Author Topic: high voltage axial flux (Read 1863 times)

fanman · « **on:** March 14, 2006, 01:16:24 AM »

hello everyone fanman here, well its about 8pm here in michigan and it is very breezy tonight, my axial flux is close to the ground and kind of in the pickers, so the wind needs to be straight out of the west for a good run, and tonight its pretty westerly, and of course i found a few things i dont care for that i will fix later, the pipe over pipe does make some banging noise, i need to make those clearances a bit smaller, the tail is not long enough for the machine, or heavy enough,my blades are 16' dia and the generater is offset about 8" so i think those two items make the machine furl a little soon, other than that there is no complaints, the day i put it up i seen 18 amps, thats 2500 watts, tonight ive seen 33 amps,or 4600 watts, that is really great if you ask me, i did at one point go check the stator for overheating, but it wasnt even warm yet, i will be moving soon and i will put it in a great spot for wind, and then that will be the test for sure. so far so good, thanks guys have a great day.

MrBill · « **Reply #1 on:** March 13, 2006, 07:27:39 PM »

Fanman thats a nice looking machine....I dont know a lot about calculating power output yet...Could you explain in lay terms how you arrived at the 4600 watts..Thanks.

Nando · « **Reply #2 on:** March 13, 2006, 07:39:03 PM »

WATTS @ 18 AMPS
/18 = 138.9 VOLTS
WATTS @ 33 AMPS
/33 = 139.39 VOLTS

This means that he has a 120 volts battery bank and the wind mill is designed to produce a high voltage to charge the batteries and this way, to have a house hold fed with a 120 volts system, easy to convert to 120 VAC MSW wave form, which he has done.

It is good to see at least one doing the proper wind mill design, instead of using low voltage and Heat generator inverters.

Nando

Nando · « **Reply #3 on:** March 13, 2006, 07:42:27 PM »

correcting display of my past message

2500 WATTS @ 18 AMPS
2500/18 = 138.9 VOLTS
4600 WATTS @ 33 AMPS
4600/33 = 139.39 VOLTS

Nando

harrie · « **Reply #4 on:** March 13, 2006, 08:04:07 PM »

very nice Fanman, what kind of rpms are you working with at cutin, maybe you posted that already, but if you did, I missed it. also, how many batterys are you using, 10? Very interesting!!

harrie · « **Reply #5 on:** March 13, 2006, 08:25:55 PM »

forget my questions Fanman, I looked in your postings and found the answers. continue to keep us posted.

Ungrounded Lightning Rod · « **Reply #6 on:** March 13, 2006, 08:51:00 PM »

well its about 8pm here in michigan and it is very breezy tonight

Where in Michigan?

The whole of "shotgun" and the lower part of "rifle" has a severe wind advisory.

Here's a link to the Weather Underground severe weather map.

You might get a chance to tune your furling system tonight if you're in the lower half of the LP. B-)

(At least the tornado watch is over.)

hvirtane · « **Reply #7 on:** March 14, 2006, 01:52:23 AM »

This seems to be a really good system.

Thank you for the pictures.

What is you opinion about

making an inverter 120 DC -> 110 AC

according to your plans?

(From your earlier post.)

Is it possible to make it by

such kind of people, who have got

really little experience

concerning building electronic

devices? I mean that they can

only solder things together

according to the drawings.

- Hannu

BigBreaker · « **Reply #8 on:** March 14, 2006, 06:33:07 AM »

Nando - why is MSW so much easier than a true sinusoid? I'm picturing the circuit and it seems as simple as setting the pulse width off a small lookup table. You are a circuit guy (as demonstrated in many posts)... why the compromise?

It could be I'm thinking of a different circuit. Mine would need 1.5-1.7x the 120 volts DC to get a true sine wave with some tricks.

Seems like a lot of people are leaning towards 120 volts systems. There are some really nice features to them. Perhaps we need an electronics section and a circuits library?

Nando · « **Reply #9 on:** March 14, 2006, 10:38:28 AM »

MSW is simple because is just a switch with some time ON-OFF and polarity requirements.

For a true Sine Wave POWER generation a new set of rules and a lot of additional electronic parts are needed.

First a dual bipolar voltage is needed like 200+ and 200- volts.

This dual bipolar section is almost equivalent to the MSW but additionally we need:

A bipolar switch to go between the positive and negative voltages with variable duty cycle following a sine wave reference, feeding a power inductor and filtered by a high voltage and high capacitance AC capacitor

Feedback circuitry and current protection, as well as, current re-direction due to the external loads that can be resistive, capacitive or inductive.

Sine wave generation, start up procedure, current limiting and over all system protection, the addition of several low voltage isolated supplies to power the diverse sections that sometimes need to be 500 + volts isolated.

In a sense, a True Sine wave power source is in electronic parts 3 to 5 times the parts that a MSW may have for the same power.

Just the highlights.

I am developing and finishing one that has 1500 volts isolation between input output voltages, plus another set of requirements that make the job very difficult.

Nando

Nando · « **Reply #10 on:** March 14, 2006, 01:47:33 PM »

HANNU:

I am not sure that you directed your message to me, so I am assuming that you did.

YES, using a common and small DC/AC inverter, ( 75 to 100 watts capacity) and buying a couple of small PWM supplies, one to charge the small EC/AC inverter battery, if needed and another smaller PWM 12 volts output at about 0.5 amps plus 2 or 4 transformers and High Current MosFets, or IGBT with the proper voltage range, one can make a TRANSFORMERLESS MSW Inverter capable of several KILOWATTS up to 10 KW or so.

Also the design is so flexible that it can be done for 115 Vas or 230 Vac volts, if the battery bank is high enough, including an automatic 50 or 60 Hz as defined by the small DC/AC inverter output frequency.

Fanman talked about it and reminded me what I designed around 8 to 10 years ago that only 3 were built at the time.

I am trying to get some free time to fix the desk computer to be able to draw the schematics -- right now I am too busy with consulting jobs, also I have been asked to present it as an article for a magazine.

Decisions and more decisions.

Nando

hvirtane · « **Reply #11 on:** March 14, 2006, 03:22:56 PM »

Nando,

what you are describing sounds really nice.

Maybe it would help also you article

writing, if you would little by little

publish the design here as a diary?

When the diary would be ready, you

could publish it as an article as well?

Fanman actually also wrote that he

has got drawing he could sell:

(from Fanman's earlier post)

-----------------------------------

... i do have plans that i will

sell for $40.00 each it is

a 4000 to 6000 watt mosfet

driving inverter and is

very easily to assemble

all with radio shack componants,

mostly the mosfets you must

order from digakey,

this is really a great inverter

the only one thing that it

doesn't have is regulation,...

-----------------------------------

- Hannu

fanman · « **Reply #12 on:** March 14, 2006, 05:53:09 PM »

hannu

hey this is fanman, i was reading your guys conversations earlier and i will tell you that this inverter is pretty easy to put together, i put it together a few years back, and i didnt have a whole lot of electronics experience, i just took my time and double checked, i mean triple checked everything, and wow the dumb thing fired up and worked really well, im still using it today, and im still not really experienced like i would like to be, but hopefully nando gets his machine running and we can all work together and make this thing happen,and by the way i will not sell those plans to anyone, they are free to whomever wants them, well probably a couple bucks for shipping thats all, let me know eh?

fanman · « **Reply #13 on:** March 14, 2006, 06:05:57 PM »

harrie

i will answer this anyways i have the machine cutting in at 110 rpms or so, yes thats a little fast for a 16' prop but i couldnt get anymore turns of wire in there for a bit more voltage, but i think i may have conquered the stall problem some people seem to be having, when it reaches cut in the amp meter goes right up very quickly,thats pretty neat. my batteries are of the forklift type 4'x4'x24" high 36 volt with 2 volt cells, one of the batteries is a parreled 36 volt, so i took the batterie packs apart and configured my own 120 volt bank at 1375 amp hours,they were used so the auctual capacity is some less but they work great, and were very reasonable for what they are, i got them out of a gm plant in texas. 4200# each. talk to ya later.

BigBreaker · « **Reply #14 on:** March 15, 2006, 12:21:22 PM »

Gotcha. I read up on MSW and it does seem more straight forward. I didn't realize what a compromise it is in terms of waveform. The upside is that it is VERY simple to generate and most gadgets do not seem to fussed by the squarish harmonics.

The PWM true sinewave version is more complicated at first blush and doublely so (or more) after all the protection and regulation circuitry is added. That final filter cap has some serious requirements. Certainly you'd want to use a bank in parallel. I'm an EE type like you so that's where I see a lot of the fun.

amiklic1 · « **Reply #15 on:** March 18, 2006, 01:58:42 PM »

How can I order those plans here to Croatia?

Thanks

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