I will attempt to answer any questions you may wish to ask to the best of my ability.
string will apply restoring force to the body when it is not in rest position. this applies to both directions
force pairing would suggest that the body would counter rotate when the rotor arms are accelerating which it does not.
I understand your comments concerning the string, but the amount of restoring force in the string would have to be quite considerable for it to produce the end reaction
, and as I have earlier mentioned, the device works equally well when placed on a thrust bearing so that there is no restoring force at all since it is not attached to a string.
If you hold a slinky with an outstretched arm and allow it to fully extend so that the end of the slinky is around a foot from the floor, when you let go of the slinky you will observe that the bottom of the slinky 'levitates' for a moment and defies gravity.
The time of the counter rotation can be varied depending on how far the magnets are placed down the tube, i.e. with no magnets the body will counter rotate many turns. It is the collapse of the torque reaction when the magnetic interactions begin that enables the swinging process.
However, we can use your four seconds for a thought experiment. Imagine we take the device into deep space where the external friction is approx -22kg/m^3.
As you have noted, the body's counter rotation will last for four seconds,
A thrust bearing, as you have noted, will apply friction to the device as long as the device is moving. A bearing can apply resistance to movement, but to the best of my knowledge can not exert a restoring force to the device.
As for usefulness, please refer to the thought experiment, i.e. transfer of energy/momentum from battery to the device.
Yes, acceleration of rotor arms every quarter turn after load collapse.
You are probably going to have to draw a diagram to clarify what you are talking about here.If you cannot visualize what will happen without the magnets, I don't think the diagram is going to help.
Also, magnetic interactions have nothing to do with why the body portion comes to a stop in your video.This statement is illogical; if the magnets are taken away then it is impossible for the body to remain in its rest position. Also, if you are to make such as statement, could you at least add support to your argument. However, at least we have made progress in that you do recognize that the body does stop.
Why does it matter if it is a restoring force? It still applies a torque to the device which is where it gets its net angular momentum before you turn it off.The lack of a restoring force is everything - for the body to remain stationary, it is unable to overcome the friction of the thrust bearing.
"load collapse" is not a phrase that has any meaning here.Also, you say "yes" to it being the initial acceleration, but then you say "every quarter turn" which implies you are using "acceleration" to refer to the jerky part of the motion.This pedantic manner is helping no one. I do not wish to be like two bald men fighting over a comb. So, if we could move on and maybe find some common ground.
Therefore, if I can ask a question, is it theoretically impossible for the rotor arms to accelerate (in the jerky bit) without applying an opposite force to the body?
Since there have been no objections I will continue.
But as you can see in the video, the body does not counter rotate. This means that there is a counter force acting on the body which stops it counter rotating. There is a slight oscillation in the body but, if we refer to the slinky experiment, we can use statics to explain this process.
Since there have been no objections I will continue. We are at the point where the rotor arm has just enough momentum left to move across the body magnet. The magnetic potential energy in the body magnet and the rotor magnet is released and the rotor magnet is accelerated down the tube, which you can hear on the video. The motor is now free to accelerate and again, using classical physics, we know what should happen. As the rotor arms accelerate a force should be applied to the body causing the body to counter rotate. But as you can see in the video, the body does not counter rotate. This means that there is a counter force acting on the body which stops it counter rotating. There is a slight oscillation in the body but, if we refer to the slinky experiment, we can use statics to explain this process. I will pause for the moment. If I receive no further objections to the above then I will continue to the next set of interactions.
And the thrust bearing?
So it's not the string?
Look, I know how you feel, I've been there. It is difficult to think that such a simple device can achieve what you see on the video.
Now you will have to take my word for it, it is NOT the string. I have checked, double checked, and triple checked it.
On a positive note, since the diagram was of a device suspended by a piece of string, I no longer have to supply it.
As stated earlier, the body cannot move since it is effectively pushing against itself.
Always remember that a thrust bearing will apply an equal amount of friction in either direction.
So, as the magnets are forced together, load is applied to the motor. If we look at armature reaction, we will see that, due to the load, the main field flux lines will distort and shift the Magnetic Neutral Axis in the opposite direction to rotation. As stated earlier, the body cannot move since it is effectively pushing against itself. It is easier to visualize the movement of the M.N.A so that when the tube magnet accelerates down the tube, load will rapidly drop which will cause the main field flux lines to shorten and the M.N.A will now move in the direction of rotation. This will drag the body in the direction of rotation.We now have the required situation where the body is attempting to move in the direction of rotation. At the same time the rotor arms apply the counter force as they accelerate. So there you have it. A very simple device. Everything that has been explained is known and can be easily accessed. All the information can be easily found on the internet or in any electrical engineering textbook.I am amazed at the mention of dean drive. You make reference to a device that famously did not work because it was suspended from a string (i.e. no contact with the ground) and yet almost in the same breath you are arguing that the only reason the device works, as in the video, is because it is suspended from a string?Always remember that a thrust bearing will apply an equal amount of friction in either direction. May I suggest that you now do some easy searching so that you may understand more clearly what I have stated. The various websites etc. will explain it in far more detail than me.
Because of the need to push past the repelling magnetic field of the body magnet, the power supply settings are such that if I were to remove the body magnet, the motor would accelerate very quickly and hence so would the body. The body would become snagged in the power input wires so at the moment it really isn't a viable option.
Because of the need to push past the repelling magnetic field of the body magnet, the power supply settings are such that if I were to remove the body magnet, the motor would accelerate very quickly and hence so would the body. The body would become snagged in the power input wires so at the moment it really isn't a viable option. Thank you for the feedback though, and if you or anyone else has any more suggestions, please feel free to air them. We do, however, have a set of interactions that we can now look at, and don't forget we are starting with a deceleration (it is very easy to look at this back to front). If we say the magnets are M: the Field Flux is FF the Body is B and the Rotor Speed is NWe now have.. -N + (M+-M) + (FF+-FF) + (B+-B) + N = 0 Or in a simple visual sense - a five ball Newton's cradle. The brackets are the three center balls. So, the -N ball decelerates, the three middle balls remain static, and to conserve (transfer) momentum, the N ball must accelerate. I know this is a very simplistic explanation but it does conform with everything we know.
P.S. I have not claimed to be breaking conservation of momentum.
I did say that a battery was fitted.
Interesting.
I wasn't intending on entering it for any physics prize. You're missing the point here. If you are of a certain level of physics, you do not need me to help you with the explanation (or at least shouldn't). There are people, however, who may not be in that position. The formula is intended to help with the explanation and therefore must match it. Since I have used 'the body' in the explanation, so 'the body' is used in the formula. Any reasonable person would understand this. If the formula can help a single person (and I mean literally one person) to understand how the momentum transfers through the system then I am a happy man. However, on a technical basis, you are correct. Anyway, have you got anymore comments on your 'string theory'?P.S. I have not claimed to be breaking conservation of momentum.
5) Transfer of momentum as observed, device moves in the direction of the rotor arms.
If you turn the power off when the device has returned to its rest position at exactly the moment the tube magnet begins to accelerate down the tube when facing the body magnet, the device will not move, so there is no stored energy in the string at this point.
If I can return to the thrust bearing, a thrust bearing can only apply friction, it cannot operate as a spring.
I think the string is acting like a spring, storing up energy and releasing it and the earth is yielding up some angular momentum to the system through the torque that the string has.I totally agree with your comments on winding a string. We can all remember winding a swing when we were children and then letting it spin as it unwound. This is what Jim Davis is referring to but, of course, we need to wind to unwind.I will go through the video in detail :-1) The body is at rest and the nearest tube magnet has been pushed down the tube to allow for starting.2) Power is switched on, the rotor arms accelerate and the body counter-rotates, winding the string.3) Jerk cycle takes effect, resulting in no counter-rotation of the body.4) The string now unwinds, so the device swings back and forth (string winding and unwinding) until it returns to its rest position (i.e. string is not wound).5) Transfer of momentum as observed, device moves in the direction of the rotor arms.If you turn the power off when the device has returned to its rest position at exactly the moment the tube magnet begins to accelerate down the tube when facing the body magnet, the device will not move, so there is no stored energy in the string at this point.If I can return to the thrust bearing, a thrust bearing can only apply friction, it cannot operate as a spring. Have you considered suspending your device from two strings, parallel to each other and about a centimeter apart? If, after you turn your device on, the strings twist around each other, you will know that the stings are applying a torque when the device is turned off as they unwind.Thanks for the suggestion. I have referred to it in my earlier remarks.
We can now briefly look at the thrust bearing. In the jerk cycle, as the rotor arms accelerate, the body is unable to counter rotate because it is unable to overcome the friction of the thrust bearing. When the power is switched off momentum transfer takes place and the device moves in the direction as the rotor arms overcoming the same amount of friction.Therefore I feel it reasonable to conclude, that a force is acting on the body which cancels out the force applied to the body when the rotor arms accelerate.
All of the energy/momentum that the body requires is provided by the power supply.
the string is not wound when the power is switched off.