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Kamak
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Joined: 13/04/2021
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Posted: 04:25pm 20 Apr 2021

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Well maybe that's a reasonable assumption, but it's an expensive one. 3-phase high voltage 50A primary to low voltage secondary transformers are damn expensive.

Kamak
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Location: Canada
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Posted: 04:33pm 20 Apr 2021

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Butcher said I have a 36 pole F&P (factory de-cogged) stator that had Alluminium wire on it. I unwound the al wire and placed into my scrap bin. I am winding 0.8mm Copper wire onto it (same number of turns).

I estimate that it will take me about 9 1/2 hours to do so! I have done about 10 poles already. It takes me about 15 mins per pole on average (sigh).

Point is, you may want to stick with Alluminium!

Soldering to Alluminium is difficult and it can be unreliable etc.

You could simply unwind one pole and count no. of turns and then rewind...

Be careful. Anything over 50V can be lethal. I am not joking. I am talking 50V peak to peak, not RMS either.

Thicker wire = more voltage due to less ohmic losses (less resistance) thus greater efficiency.

So, how uniformly made are the windings that you managed to rewire?
How come you didn't want to increase the number of windings per pole?
How much do the windings (@ 0.8mm dia) protrude above the poles? Is it the same as the aluminum was? What was the dia of the Al wire again? 1mm? 0.9mm?

Kamak
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Location: Canada
Posts: 150

Posted: 12:29am 21 Apr 2021

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A new method of steady-state measurable RPM.

Kamak
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Posted: 12:32am 21 Apr 2021

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185hz = 462.5 rpm
185/24 pole pairs x 60sec. = 462.5rpm

Kamak
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Joined: 13/04/2021
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Posted: 12:32am 21 Apr 2021

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The stock voltage Vp output of one phase at 462.5rpm.

Kamak
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Posted: 12:33am 21 Apr 2021

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Crimped on a common point connection.

Edited 2021-04-21 10:33 by Kamak

Technophiliac

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Joined: 18/12/2020
Location: New Zealand
Posts: 92

Posted: 01:49am 21 Apr 2021

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What's the voltage drop to with a load on e.g. - PTC heating element or ceramic dump resister - or?

Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two.

Kamak
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Posted: 02:12am 21 Apr 2021

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Technophiliac said What's the voltage drop to with a load on e.g. - PTC heating element or ceramic dump resister - or?

I haven't gotten that far yet. I'm still waiting for the 50A/1200V 3PH rectifier to show up. And I'm trying to figure out what size dump resistor to buy. Probably a 750 - 800W unit? But what ohms?

I'm thinking about running this thing at 200V approx. What are your thoughts?

Technophiliac

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Posted: 02:49am 21 Apr 2021

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Brief reply - Remember a dump load resister does not need rectification to use - but if 3 phase AC then 3 symmetric dump loads might be usefully used. One might say this is complex, plainly you are not troubled with complex. Would need someone more clever than me to speculate the voltage under load, suffice to say I expect it to be lower, and may be surprisingly low - if my generators are anything to go by. I also observe generators have a rating, typically the Chinese rate their turbines at wind of 11 m/s or so(!) My point is a generator is better rated and understood with its power curves in a specific scenario.... taking into account particularly speed / torque and load. If it were me I would just hook up some sensible loads and measure what happens to get a scoping of what we have.... I am not saying my approach would be better, its realistically described as the quick and dirty approach, nothing more.

Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two.

Kamak
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Joined: 13/04/2021
Location: Canada
Posts: 150

Posted: 03:11am 21 Apr 2021

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Well, I thought you would put a dump load resistor after the rectifier. This was just a pure guess on my part. I really have no idea. I'm still learning as I go here.

I don't really want to hook up three loads to three phases. So I was going to load it after I got the rectifier (soon I hope)

Any reply is greatly appreciated, so thanks for anything you can add. I know it's kind of quiet over here in the wind turbine threads now. lol
Edited 2021-04-21 13:13 by Kamak

Kamak
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Posted: 05:29am 21 Apr 2021

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Selecting Wire Size for a 50A Star wound 3PH Generator

Using a good rule of thumb of 300-400 CMA (I'll use 400) per Amp

Approx 16A per single star leg?

16 x 400 = 6400CMA

from the chart, 6400CMA is close to a 12gauge single strand wire with 6500CMA.

Edited 2021-04-22 06:12 by Kamak

Kamak
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Posted: 08:38pm 21 Apr 2021

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confirmation of RPM through two methods of measurement. Digital tachometer and electrical AC frequency.

Approximations due to fluctuating loads.

Tachometer reading of 205/209.6 RPM
A voltage reading of 55.5V DC
A frequency reading of 85.4Hz
85.4 Hz(cps)/24 N|Spc x 60 spm = 213.5 rpm
cps(cycles per sec), N|Spc (pole pairs per cycle), spm (sec per minute)

Edited 2021-04-22 06:39 by Kamak

Kamak
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Posted: 09:40pm 21 Apr 2021

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It was a small short 4s (8MB) gif file, but it doesn't upload as a gif.

Edited 2021-04-22 07:44 by Kamak

Kamak
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Posted: 07:45pm 22 Apr 2021

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Better Test Bed

Edited 2021-04-23 05:47 by Kamak

Kamak
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Joined: 13/04/2021
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Posted: 01:08am 23 Apr 2021

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Stock rotor/stator: (10ohm loads(100W incandescent bulbs), 120V, 0.919A)x2, 500 rpm, 110W(x2),Single phase ea @ 220W total. I could put another bulb on leg 3, I just didn't have one. So 330W @500rpm could be done.
Obviously, I need to increase the magnetic flux density. This needs to be 800W at 200rpm.

I have a 2 ohm, 750W resistor coming, and the 3 phase rectifier. Waiting, waiting, waiting...

Edited 2021-04-23 11:21 by Kamak

Technophiliac

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Joined: 18/12/2020
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Posted: 01:39am 23 Apr 2021

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Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two.

Kamak
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Joined: 13/04/2021
Location: Canada
Posts: 150

Posted: 02:12pm 23 Apr 2021

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Selecting Wire Size for a 50A Star wound 3PH Generator (even if it could achieve this) @ 24V @1200W

Using a good rule of thumb of 300-400 CMA (I'll use 400) per Amp

Approx 16A per single star leg? 50/3 = 16.66

16.66 x 400 = 6664CMA

from the chart, 6664CMA is close to a 12gauge single strand wire with 6500CMA.

But....

50A Star wound 3PH Generator @1200W (even if it could achieve this) @ 48V @1200W
That would be 25A

For a (3x4C)3, that's 9 parallel legs @ approx. 2.3A per leg.

2.3 x 400 = 920CMA

from the chart, 920CMA is close to 20 gauge (0.03196inch 0.8118mm) single strand wire with 1024CMA.

But if I select for the worst-case scenario, with 1200W @12V that would be 100A

For a (3x4C)3, that's 9 parallel legs @ approx. 11.11A per leg.

11.11 x 400 = 4400CMA

from the chart, 6530CMA is the nearest single strand wire to 4400CMA which is 12gauge (0.08081inch 2.053mm).

That's much higher than 4400CMA, but it's the nearest. standard gauge single strand size "above" the CMA requirement. There would be no worries about voltage drop or heating using it for 12V service.

(3x4C)3 @48V is approx 150 RPM (from the F&P chart)? Unknown for a Samsung BLDC Generator with changed-out magnets and rewired with the proper gauge copper wire.

Edited 2021-04-24 00:54 by Kamak

Kamak
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Posts: 150

Posted: 05:11pm 24 Apr 2021

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http://www.thebackshed.com/forum/ViewTopic.php?FID=2&TID=13733#167708

Edited 2021-04-25 03:31 by Kamak

Kamak
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Posted: 07:01pm 24 Apr 2021

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Back driving the planetary gearbox using the RING gear is possible, all be it with higher torque requirement, but possible with the right sized turbine blade lengths, combined with the larger diameter Blade-Hub (ie. a 29" bike rim)
10:1 Ratio = 100rpm Blade-hub:1000rpm Rotor

Edited 2021-04-25 05:28 by Kamak

Kamak
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Joined: 13/04/2021
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Posts: 150

Posted: 08:16pm 24 Apr 2021

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Hopefully, by early next week, I should have:

1) 1x additional rotor - to start changing out magnets.
2) 125x 5mmx5mmx5mm new N52 Neo magnets (for prototyping)
http://www.thebackshed.com/forum/ViewTopic.php?FID=2&TID=13689#167341
3) 2x 3 phase 1200V 50A rectifier
4) 1x 2ohm 750W load resistor
Edited 2021-04-25 06:27 by Kamak

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