Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated

[listener191]

The first scope shot shows the coil current including the low side switch period.

So just 5 coils switching no overlap.

The second shot shows the board supply current.
Note the low side switch is on another board so you don't see that current.
No sign of any recovery current to the cap bank.
Perhaps the local cap on the board is taking this charge, so it does not appear on the supply rail?

I disconnected the loop and it made no difference, so I was wrong about that.

Regards

L192

[TinselKoala]

Luc, we have mentioned before that the maximum rated continuous current output of the Mega is 200 mA total. You definitely should be using a current-limiting resistor in series with _each_ LED to limit the current to something like 5 mA per LED. With modern bright LEDs this will be plenty bright for visual display purposes. Even though you aren't turning on all your LEDs at once, you still need some current limiting for the LEDs. For a Green LED with a Vf of say 1.8 V, and the 5 V supply, you need to calculate the resistor value like this: R=V/I so R =(Vsupply - Vf)/5 mA = (5-1. 8) /0.005 = 640 ohms. So use a resistor value close to this for each LED. (I'm using 470 ohms on my test board.) This way even if all 30 LEDs are on the system will draw 150 mA, well below the total limit. (The speed control pot will draw a little current also but if you use a reasonable sized pot this will be negligible.)

It is possible that your uploading and intermittent problems have to do with the high current draw. (At fast speeds it "looks like" all LEDs are on at once, causing the thermal overload problem.) This is why I suggested earlier that you try the uploading with all external circuitry disconnected from the Mega. If this solves your uploading problem then you will know the cause, and can most probably cure it with adding current-limiting resistors to all your LEDs.

Driving a mosfet, as has been pointed out before, doesn't need much current usually. So you should be able to drive the LED+resistor, and the mosfet, for each of the 30 switches with no additional problem, once the LED current is limited.

There is no need to switch to the Propeller system. It will have similar output current restrictions, and it uses a different IDE interface and IIRC it uses a variant of the BASIC programming language. While any program can be written in just about any language.... I think you will have more help available if you stick to the Arduino system and the C++ language. If it turns out that you have a defective Mega we can arrange for you to get a new one. If it turns out that you need more current than the raw Arduino can supply you can always put in current-amplification transistors between the Arduino outputs and the mosfets (or H bridges or relays, whatever).

But FIRST THINGS FIRST, try uploading to the Mega with _all external circuitry disconnected_ to see if the current draw is really the problem.
If it works fine this way, then you can probably cure the present problem simply by adding the current-limiting resistors to each LED.

[T-1000]

Looks like I have a problem.  I spaced my coils 6 slot wide and I'm having terrible results.  PmgR said it shouldn't matter but maybe it does?...  I need opinions as something is not right.

See results: https://youtu.be/aFQB-WOx-Oc

Hi Luc,

I am finding your coils aligment do not match Pierre's winding style.
Your setup have 2 coils in single slot while Pierre made just 1. Please see video screenshot attached.

The second very important thing to remember - the magnetic field strentgh weakens to the distance from coils squared. Which means in your setup you need to put out really strong magnetic field on stator to reach coil in the middle. Which also means the bare minimum power required will be high to induce current on the output. This is where bank of supercaps may play crucial role.

The third thing, when you attach 12V battery I suspect internal Arduino 5V stabilizer is messing up or is partially burned out. You may diagnose its issues or make external circuit to cope with power consumption on LEDs/etc. Personally I would introduce mosfet drivers to output transistors when driving coils.

Cheers!

[listener191]

Hi Luc,

I am finding your coils aligment do not match Pierre's winding style.
Your setup have 2 coils in single slot while Pierre made just 1. Please see video screenshot attached.

The second very important thing to remember - the magnetic field strentgh weakens to the distance from coils squared. Which means in your setup you need to put out really strong magnetic field on stator to reach coil in the middle. Which also means the bare minimum power required will be high to induce current on the output. This is where bank of supercaps may play crucial role.

The third thing, when you attach 12V battery I suspect internal Arduino 5V stabilizer is messing up or is partially burned out. You may diagnose its issues or make external circuit to cope with power consumption on LEDs/etc. Personally I would introduce mosfet drivers to output transistors when driving coils.

Cheers!

Re post 410 in the other thread.
These were the numbers that Pierre provided.

1-6,2-7,3-8,4-9,5-10,6-11,7-12,8-13,9-14,10-15,11-16, 12-17,13-18,14-19,15-20,16-21,17-22,18-23,19-24,20-25,21-26,22-27,23-28,24- 29,25-30,26-31,27-32,28-33,29-34,30-35,31-36,32-1,33-2,34-3,35-4,36-5

There are two coils in each slot.
Pierre's windings are very tight so you don't  see the second coil entries behind the first.

L192

[T-1000]

Pierre's windings are very tight so you don't  see the second coil entries behind the first.

L192

Which is critical point in regards to magnetic field polarity. The closest to the center you see are just 1 way wiring making 1 magnet pole. The other coils looking to the outside of the stator make second pole.
So it is like magnet N/S looking towards center. When 2 coils are activated at once that makes N+N/S+S magnetic aligment towards center. A bit of tease for this case - the aligment of magnets in E. Leedskalnin generator in Coral castle - http://www.leedskalnin.com/LeedskalninImageArchive.html .

P.S> 1 slot I ment are 1 slot looking towards center and 1 slot looking towards outside of the stator.

Cheers!