New positive proof of a working Newman fan motor charging a battery

[CLaNZeR]

I have just managed to source a reel of 0.25mm(34SWG) x 3.2KG wire

I think I am going to build a winding machine using stepper motors as I think this will save alot of time and it can be used for other projects I have been planning on doing anyway.

I will use 1 stepper to Rotate the coil I am winding and another to move the wire feed arm along.(Basically a 2 Axis CNC bodge LOL)

What I am stuck on is how to keep the wire Tension correct, anyone know of a cheap method of tensioning the small wire as it gets wound?

Regards

Sean.

[hartiberlin]

Hi Dom,
if you put a bulb or a 1 to 10 Ohm shunt resistor  in series with the battery minus pole and put a scope across it,
try to see, if you also can get these big back current spikes into the battery as is shown
here:









You probably have to tune the sparking contact to
get the right spark and then these back current pulses
will apear, when the coil is sitched off.

[pg46]

Hi All-

Got 2 -  3.25" ring magnets from speakers. Used a 4.5" piece of PVC pipe to house the motor. Spent hours wrapping coil wire around it!  Did the figure 8 type of wind that mrd10 suggested. Hooked it up to a slightly depleted 12 V battery.
Draws less than 50 millamps now at 12 V so that's good. Rotates fairly slowly- think thats OK. I will leave it on awhile now and see what happens to the charge. I can see though that I will have to fix the sparking arrangement by trying different materials and configurations etc. because the spark seems kind of weak.( I am using copper to aluminum just now) So not sure that this arrangement will charge the battery any but we will see.
Wanted to mention though that a few times while adjusting the leads off of the battery that I got a fair jolt as in a bit of a 'shock' so I am optomistic that it is kicking out big voltage spikes. You can't get that kind of reaction off of just 12 VDC.

Will Post any new results later on.

[hartiberlin]

@PG46,
check out your electrical ON-Off firing position versus magnet position
inside the coil.
If you change this angle you can optimize for faster speed
or lower speed.
At different angles you will have lower speed and more BackEMF.
If you want faster speed you will get less BackEMF voltage,
so either you run this thing as a motor or as a generator of BackEMF
to recharge the batteries.
It is all in the tuning of the sparking
commutator and the angle magnet versus firing setup.

[pg46]

hartiberlin-

Thanks for the tips. Yes, I see what you mean regarding the speed. I don't want a motor after all so I think I will aim for the low revs and big sparks!
I wonder how large these machines have to be to be of practical use? I wonder too if they can harm batteries by overcharging? Nice problem to have mind you.