The littel test alt is underway.

[Jerry]

The other diary was getting abit to long. So I thought I would just show this littel test project as it progreses so folks could tag along.

It will do 2 things. My grand daughter is helping me with it. So she can diplay it at her school science fair. It will light up a few LEDs for her at school. It should do that with very littel rpm.

The school fair is in late march so if we hurry and get it together I'll use it for my delta, jerry riged, my star and Flux if you can addvize the size of wire to use in this one to make thew compairison for normal star. I'd like to use one wire only cause this thing is very tinny. 2 in hand would be hard to wind on this one. The discs are 4 and 3/16" diameter.

I've wound the first delta-jerry riged coil. The magnets are 1"X1/2"X1/8" NEOs.

A made littel 1/4" plexi pieces to wind the coils on. They are the same shape and size as the magnets (just a pinch longer).

The coil is 200 turns of 24 gage. For the next star I hope to wind 100 turns of 21 ga. This is half the cercular mills of the 24 gage. I'm doing this because as stated it will be real hard to wind 2 in hand with a coil that is only 1/4" thick.

And Flux if you can sugjest the proper star gage and count I'll do my best to make those coils. I will make 3 removeable and interchangable stators.

OH I've got some pix of this so far but I've yet to load them I'll do that now.

                     JK TAS Jerry

X

[Jerry]

This is a 4 magnet 3 coil 3 phase pma. To make it quike and easy I've simple cut three 2" inch holes in a 6" diameter X 1/4" thick plexi disc. The coils will lay in the holes in proper alignment . There will be a 6" diameter disc 1/16" thick glude to iether side to holt the coil inplace. 1 cap first then coils then some reson then the other cap the skwish and set.

Heres the pix of the littel plexi coil ceneter pice. I've cut 10 of the littel pieces and I'm just leaving in the center and gluing them inplace with the coils.

 

Here is the coil winder.

Here is the plexi stator form with coil inplace.

Here is the stator for the coil and one of the 2 lids(1 top 1 bottom).

Thats all for now.

                          JK TAS Jerry

[electrondady1]

two birds one stone jerry, slick.

[Flux]

Jerry

Star 116 turns. I am not familiar with your wire sizes, but converting to metric and back it seems to be between #21 and #22. Looks like a half gage.

Perhaps Zubbly can confirm this.

Flux

[zubbly]

Flux and jerry.

forgive me but i have sort of lost the original intent after all the debate that has gone on.

i "think" you plan to use a stator designed that can be connected either delta or jerry rigged and wanting cut in at a specific rpm. i then "think" you intend to make another stator designed for star conection and to give you the same rpm cutin as the delta/jerryrigged. if this is correct, please give me the winding data for either of the stators and i shall give you the proper turns and wire size for the other.

flux, i hope this is what you are asking. if i am wrong, could you explain just what you want a litle more.

zubbly

[Jerry]

Hi Zubbly.

I'm building a small test dual rotor alt as discribed above. This alt will have 3 changable stators. One stator has 200 turns of 24 ga wire (delta/jerry riged). As per my wire gage ? from a couple days ago, as you and others stated 21 gage is twice the circular mills of 24 ga.

I'm hoping that 100 turns per coil will fit stator #2(star). Flux has sugjested stator #3 should have 116 turns of a wire gage that apears to be between 22ga and 21ga. This is a half size or a metric size? Thats the question. Stator #3s 116 turns is to compesate the normal star stator for its 1.73 X delta diferance.

I think I'll use the 22 ga. for stator #3 cause thats what I have and if 21 ga will make 100 turns in the space I have 22 ga. should make the 116 turns Flux has requested.

                   JK TAS Jerry

[Flux]

Zubbly

Jerry wants a direct comparison between star and delta. He has 200 turns of #24 in delta so he needs 116 turns of a wire with 1.73 times the csa (circular mils I believe you call it) and wants it in a single wire.

We have a limited choice of wires here but it could be done near enough with a choice of a non standard size.

I have no idea what choice of wire you have over there, in the days before we went metric there were theoretically about 4 sizes between each SWG size but rarely could you get most of them. I suspect it was a way of using up wire that was off nominal size when the dies were worn.

Flux

[zubbly]

hi jerry!

Flux is correct on the 116 turns for a direct change from delta to star.

#24 gauge wire has 404 circularmills (the delta winding)

so, 404x1.73=698.92 circular mills for the star winding

#22 gauge wire=640 circular mills

#21.5 gauge wire=724 circular mills

#21 gauge wire=812 circular mills

#21.5 wire would be the closest you can get to what is properly needed. if loading is not really a concern, then #22 can be used.  the difference between #21.5 and #22 is 64 circular mills. 64 circular mills is a #32 gauge wire which is .008 inch diam.  not much thicker than a thick human hair.

hope this helps!

zubbly

[spinner]

jerry

a quick note of thanks for your efforts and detirmination...i find if I read thru a thread eneough times *lol even I get something out of it!

thanx

spinner

[Jerry]

Hi Flux.

I just wound a 100 turn coil of the 21 gage and it fits the hole prety tight but I think I can squeez it in there? All I have is 22 gage for the normal star 116 turn coil I think it will fit no problem. I gues if the holes are a littel tight I could open them up slightly with my dremel.

                        JK TAS Jerry

[Jerry]

Thanks Zubbly.

22gage is what I have and I think as you've discribed its close enough for this test.

                           JK TAS Jerry

[Jerry]

Hi Spinner.

This debate seems to be endless. So I'm hopeing my littel test alt with the 3 diferant stators will help shed some light on the subject and be easyer to follow.

The acctual diferances should be quite aperant.

                          JK TAS Jerry

[Jerry]

Just did a dc measurement on the 21 gage coils. Accounting for the test leads .05 ohms

The coils (116 turns of 21 gage) measure .56 ohms. This would then give 1.12 ohms between any 2 star legs.

The delta coils (200 turns of 24 gage) measured 1.81 each.   This will then equal .603333 ohms for delta/jerry riged.

                     JK TAS Jerry

[oztules]

well on those figures, jerryrig should outperform star all the way up the chart. Both into the same load. the graph should only converge at zero, and jerryrig should pull away indefinately as the current rises (and thats with the built  in star cheat extra turns).

[Jerry]

Yep exactly. thats what I"ve been saying. For the same amount of copper and magnet material and all other physical charictoristics being the same to me it apears delta/jerry riged should have better output.

However the jury is still out and I may be totaly wrong?

2 stators are done. The 200 turn delta/jerry riged and the 116 turn star cheat extra turns. A littel more copper by volume and weight then the delta/jerry riged.

In therory these 2 stators should produce the same voltage.

So normaly if delta volts are 10 then star volts should be 17.3.

To make delta be 20 volts I wound it with twice the turns of wire half the gage of star.

to make star have 20 volts I gave it 16 more turns to help it catch up with delta (20 volts) voltage.

So now in therory then these 2 stators should have the same voltage.

The magnets are glueing on the discs so I may do assembly tommorow.

                    JK TAS Jerry

[oztules]

at low curret that should be the case, but if Peter ( the netherlands) is correct, and delta is 1/3 single coil internal resistance, and flux is correct (same efficiencies but for circulating currents and jerry rig substantially overcomes this), then one would have to expect that as current rises in both systems, jerryrig will pull ahead as more power is dissapated in the star config, than the delta.

This one would expect would lead to blade stall. But looking at one of Hughs comments to Danb yesterday, it may well be that judicious use of resistance in the line could help ameliarate this problem.

So I guess the answer may lay in a variable resistance in the line to the load. ideally this will vary as the current increases. ie no resistance at low current, and higher resistance as the current tries to stall the blades.

luckily, heat alters the resistance of metals quite nicely, so maybe a heap of headlights in parallel with each other but in series with the load, will serve as a dynamic load varying device.  When current is not sufficient to create a decent voltage drop in the filamants r= very low (dependant on how many you have in parallel i guess)

As  current rises, so voltage drop over small resistance increases. The power dropped watts= voltage dropped squared resistance of filaments. So effectively, as power is dropped over the resistance, heating will occur. As the heating occurs, filaments heat up with power dropped as a square of the voltage drop. As this is going on, filament temperature increases will increase the resistance. The balancing act is to find how many head lights will give you the control for any given system. This may add softness into the system, and allow the collection of heat in places other than in the stator coils, and be one way to tune the system, and get something back, instead of opening the gap and losing the advantage of big magnets, and low resistance windings. It is also a low tech way of getting some current regulation in the system.

if not headlights, then heater filament windings or some other resistance temperature device.  we are looking for a dynamic resistance not a fixed one.

This could then produce a higher impedance input for the gennie, helping to lower its coil losses, and move those losses to an external device (the headlights). It would also allow the blades to produce their power staying closer to tsr where their power is max.

This kind of thing may allow your lower resistance higher power /rpm device to not stall the blades, and perhaps wind the coils for lower cutin speeds.

...............oztules