How to install and tie together magnet wire coils

[aidrenegade]

Hmmm..... I'm thinking a conversion to DC output may be on the cards. My build quality means knocking sounds and too much vibration over about 500rpm. With the coils connected as above I still get the same result of about 3.3v at 270rpm. I tied 2 180 degree opposite coils inner to inner wire and got 39v ac at about 620rpm. Inner to outer wire was not worth the effort.

I will have to look more into converting to dc and possibly aiming for 12v and buy a cheap inverter. For ac I think 12 pairs of magnets but only 10 coils is probably causing problems.

[aidrenegade]

So OK, after much wailing, knashing of teeth, swearing and possibly breathing in to much supa glue fumes I think I've managed to convert my magnet arrangement to all magnets set NS, NS, NS, etc to produce a dc current. I noted previously that 12v ac needed about 370rpm to produce. I'm leaving the magnets alone till tomorrow morning to (hopefully) ensure all the supa glue has dried so I can remove the spacers (see photo)

So now I'm into new dc experimtation. I've also brought a 700w, 12v dc / 230vac inverter. 240v output would have been better but I brought the best I could afford. This should'nt be a problem as I'm using a 400w rated dimmer switch to control power to the drive motor. Bearing in mind I'm not using any kind of 12v battery, and allowing for a bit of 'load', any ideas on what voltage I should feed to the 700w inverter? Of course as yet I have no idea what amps my 10 coils of 370 turns 0.71 enameled wire will produce at a 12v dc output.

For anyone across the pond I think .71 wire equals about 22 gauge wire as per this conversion chart:
http://www.calculatoredge.com/charts/msteelsheets.htm

Can I measure the amps output at 12 v dc using my multimeter if there is no load on the coils? I'm sure this is 'schoolboy' stuff for many of you but I left school in '84 and most of this info is forgotten! Any help / ideas on how to test and see what I'm generating with a multi-meter would be helpfull!

[gyulasun]

Hi aidrenegade,

You still have 12 magnet pairs and 10 coil so you probably will not have DC output voltage directly from the coils and you may have to use rectifiers to get suitable DC voltage to feed the inverter.  If this proves to be correct, then the links shown above to use a full wave rectifier with 2 diodes per coil only instead of a 4 diode bridge is still a good option (you can save half of the total diode loss). If this happens to be needed,  the link above to such a rectifier is okay albeit it is a voltage doubler, you can control output voltage by the rpm control to your prime mover motor with the dimmer for sure.  So I suggest paralleling all the coil outputs via the rectifiers into a common DC output.

Let's do some simple calculations. Your prime mover's motor power is rated as 120W, right? Let's remain in this power range, while it is okay that your inverter is rated to give out 700W.  This latter means that at its 230V AC output it would be able to drive a load which draws about 700W/230V=3 Amper, ok?
At the inverter's input side this power would "translate" as follows: the inverter has its own efficiency which is load dependent too but let's say it has 90% efficiency at the 700W power level so at the input side you have to feed in 700W x 1.1  i.e. 770W. This would mean that at the 12V DC input level the DC current load towards you generator output would be 770W/12V=64.1 Amper!  This is why I wrote above let's remain in the 100W power range instead of 700W, first of all due to your prime mover's power capability even if you consider your setup to be something extraordinary, right?
So in case you would load the 230V AC ouput of the inverter with a normal 100W 240V incandescent lamp, the input current demand at the 12V DC input would be about close to (100W*1.2)/12V=10 Amper (I considered only 80% efficiency in this case because inverters behave like that). This 10A current will demand about 1A current from each coil if you parallel all the coils via the diode rectifiers and store the total output energy in the capacitors.  This now could be fulfilled by your setup when you use the 120W rated prime mover and a 100W load at the inverter AC ouput.
I know that this is a conservative and conventional approach but first I suggest to keep near to this power level for the first tests to see what your setup is capable of.

Regarding your question on "the amps output" at 12V DC:  This is an impossible question, sorry to say so. Your coils behave exactly like generator coils would do so if you do not use a load, then no sense to measure the short circuit current,  for an ampmeter does represent a practical short circuit across your output coils, should you connect one across a coil, ok?
The optimal case for a correct load instead of a short would be an impedance matched load at your generator coils output, this considers the DC wire resistance of the coils and their AC impedance at the given rpm. Just look for how to get maximum output power from a generator. 
A good start here would be to use an Ohmmeter and measure the DC resistance of each coil (well they will be probably identical), this DC resistance will probably rule in the impedance because the inductance of your coils at the rpm range used may be less.
I suggest using the rectifier referred to above at a single coil output first (obtain at least 10A 40V Schottky diodes, from computer power supplies etc) and load the DC output with power resistors (but 12V car headlight bulbs may be used, remebering they are nonlinear), you may wish to use a DC voltmeter in parallel with the resistor or the lamp load and a separate DC ammeter in series with the resistor or lamp load. For the two electrolytic capacitors shown in the link, I suggest at least 10000uF or higher, with 25V or rather 35V DC ratings.  OF course you know now that to load a single coil output with 1 Amper current the power resistor should be about 12V/1A=12 Ohm IF you adjust an rpm to have 12V DC across the capacitors when this 12 Ohm is connected.  The heat dissipation in the resistor would then be 12Watt.  Use car lamps accordingly and as per you wish to load the total output.

rgds,  Gyula

[aidrenegade]

Hmmm..... Dam it! I didn't see that one coming! With all magnets set NS, NS, NS etc the north poles are all facing inward, magnetizing the steel axle and over powering the levitation magnets and pulling the whole assembly down onto the coils. I guess first I need to try turning all the levitation magnets through 180 degrees to make them south pole to south pole and see if it makes any difference. If not I guess I need to make a non ferrous axle out of something.

[aidrenegade]

Good news / bad news. Good news is that flipping the levitation magnets worked but it still puts out an ac voltage so it's time to look at the other suggestions made above. Note to self! Next build factor in the same number of coils as pairs of magnets.