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Author Topic: TPU - General Discussion  (Read 350372 times)

BEP

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Re: TPU - General Discussion
« Reply #195 on: October 09, 2007, 04:09:03 PM »
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« Last Edit: October 12, 2007, 03:53:56 AM by BEP »

EMdevices

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Re: TPU - General Discussion
« Reply #196 on: October 09, 2007, 04:24:21 PM »
All

Have you wondered why you need the DC bias? 

If you've built oscillators and amplifiers you will understand.

EM


EMdevices

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Re: TPU - General Discussion
« Reply #197 on: October 09, 2007, 04:42:11 PM »
Here's the magnetostriction chart again, showing the changes in the driving current producing the strain or change in length.

EM

Esa Maunu

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Re: TPU - General Discussion
« Reply #198 on: October 09, 2007, 05:10:54 PM »
@Esa Maunu
Quote
If you use a helical coil around the magnetostrictive rod, it does not create linear lenght changes for this rod.
Helical coil creates a twisting  effect and torgue for magnetostrictive rod, this phenomena is also known as Wiedemann effect. ...

Esa,  I disagree.  The magnetostriction phenomena involves a lengthening of the material ALONG THE ORIENTATION OF THE MAGNETIC DOMAINS, and I'm sure you know that a solenoidal coil produces a AXIAL magnetic field, hence the lengthening happens along the AXIS or the length of the rod.

The Wiedemann effect is something else, but quite related.  that's where you impose a radial external magnetic field at, for example the middle of the rod, like I showed in my previous postings. 

EM

It depends if you use helical coil or just solenoidal coil. In your picture it looks like helical coil. but even if you use solenoidal coil and apply a current in to this rod, you can get a twisting effect. On the other hand i don`t think that this produces OU. But who knows..

http://en.wikipedia.org/wiki/Magnetostriction

Esa

BEP

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Re: TPU - General Discussion
« Reply #199 on: October 09, 2007, 05:55:15 PM »
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« Last Edit: October 12, 2007, 03:52:47 AM by BEP »

EMdevices

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Re: TPU - General Discussion
« Reply #200 on: October 09, 2007, 06:29:22 PM »
Quote
As far as which direction it goes - both. The only question in my mind is which one provides the most movement...

BEP, make sure you push the material into SATURATION.   If you push it one way into saturation and then reverse the current you will not be quite at the same point on the MAGNETISATION CURVE.     Hysterisis my friend, keep that in mind.

EM

EMdevices

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Re: TPU - General Discussion
« Reply #201 on: October 09, 2007, 06:29:35 PM »
Here's a better operation Region on the curves.

This is the principle of Amplification.

With a small signal change (d) we create a larger strain (S)

EM

P.S.   I'm not going to give out any more clues from here on out.  I led you far enough.  I'm not sure if people have the necessary skills to do this or not, a few of you I'm sure have what it takes.   I'll be available via PMs.   The next thing you will see from me is a nice video lighting 100 watt lightbulbs with no batteries    :)
« Last Edit: October 09, 2007, 07:25:59 PM by EMdevices »

dutchy1966

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Re: TPU - General Discussion
« Reply #202 on: October 09, 2007, 07:39:01 PM »
Hi everyone,

Just to support the direction we are investigating, here is a snippet of a tech document. No I don't have the whole document but it proves science is looking at it aswell....

Towards Modelling and Design of Magnetostrictive Electric Generators

During the last decades the interest in research and development of smart actuators, sensors and power generators  that used giant magnetostrictive materials is continually growing. Both academia and industry are actively looking for bread utilization of this technology for different applications (active vibration and noise control, structural health monitoring, self-powered electronic equipments and systems, MEMS, robotics, biomedical engineering, etc.). The proposed paper is in the field of applications of novel highly magnetostrictive materials for power harvesting, namely vibration-to-electric energy conversion. The term “power harvesting” is used for process of acquiring the energy surrounding a system and converting it into usable electrical energy. The problem of modelling and design of magnetostrictive electric generators (MEG) are considered. The fundamental basic for design of MEG is a Villari effect. That is, by applying a mechanical stress to a magnetostrictive material, the magnetization along the direction of the applied stress of the material varies due to the magnetostrictive effect. The flux variation obtained in the material induces an emf in a coil surrounding the material. The brief review on research and development of power generators using smart materials is given. Original MEG and the respective test rig which were built for study fundamentals of transduction processes of mechanical energy of vibrating structures into electrical energy are presented. Terfenol – D rod with 50 mm in length and 15 mm in diameter is used as an active material in MEG design. Test rigÂ’s measurement data have confirmed the expected performance of the MEG. These data are used for validation of the mathematical model of MEG that was developed and implemented in Matlab/Simulink environment.

regards

Robert

Grumpy

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Re: TPU - General Discussion
« Reply #203 on: October 09, 2007, 08:17:25 PM »

BEP

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Re: TPU - General Discussion
« Reply #204 on: October 09, 2007, 08:56:10 PM »
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« Last Edit: October 12, 2007, 03:51:50 AM by BEP »

bolt

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Re: TPU - General Discussion
« Reply #205 on: October 09, 2007, 09:15:28 PM »
EM do you think there are RF frequencies ie 500k + involved on the collectors or the collector is not placed into natural resonance but it is simply induced with magnetic harmonics of lower frequencies? This might work as a differencing amplifier and the gap between the collectors becomes the wave guide.

innovation_station

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Re: TPU - General Discussion
« Reply #206 on: October 10, 2007, 12:15:23 AM »
@ marco i know you have all you need
care to help me with tubes? i want to build a tube rack to test with but where to start?

hummmm...

how about the 12ax7 tube they are easy to get any guitar shop will have them

i want to build my amps as stable as possible and i want to use them on all rings the tube rack will be a peice of test equipment just like the scope it will be a nessary

tubes are the next step  ;D

and im all ready

@bolt is there  a certian tube you would reccomend? for this appclation?

shoping time ;D

but first we need a list!!

ist


Gothic

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Re: TPU - General Discussion
« Reply #208 on: October 10, 2007, 12:39:09 AM »
Also with the heating issues, you could use memory wire "nitinol" with a predefined shape imbed
  so when said unit begins to overheat the nitinol wire will deform overall design parameter and
  therefore degrade effeciency in effect a "thermometer"

http://en.wikipedia.org/wiki/Shape_memory_alloy

turbo

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Re: TPU - General Discussion
« Reply #209 on: October 10, 2007, 12:17:18 PM »
@ marco i know you have all you need
care to help me with tubes? i want to build a tube rack to test with but where to start?

hummmm...

ist

hey i'm also trying to build the tube drive from some old papers that i will combine.
maybe we can ask Pese about a 3 channel push pull circuit...

Marco