I get a little testy.

[rlortie]

jim_mich,

If it is of any help, we all have to put up with certain members, some I have put up with on other forums longer than we have had to endure them here on Besslerwheel.

No! my intent was not to defend such nonsense, no difference than your input regarding the fixing of James's dead links that he chastised you for, I certainly had no intent of insulting your intelligence, you got your information from a reputable source as I did mine only for expanding on your input.

As for offering help regarding your bad mood, please rest assured that you are not alone, you have support and we all know what the little red and green dots are for. I admit that it only cools their heals for a short while once banned before they show up again, it does give us a little rest briefly.

Testy, testier and testiest are all formidable words and ] are signs of irritable and touchy promoting lack of patience. suggest you count to ten and analyze the input of how a responding post is worded.

When I first came on-board, Bill McMurtry was doing a fine job as watch dog policing this forum and helped keep the sock puppets in check. Apparently since the removal of the IP icon this job has been a little harder to keep track of. Either that or the man I once considered the sheriff of our digital community has semi_retired.

In the past, you and I have had our debates which seemed to add incitement and participation of other members. With philosophical reasoning, I always thought they were good for motivating values, concepts or principles of an individual group. I did my best to keep these debates in an analytical bases and avoid them from turning personal.

By the way, you are a couple of pseudonyms short, one more I can recall is BAHammer. a ploy on his part to ridicule ABhammer

Like a poltergeist every time Jim lingaard is bumped from this forum he returns with a new alias, it only takes about three posts to figure out he's back.

I respect you as a peer with intelligence, and my integrity does not allow bashing (criticizing) or chastising a fellow peer in public. If I have reason or due cause it will be face to face or at least by private mail.

Ralph

[bobriddle]

I'll leave you guys alone and after I am finished with the project I am working on, you guys can get together with AB Hammer and say how you knew it all along. 8D

Jim

[charly2]

Sorry, I should not have to start writing about this nonsense element if I was not going to fully explain. I now realize it can be misunderstood or even irritating.
I'm a mechanical engineer, and in school I learned very good all physic laws, I'm sure it doesn't break any law. I do know how it works but I can't explain to myself where the extra energy (or work) is coming, it is a close loop and gravity is not involved, simply I don't understand and is a bit frustrating, I just have a guess.
I'll post it when I'm ready to do it, then perhaps we can discuss about it.

[path_finder]

An interesting document about the practical limits of the flywheels
http://drgoulu.com/2007/04/03/les-roues-du-tgv/
But in french. My translation in english:

The wheels of the TGV (High Speed Train)
Published 03/04/2007 by Dr. Goulu

The TGV(HST) beat its own speed record today by reaching almost 575 kph, just a little less than Japanese Maglev with magnetic levitation (581 kph). At the speed of 575 kph, that is 160 m/s, a 920 mm wheel (weighing in 600 kg) makes 55 turns per second (!). Can she turn even faster?

I quickly modelled a steel rough wheel of train of standard construction with SolidWorks and calculated with CosmosWorks the effect of a load of 12 tons corresponding approximately to the weight of an engine divided by the number of its wheels. The result in the stop state is below: the constraint in the contact of the rail is approximately half of the elastic limit of the wheel:

--- first drawing (blue wheel) ---

At 55 turns per second, the centrifugal force thus changes completely the deal and gives this:

--- second drawing (light green wheel)

The constraint due to the contact with the rail is hardly more brought up than that due to the centrifugal force (we shall speak about the sign hereafter). The corresponding safety factor is no more than of 1.6 instead of 2.1 in the stop state: in fact the wheel is closer to explode because of its speed than to crash under the weight of the loco!

If we look what takes place in the zone of contact with the rail, we see that the constraint is in compression (blue zone), while in all other zones the constraints are in traction under the influence of the centrifugal force.

--- third drawing

The compression due to the 12 tons weight of the train is extremely localized: in some millimeters of the zone of contact, it is as if there was not a rail anymore. Every point of the bandage of the wheel passes 50 times per second of a strong traction in a strong compression and vice versa within a thousandth of second: combined with the vibrations and the shocks, they are ideal conditions for the fatigue of materials...

A safety factor of 2 on the wheels of the TGV(HST) in 575 kph is sufficient for a record, but not for a supposed train to roll hours a day to this speed. If the commercial trains reach one day this speed, they will have very "high-tech" wheels, or no more wheels at all.

---------------------- end of the traduction --------------------

I shall add an important point regarding the outer rim of the flange: coming from an epicycloidal effect, all points of the outer rim of the flange go backward 55 times a second and immediatly are accelerated at 1.150 kp/h (twice the speed of the train).
You can imagine the constraints on the materials at that place.

[eccentrically1]

Very informative.

[bobriddle]

An interesting document about the practical limits of the flywheels
http://drgoulu.com/2007/04/03/les-roues-du-tgv/
But in french. My translation in english:

The wheels of the TGV (High Speed Train)
Published 03/04/2007 by Dr. Goulu

The TGV(HST) beat its own speed record today by reaching almost 575 kph, just a little less than Japanese Maglev with magnetic levitation (581 kph). At the speed of 575 kph, that is 160 m/s, a 920 mm wheel (weighing in 600 kg) makes 55 turns per second (!). Can she turn even faster?

I quickly modelled a steel rough wheel of train of standard construction with SolidWorks and calculated with CosmosWorks the effect of a load of 12 tons corresponding approximately to the weight of an engine divided by the number of its wheels. The result in the stop state is below: the constraint in the contact of the rail is approximately half of the elastic limit of the wheel:

--- first drawing (blue wheel) ---

At 55 turns per second, the centrifugal force thus changes completely the deal and gives this:

--- second drawing (light green wheel)

The constraint due to the contact with the rail is hardly more brought up than that due to the centrifugal force (we shall speak about the sign hereafter). The corresponding safety factor is no more than of 1.6 instead of 2.1 in the stop state: in fact the wheel is closer to explode because of its speed than to crash under the weight of the loco!

If we look what takes place in the zone of contact with the rail, we see that the constraint is in compression (blue zone), while in all other zones the constraints are in traction under the influence of the centrifugal force.

--- third drawing

The compression due to the 12 tons weight of the train is extremely localized: in some millimeters of the zone of contact, it is as if there was not a rail anymore. Every point of the bandage of the wheel passes 50 times per second of a strong traction in a strong compression and vice versa within a thousandth of second: combined with the vibrations and the shocks, they are ideal conditions for the fatigue of materials...

A safety factor of 2 on the wheels of the TGV(HST) in 575 kph is sufficient for a record, but not for a supposed train to roll hours a day to this speed. If the commercial trains reach one day this speed, they will have very "high-tech" wheels, or no more wheels at all.

---------------------- end of the traduction --------------------

I shall add an important point regarding the outer rim of the flange: coming from an epicycloidal effect, all points of the outer rim of the flange go backward 55 times a second and immediatly are accelerated at 1.150 kp/h (twice the speed of the train).
You can imagine the constraints on the materials at that place.

Hope you don't mind my mentioning that my Norwegian father told me that there are critical stages in rotating machinery. I haven't seen this mentioned.
An example is a steam turbine which can have 3 critical stages which can resault in catastrophic failure. The reason I given and doubt because ab hammer said my dad is an idiot who knows nothing said that when the velocity of any part of a flywheel exceeds the speed of sound that it's harmonics changes. And with something like a steam turbine and the large diameter rotors they use, the amount of mass effected by the velocity being over or under the speed of sound can cause such a vibrtion that would destroy any turbine if it did not quickly accelerate through those critical stages.
I'm not an engineer or anything just cause I went to school for engineering, just repeating what my dad said.
And ab hammer being the nice person he is has often told me he would teach my dad engineering if he had 4 years to study under him. While that is very nice of ab hammer, my father retired from being a field engineer and a business manager for an industrial repair shop. Still not acceptable by some standards :-)

edited to add; a rotor that is about 6 feet indaimeter will have a rim speed of apporoximately the speed of sound at 3,000 rpm. Since electricity is generated at an rpm of 3,600, most turbines and possibly the generators they drive will have parts of them exceeding the speed of sound. The question is, could a sonic boom undo mechanicl components ?
Haven't seen it happen yet but did see my dad come unglued when an operator stopped a generator when it was accelerating to speed. it started vibrating severely so he quit accelerating it while it was sitting on (running at) a critical rpm.
Still, wish I had some worth while experience or knowledge but must remain a troll and build my wheel. I think it's kind of sad that people who support Bessler are afraid of spending a few dollars to check out some of his mechanics.
he probably wasn't as smart as you guys, why he built and you only discuss his work. it's not really worth repeating, is it /

[murilo]

My ROUGH 2 cents:
not sure if machines have 3 or 'n' danger stages, but as I know every set have their specific resonance, as an assembly with several together parts.

The resonance is cyclic and natural as any other wave system, in presence of 'forces'.

If these installed waves are summed to the incoming vibrations the result is a catastrophe! Be sure... the stuff get uncontrolled and get down in pieces.

More than 2 times I lived this phenomenon in BOATS, when both frequencies found same 'form' and 'time', with multiplied effects! The trained pilot has to cut out the motor, when one will observe for some seconds all residual vibration coming down.

TC!
Murilo

[bobriddle]

Murilo,
I think one thing people over look is that cars have harmonic balancers other wise tbe vibration from combustion could damage the engine.
Like Bessler using a 3 weighted pendulum, it would act as a damper. On a side note, necause Bessler was religious, his using 3 weights could be his way of acknowledging the trinity.

Jim

[ruggerodk]

Carbon-fiber composite rim Flywheel:

...has a high-performance rotor assembly that is sealed in a vacuum chamber and spins between 8,000 and 16,000 rpm. At 16,000 rpm the flywheel can store and deliver 25 kWh of extractable energy. At 16,000 rpm, the surface speed of the rim would be approximately Mach 2 - or about 1500 mph - if it were operated in normal atmosphere. At that speed the rim must be enclosed in a high vacuum to reduce friction and energy losses. To reduce losses even further, the rotor is levitated with a combination of permanent magnets and an electromagnetic bearing.

http://www.beaconpower.com/products/about-flywheels.asp[/quote]