Tesla's "COIL FOR ELECTRO-MAGNETS".

[synchro1]

synchro01:

Speaking of Itsu's motor setup in his parallel resonant video, he had 4 magnets on the rotor and he used one generator coil. This meant that he got induction 4 times per one revolution of the rotor, right?  Now this means that checking the RPM of his rotor with a tachometer when the scope shows 150 Hz, the tachometer would display 9,000/4 = 2,250 RPM only and not 9,000 as you would think. For your diametric magnet case then the actual RPM would be 2 times 2,250 = 4,500! (at least as per following your logic of calculation for the diametric magnet case from Itsu's 4 magnet case when you say Itsu's RPM of 9,000 is equal to 18,000 RPM for the diametric magnet case)
This all means that your tachometer readings on the reflective tape attached to your spinner needs rechecking or you calculations needs checking?

It is okay that we all make mistakes,  however you again attributed to me a thing what Itsu did: it was Itsu who was raising his rotor speed to 206 Hz in his video, I just referred to it as the maximum speed occuring in his video, and I meant it to prove that your forever mentioned 18,000 RPM was not even approached in his video: still you wrote that he lowered the rotor speed to 18,000 RPM... lowered from what speed then??  (You wrote it in your Reply #691)

Gyula

Look, you're the one who is obviously confused if you're changing your mind now and maintaining that Itsu's running at 2250 RPM and quoting me as wrong, when you stated that his RPM was 9,000! Make up your mind!   



Here's the quote from you to refresh your memory:


"In his parallel resonance video, Itsu mentioned his gen coil has 27mH inductance and the tuning capacitor was 40uF, giving 150Hz resonance by the calculation. When he run the motor with the capacitor connected, the scope measured about 146Hz, now if you multiply this by 60, you get 8,760 RPM. If it had measured 150Hz ouput frequency from the generator coil still tuned by the 40uF, then the RPM would have been 9,000 indeed. And when he disconnected the 40uF capacitor, the rotor speeded up to a higher rpm, surely above 9,000 rpm".

[conradelektro]

I did some more measurements with the big bedini bifilar coil (see my post http://www.overunity.com/13460/teslas-coil-for-electro-magnets/msg383363/#msg383363, on the photo note the four turn exciter coil with white wire and the capacitors for LC circuit resonance tests).

Today all measurements succeeded (also with the wires separated or in parallel):

- self resonance, wires in series, air core 4600 Hz
- self resonance wires separated or in parallel, air core 58 KHz

- self resonance, wires in series, steel core 4000 Hz
- self resonance wires separated or in parallel, steel core 56 KHz

As MileHigh said, the self capacitance of the coil drops if only one wire is used or if the wires are used in parallel (from around 5 nF to around 600 pF).


The inductance of the coil with wires in series is about 4 times the inductance of the coil with only one wire or the wires in parallel.


The resonance frequency of the coil with only one wire or the wires in parallel in an LC circuit (with 10 µF, 1 µF and 0.22 µ F cap) is about 2 times the resonance frequency of the coil with the wires in series.


Last Thursday I must have had a bad evening because the measurements of the coil using only one wire or the wires in series did not work, but today everything went as it should. Measurements were done with a four turn exciter coil.

Attached is a PDF-file with all measurements of the coil if you are interested.

Tomorrow I will finish the "12 V DC motor magnet spinner" and then the "speed up under load" tests can begin.

Greetings, Conrad

[synchro1]

Here's a picture of Ed's rotor wheel and PMH; Apparently Ed made refrences in his book on Magnetricity to the use of the PMH as a driver coil for this 24 iron blade rotor:

[conradelektro]

I did the "pan cake coil on a steel plate and aluminium plate" test.

Both the bifilar and the monofilar pan cake coil show the same increase of inductance when put on a mild steel plate (34 µH increases to 50 µH).

Both coils do not show an increase of inductance when put on a aluminium plate.

As I recall, someone expected some magic when doing this test? Unfortunately there is no magic. But of course, I for sure did something wrong.

Greetings, Conrad

[MileHigh]

Conrad:

I hit the motherload for you and for other experimenters interested in measuring inductance and capacitance, and stuff like that.  You know how it is always wise to double-check your measurements when you do experiments, especially if you believe that you have out of the ordinary results.

I have only watched one clip from this gentleman so far.  I can tell you already that he is the real thing - the real real thing.  I can qualify people quite well and his first clip is amazing in its content and delivery and quality.  As far as his build quality goes and his use of his equipment goes, he is grade A-1 amazing.

The school of thought says one should go back to the basics and master them to give yourself a good foundation.  What did people do before they had inductance meters and capacitance meters and optical tachometers?  They used their scope.  In this clip he shows you two simple tests, one a capacitance measurement, and the other a very nice and clean variation on measuring inductance (or capacitance) using an LC resonator.  It's "cleaner" in the sense that you let the LC resonator resonate itself, and then measure the resonant frequency, as opposed to pumping a frequency into the LC circuit to measure its response.

http://www.youtube.com/watch?v=74fz9iwZ_sM

You notice that he has a special high-current-output driver.  It's a very nice touch but you can still do the tests without the special output driver.  Note however, how easy the driver would be to build using the same materials.

This guy is AMAZING and I am going to check out some of his other clips.  If they are as good as I suspect and the stuff he does is relevant or at least related to this discussion I will post a few more links.

MileHigh