The bistander thread

[Turion]

I think the two machines MAY have EXACTLY the same grade of magnets. The difference in flux is that on one machine the two 3/4" x 3/4" magnets are back to back with a thin layer of plastic between them (OLD machine) and the new machine has a 1/4"thick by 5/8" diameter magnet between them. In one machine the pull forces of the two magnets are added, but in the other machine the small magnet disrupts this. My problem is with the statement I found that says:
"As more magnets are stacked together, the strength will increase until the length of the stack is equal to the diameter. After this point, any further magnets added will provide a negligible increase in performance."

I'm not sure I agree with this completely. I remember testing exactly that at one point and seeing that I DID get some increase in magnetic attraction when I stacked some magnets. Not sure about their SIZE though. Will do some measuring tomorrow when I have time. What I DO know is my new meter shows a SIGNIFICANT difference in magnetic flux on the two machines. Enough to account for the difference in output. Although LOAD could affect output also. Lots of things that need testing.

[Turion]

Rethinking that iron strap test. I now doubt that will work out as I had thought. At TDC, all the cores (6) see a magnet of same polarity, so there is no flux return path via adjacent core. Return flux must use air and adjacent magnets.
bi

The coil on one side of the rotor sees a North magnet while the coil directly on the other side of the rotor from it (1 3/4” away) sees a South magnet.

[bistander]

You're not getting the point. He said adding more magnets once the "diameter was equal to the thickness or length gives you no additional strength". WRONG!!! Even with the piece of plastic as a GAP I got additional strength by adding more magnets. But my experiments show that the piece of plastic doesn't have much negative affect while the small magnet DOES. So the magnets on my new machine ARE DEFINITELY WEAKER than the ones on my old machine because of how they are put together. So I need to redo my rotor. And I will use 3/4 by 2" magnets for the increased pull strength.

I don't think think you've shown the magnets (themselves) are weaker, but that the configuration is less effective. I doubt that it is primarily due to the smaller diameter magnet sandwiched between the pair. Yes, that is a bottleneck in the flux path, but not much more than all the air path at the end of the core(s). I still think that proximy of nearby rotor magnets interfere causing flux to bypass portions of the coil.

Your project. But as long as you're in a test mode, those other voltage vs RPM plots would be helpful.

Your magnet on the iron plate flux test may be misleading because the large area of the plate presents a significantly different path than does a 3/4" core.
bi

[Turion]

I agree about the magnet on the plate! But better than getting fingers between two magnets. Been down that road far too many times. Will have time tomorrow for more testing.

[BroMikey]

I agree about the magnet on the plate! But better than getting fingers between two magnets. Been down that road far too many times. Will have time tomorrow for more testing.

[bistander]

Hello Turion,
are you there? Have you run any more tests? I would still like to draft those V vs f graphs and analyze. Or have you decided on a redesign?
bi

[Turion]

bi,
I haven’t done all the testing. Haven’t been able to pull the old machine out of the shop onto the back porch because of rain. And can’t run it in the shop now that my wife works from home because when you are in her office it is Extremely Loud and Incredibly Close. Not raining today but I am tied up. Will probably be able to get all testing done tomorrow. That is my plan anyway.

[Turion]

So I put a single coil in the new machine. At 1500 RPM I got 15 volts with the 100 watt bulb, just less than .4 amps
0 volts with the 200 watt bulb, just less than .4 amps
0 volts with the 300 watt bulb, just less than .4 amps
At 2,000 RPM the voltage went up about 2 volts on the 100 watt bulb and remained the same on the others
At 2,500 RPM it went up 2 more volts on the 100 watt bulb and remained the same on the others
At 3,000 RPM it went up 2 more volts on the 100 watt bulb and remained the same on the others

Tomorrow I will try with TWO coils. I will also run tests on the old machine tomorrow. I got an RPM meter all hooked up on it so I don't have to use that stupid inaccurate gun.

[BroMikey]

So I put a single coil in the new machine.

At 2,000 volts the voltage went up about 2 volts

At 2,500 volts it went up 2 more volts

At 3,000 volts it went up 2 more volts

Best get crackin cause the conference is just around the corner for the 3rd year in a row.

[Turion]

I will work on my projects at whatever speed I choose. I have a lot of irons in the fire working on different things with different people. This generator is the LEAST of my concerns. But I said I would finish it, and I intend to. I have more testing to do tomorrow, and a shop to clean up so I can work on some other stuff.

[BroMikey]

This generator is the LEAST of my concerns.

I have more testing to do tomorrow, and a shop to clean up so I can work on some other stuff.

Well at least you ran out of cement man work. Good luck on all yer irons

Free mag lock

[Turion]

bi,
Attached is a data sheet with my test results on the NEW machine. Apparently the coil I was using yesterday had a short in one of the wires, so that data wasn't worth anything. That makes me feel WAY better. BUT, I know that I have seen 97 volts output under load with this machine, so a top voltage of 72 volts at .7 amps isn't cutting it for me. Neither was the 97 volts, but this is WORSE. Anyway, this is for a coil PAIR directly across the rotor from each other.

Tomorrow I will run the same two coils on the old machine attached to the SAME meters as I used today. If the output is considerably better, I will probably pull the new machine apart and remove ALL the opposition magnets and then test it again to see if they are causing some kind of conflict. They are in a different placement on the NEW machine than they were on the old machine. The open voltage across the coil is over 100 volts different on the old machine.

RPM	Actual RPM	Load Watts	Voltage across Load	Amps	Open Voltage Across Coil
1000	1002	100	52.8	0.59	95
1000	1002	200	21.8	0.69	95
1000	1002	300	8.41	0.7	95
1500	1508	100	61.6	0.62	143
1500	1508	200	22.5	0.7	143
1500	1508	300	8.47	0.72	143
2000	2006	100	67.4	0.7	189
2000	2006	200	22.7	0.72	189
2000	2006	300	8.5	0.74	189
2500	2496	100	70.5	0.7	236
2500	2496	200	22.8	0.75	236
2500	2496	300	8.5	0.74	236
3000	2992	100	72.1	0.7	282
3000	2992	200	22.7	0.72	282
3000	2992	300	8.3	0.74	282

[bistander]

bi,
Attached is a data sheet with my test results on the NEW machine. Apparently the coil I was using yesterday had a short in one of the wires, so that data wasn't worth anything. That makes me feel WAY better. BUT, I know that I have seen 97 volts output under load with this machine, so a top voltage of 72 volts at .7 amps isn't cutting it for me. Neither was the 97 volts, but this is WORSE. Anyway, this is for a coil PAIR directly across the rotor from each other.

Tomorrow I will run the same two coils on the old machine attached to the SAME meters as I used today. If the output is considerably better, I will probably pull the new machine apart and remove ALL the opposition magnets and then test it again to see if they are causing some kind of conflict. They are in a different placement on the NEW machine than they were on the old machine. The open voltage across the coil is over 100 volts different on the old machine.
...

Cool!!!

Nice table. I'll dust off my laptop and plot this stuff.
Thanks.
bi

[BroMikey]

Cool!!!

Nice table. I'll dust off my laptop and plot this stuff.
Thanks.
bi

What did it look like?

[bistander]

bi,
Attached is a data sheet with my test results on the NEW machine.
...
Tomorrow I will run the same two coils on the old machine attached to the SAME meters as I used today.
...

Hi Turion,
Can you post the data from the test on the old machine?
Thanks.
bi