Author Topic: Mini CNC Blades  (Read 5242 times)

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SparWeb

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Re: Mini CNC Blades
« Reply #66 on: July 21, 2022, 03:03:05 PM »
.I'm going to bring the air gap back from 1/8" back to a 1/16".

Closing the gap will only raise the generator's torque curve, slowing the blades even more.

Adding some resistance will help.

The real problem is I think the blades are undersized. 
« Last Edit: July 21, 2022, 03:13:17 PM by SparWeb »
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taylorp035

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Re: Mini CNC Blades
« Reply #67 on: July 24, 2022, 08:34:34 PM »
As I was predicting, the blades not spinning fast enough was the real problem.  I lowered the battery voltage from 3.59v to 3.38v and then reduced the air gap. This made it cut in at a much more reasonable wind speed (probably 9-10 mph).  I need to make a new base for it since it likes to warp when it gets hot and the bearing supports end up becoming non-perpendicular to the shaft and there ends up being extra drag.  I also need to do a bit more clearancing in the alternator where the magnets hit the glue.  It made 1.75 ah in 4 hours today, which may not sound like a lot, but it's better than the last few attempts.

I still want to make some new blades since these still seem fairly lackluster.
« Last Edit: July 24, 2022, 09:19:47 PM by taylorp035 »

MattM

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Re: Mini CNC Blades
« Reply #68 on: July 27, 2022, 07:44:09 AM »
I don't think you will find any use for <10 mph winds.

taylorp035

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Re: Mini CNC Blades
« Reply #69 on: July 31, 2022, 09:23:32 PM »
I added another 1.5 degrees to the blade pitch last night, now for a total of 7 degrees out at the tips.  I also touched up the mating face to the hub them so they spin exactly in the same plane at the tips so the wake of the previous blade doesn't interfere.

I was also finding my front bearing would try to walk backwards on the shaft, causing it to be in tension and causing a bunch of extra rotational drag.  I shifted the bearing support tower a bit and it seems to be a big improvement.

taylorp035

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Re: Mini CNC Blades
« Reply #70 on: August 03, 2022, 08:35:40 PM »
It did much better today with the 7 degrees of pitch.  It made 3X more amp hours than my best day of flying it with the 3.5 degree or 5.5 degree angle and it wasn't super windy today.

SparWeb

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Re: Mini CNC Blades
« Reply #71 on: August 04, 2022, 01:35:42 AM »
Well done, good to hear.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca