Self accelerating reed switch magnet spinner.

[MileHigh]

Conrad:

The two DC motors look fine.  I am assuming that these motors will increase in speed when you increase the voltage.  At the same time the available torque is quite high.  If this is true then my assumption is that in most cases the DC motor will run at a near-constant speed for most of your testing.  Perhaps only when the pick-up coil is very close will you have to slightly increase the voltage.

Note having a nice DC motor will be very handy and you will also be able to use it in all sorts of other projects.

I read your test protocol and it looks fine.  Naturally you are free to do just about anything you want but at the same time you have a "reference spinning magnetic rotor with a fixed (or variable) RPM" that can be used to make any type of A-B comparison testing of two or more coil configurations.  You can still try different distances or RPMs if you want.  With your variable DC power supply and a nice DC motor you can do just about anything you want. That sounds like fun!

- the output of the  "pick up coil under test" and the Wattage (Volt and Ampere -> Watt) necessary to drive the rotor with the defined rpm gives an indication of the "quality of the pick up coil" (its capability to generate electricity)

You are testing the ability of the pick-up coil to convert changing magnetic flux from a fixed-RPM spinning magnetic rotor into output electrical power.  You are much less concerned about the power consumption of the DC motor.  There are some subtleties worth considering so here is long discussion below about various issues:

I don't think that measuring the power consumption of the DC motor will give you that much information.  For starters, we know ahead of time that the power consumption of the DC motor will be much greater than the output power of whatever pick-up coil configuration that you test.  I must stress again that the idea is that the magnetic rotor will be spinning at a fixed RPM but the Lenz drag on the rotor can be variable.

That means that if you just look at the spinning magnetic rotor (and ignore the DC motor) then that is a fixed-RPM device with a variable mechanical output power.  The mechanical output power of the rotor will increase as you bring the pick-up coil closer to he rotor.  That means that the electrical power consumption of the DC motor will also increase.  However, it's very important to state that you cannot compare an increase in the measured electrical output power of the pick-up coil with the increase in input electrical power consumption of the DC motor.  The DC motor is an "unknown black box" and you don't know exactly what it is doing with the input electrical power to turn it into mechanical output power.  Therefore the "safe" measurement protocol is to treat the spinning magnetic rotor as a near-constant-RPM device.  You are aware that the mechanical output power of the DC motor is equal to the mechanical output power of the spinning magnetic rotor.  However, you cannot easily measure this mechanical output power in your testing.  Ultimately this is not an issue since you only want to compare the performance of different pick-up coil configurations.  Hence the idea of the spinning rotor as a "device that spins at a constant RPM under different pick-up coil loads."  That gives you a constant-RPM reference for testing the pick-up coils.  You "do not know" what the mechanical output power is but that's okay because you don't need to know it.

I put "do not know" for the mechanical output power of the spinning rotor in quotations because you can make inferences about it.  You can assume that the mechanical output power of the rotor is equal to the thermal power dissipation in the the pick-up coil assembly.  So that goes back to what I said before:  You know the resistance of the coil itself, you know the resistance of the load resistor, and you can measure the RMS current flowing through the circuit.  So the total electrical power measurement is equal to the total thermal power dissipated and that is also equal to the average mechanical power being provided by the spinning rotor.  You also know the RPM (or angular velocity) of the rotor.  Therefor you have all of the data necessary to calculate the average torque being supplied by the DC motor to make the magnetic rotor spin.  It's interesting to note that you can't directly measure the average torque of the spinning rotor, but you can measure it with quite a bit of accuracy (probably within 1%) by simply number crunching the RMS voltage measurement from your scope display!

MileHigh

[MileHigh]

Synchro1:

Here is Igor's second clip again:

http://www.youtube.com/watch?v=mzNjAs3-9LA

Look at the left digits on the power supply showing the current draw of the setup.   When Igor inserts the ferrite rod into the core of the coil tell us if you see the current increase.   When he removes the rod tell us if you see the current decrease.

Note also that he is most likely crippling the usefulness of the ferrite rod by attaching the magnets to it.  Chances are the LEDs would have gotten much brighter if he inserted the ferrite rod alone without the attached magnets.  Notice however that he never makes that test, he failed to do an A-B comparison of rod with magnets vs. rod without magnets.  Naturally without making that test there is a possibility that you could lead yourself down a garden path and make incorrect conclusions and inferences.  The more information you have to work with the better off you are and the better your understanding of your test setup.

MileHigh

[Magluvin]

Specially for synchro1, some facts about Reed switches. Switching frequencies above 20 Hz will produce unexpected results. Switch time is around 50 ms.

Driving a magnet spinner with a reed switch will be problematic above 1200 rpm (20 Hz).

http://www.meder.com/fileadmin/meder/pdf/en/Technical_Documents/Parameters_of_Reed_Switch.pdf

It is not forbidden to try higher frequency switching with a Reed switch, but the results will be unpredictable. But there could be a conspiracy about 400 Hz switching with a Reed switch (24000 rpm), watch out.

Greetings, Conrad

Funny thing about reed switches. They have resonant freq also. So I would bet that the max recommended switching speeds are below any resonant freq known to the reed.  But if you find these res freq, may vary even in the same batch, then you could build the circuit around that and use the reed at its natural freq of movement.   

There are more than one freq the reed will show its colors. Below is a vid of mine that shows my  motor breaking through these areas between resonating reed freq. The coils are .45ohm not .9 ohm as stated in the vid.

http://www.youtube.com/watch?v=B7QIpfSX_4Q

So the reeds can be used at higher freq than recommended, just not all the frequencies above recommended. And Im sure there are absolute limits. These big reeds cannot compete with tiny ones when it comes to speed.

Mags

[conradelektro]

Folks, take a look at this quote from Conradelektro from earlier in the thread:

"I am interested in this type of coil because I could feel this "rattle" in my fingers (which means "some strong force"), but the rotor did not slow down (the tub magnet has to be at a certain distance from the spinning magnet). That is interestingly strange. Maybe this "vibrating magnetic field" induces more current into the bifilar winding than one would expect. We will see, thank you for disclosing your observations I will try to replicate".

Ask yourselves what Conradelektro did wrong to get the failed results he posted? Practically everything I told him not to! Now he's dropped the "Synchro Coil" project cold!

I had no prior experience holding something that is attracted to a magnet (a piece of iron, another magnet, a coil with an iron core, a coil with a magnet stack core)  near a spinning magnet with my fingers. And if you do that you feel this "rattle" or "vibration". And this rattle and vibration increases and diminishes with the distance from the spinning magnet. And there is a certain distance where the effect is very fine (but you still feel it) and the rotor seems to stay at a stable speed. This happens because your fingers are very sensitive and the rotor speed change is not visible without very good instruments.

This "rattle" or "vibration" occurs because the spinning magnet offers a cyclical changing magnetic field to the "thing" (if it is attracted by the spinning magnet). This is also the reason why a pick up coil picks up a sine wave current and not DC.

So, I was fooled by sychro1's outrageous claims, by my inexperience and by my eagerness to detect something strange. But I am only fooled once by the same fool.

So, I made an error of judgment. But I learn from my errors.

And when building and testing my "synchro coil replication" I did everything as I understood from synchro1, no intentional falsification. And I will do his beloved "one layer synchro coil test" when I find the time. But there is no hurry. I am not a full time experimenter. It is just a hobby and I do experiments only every now and then. And I do things that I find interesting (for whatever reasons). I do not take orders from others. But I like suggestions, clarifications and corrections from others (as long as they have some real experience), because I want to learn. And believe me, I would very much like to see something extraordinary. But that is more difficult than expected. In this respect I was really naïve.

Synchro1, may be you can be less aggressive, less vindictive and less misguided by wrong concepts in 2014? Nobody is sabotaging anything or anybody. Nobody is in a conspiracy against you. Calm down, stay cool, and have a happy new year.

Greetings, Conrad

[conradelektro]

Also, I think it may be tuff to make a pancake bifi that will operate in the motors freq range. Were probably talking huge diameter even with fine wire. Tesla said the bifi config can be applied to any style of coils.

Mags

@Mags: May be it is sufficient to wind a bifilar pancake coil which rings at a higher harmonic to the rotor frequency?

Example:

- bifilar pan cake coil rings at 12.800 Hz (50 * 256)

- rotor spins at 3000 rpm = 50 Hz (I see the 1 AC cycle for each revolution of the "diametrically magnetized spinning magnet" in my measurements)

The idea is to measure the ring frequency of the bifilar pan cake coil (with my function generator) and then to adjust the rotor speed to a lower harmonic (by varying the supply Voltage to the 12 V DC motor which I plan to use in the future to spin the magnet).

Greetings, Conrad