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Forum Index : Electronics : Backshed Piclog - This is great stuff

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SparWeb

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Joined: 17/04/2008
Location: Canada
Posts: 196
Posted: 06:00am 02 Dec 2008
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Lots of wind all day; a new weather system is rolling in. Knowing it was coming, I left the data logger running all day. I came home after work to see this:



Sorry graphic isn't very clear: the PicLog had recorded 3667 WattHours, and that was only at 7 PM. It's about 11PM, now, and the count just crossed over 5000 Whrs. That's the most energy I've ever recorded collecting in a day. It's about a quarter of my house's daily consumption.

Thanks again to they boys in the Backshed for designing a datalogger so easy to build.

Steven T. Fahey
 
GWatPE

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Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 06:20am 02 Dec 2008
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Hi sparweb,

a mill doing 1000rpm. this is a screamer.

I assume as the battery is at 27.5V, that much of this power has gone to diversion loads.

Gordon.
become more energy aware
 
Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5012
Posted: 06:35am 02 Dec 2008
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Hey Sparweb

Glad to see the Piclog is working for you. That RPM AC measurement can be a bit tricky to get right.

Thats good power your making.

Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
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oztules

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Joined: 26/07/2007
Location: Australia
Posts: 1686
Posted: 12:08pm 02 Dec 2008
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lets see... 1050 rpm, 8' prop and 36kph wind..... thats ... 12.5 TSR.

So,1/tsr=.079
Atan of that is about 4.5... subtract the tip angle (maybe 4 deg....) So .5 degree angle of attack..

I think your well out of stall

Or, methinks there's still some filtering to be done on the rpm side of things.

Nice to see it working well for you. Your workmanship is a pleasure to see (had to ferret out the prop size from F/L).. nicely shaped prop. (seen from the cheap stalls here.)

That will light a big string of LEDs on the Christmas pole this year (are we doing it again?), or keep the horses in hot water for a while in the manner they've become accustomed to recently.

..........oztules Edited by oztules 2008-12-03
Village idiot...or... just another hack out of his depth
 
Dinges
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Joined: 04/01/2008
Location: Albania
Posts: 510
Posted: 05:08pm 02 Dec 2008
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Is it the 3hp conversion that's producing all that power?

5kWh/day...Very nice! Would be enough to satisfy 80% of my power use. And that includes electric waterheating

Moments like these that makes one proud of the fruits of all that hard work eh?

But... think of all the things you could power with a 15' 10hp conversion at windspeeds of 36 km/h; about 20kWh/day energy! The horse's water would be hot enough to make tea

Peter.
 
SparWeb

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Joined: 17/04/2008
Location: Canada
Posts: 196
Posted: 07:55pm 02 Dec 2008
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HEHE!

I knew that RPM would catch your eyes.
Yes indeed filtering is necessary when reading the AC directly. One moment it's 540 RPM, the next moment it's 1050. Audibly nothing's sped up, no increase in output, and this motor conversion does not have reactance-limiting that would make it possible to obtain 500 Watts at 500 RPM and 1000 RPM.

Someday I'll put a hall sensor or a reed switch up there, but for now it's too easy to just tap the AC.

Yes, too, about the 27.5 voltage: the water trough heat was ON @ 1500W. Plus all barn lights I was sucking about 100 Amps out of the batteries. Maybe I should get those christmas lights up again!

Tea for the horses! Hot baths! What luxury!

Steven T. Fahey
 
GWatPE

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Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 09:46pm 02 Dec 2008
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Hi sparweb,

the piclogs that I made, and phill has 2, do not seem to have linearity problems, or noise pickup. I used a slightly different technique to Gizmo, as I did not want to make a direct copy. Remember the F&P, that phill has, has an output frequency of 28cycles per rotor revolution. His setup is 48V as well. He has said that the sensing drops out below 10rpm. I would expect problems at low rpm, and not at the higher rpm.

Gordon.
become more energy aware
 
SparWeb

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Joined: 17/04/2008
Location: Canada
Posts: 196
Posted: 09:54pm 03 Dec 2008
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4 pole motor conversion. Low Low bargain basement frequency.

At 500 RPM the frequency of the AC output is about 33 Hz.

I haven't seen many oscilloscope traces of motor conversions electrically loaded and charging batteries, but from what I can tell there will be a spike at every ON in the diodes, and it might also be that the zero-crossing isn't a clean transition, either.

Troublesome waveform, not trouble with the PicLog. It's great.

Steven T. Fahey
 
GWatPE

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Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 11:06pm 03 Dec 2008
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  SparWeb said  from what I can tell there will be a spike at every ON in the diodes


Hi sparweb,

the spike if there, should only affect the rpm signals, if there is low sensitivity in the current to the opto-coupler LED.

Gordon.

become more energy aware
 
Dinges
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Joined: 04/01/2008
Location: Albania
Posts: 510
Posted: 06:47am 04 Dec 2008
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  Steven said  
I haven't seen many oscilloscope traces of motor conversions electrically loaded and charging batteries,[/quote]
I have (only) one picture of that situation, of the 500W conversion in the lathe-test running into a 6V and 12V battery:

http://www.anotherpower.com/gallery/album69/blue_boy_charge_ 6Vdc_300RPM
http://www.anotherpower.com/gallery/album69/blue_boy_charge_ 12Vdc_300RPM

These are the waveshapes as measured on the AC-side of the rectifier; on the DC side it's basically a horizontal line.

Peter.
 
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