Author Topic: 48V Direct Drive MPPT Turbine  (Read 20361 times)

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tecker

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Re: 48V Direct Drive MPPT Turbine
« Reply #33 on: May 13, 2013, 07:57:38 AM »
The noise is a warble of the rotors I get a similar noise when  the stators are under max load . I used some Locktite on the rotor spacers and it quieted mostly  but is still there.
Good looking Machine
« Last Edit: May 13, 2013, 08:03:40 AM by tecker »

ChrisOlson

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Re: 48V Direct Drive MPPT Turbine
« Reply #34 on: May 13, 2013, 09:48:42 PM »
The noise is a warble of the rotors

Actually, it's harmonics in the generator winding at 25-30 Hz, which is basically cut-in speed to about 120 watts.  After that it's quiet except for a slight amount of hum from the generator.
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SolarFlare

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Re: 48V Direct Drive MPPT Turbine
« Reply #35 on: July 30, 2014, 08:49:01 PM »
Hi Chris!
Did you end up putting a damper on the stator? If so, what was your approach? Thanks! SFlare


I've had so many emails and phone calls on this machine that I'm going to be providing AutoCAD drawings of some of the parts on the build website.  People can download the AutoCAD drawings and put them on a memory stick and take them to a CNC machine shop where they can plug them into their CAD/CAM system and cut the parts.

Most people are worried about the hole placement on the generator rotors and stator support.  And while there is a fair amount of leeway there, attention has to be paid to accurate cutting with generator rotors for proper balance and such.  When the turbine rotor is on one end of a shaft and the generator on the other you don't want a couple generated due to improper dynamic balance, even though you have perfect static balance on both ends, that will cause a severe "wagging" on the tower.

Providing the drawings so the parts can be CNC cut will help insure that things are accurately made for the homebuilders out there that want to build one.

I've seen this new machine running at 3,100 watts and 52.6 amps to the battery @ 144 volts controller input with a 3.2 meter rotor on it.  It doesn't seem to have much advantage over the geared ones at lower wind speeds.  But once the wind gets over about 12 mph it makes slightly more power than the geared machines that I've built.  Mainly due to slightly better generator efficiency in this one and running at higher voltages than the geared ones are designed to run at, so less loss in the wiring and rectifier.  It's on its second stator revision right now.  For a 3.2 meter I could make the stator just a tiny bit more efficient by reducing the turns in it.  But the stator that's in it will be a good match for a 3.5 meter rotor.  As soon as I get my 3.5 meter rotor that I got in the shop rebuild and repainted it will be going on this machine for testing.  I expect to get close to 3.5 kW peak from it with the 3.5 meter rotor on it.

The generator in this turbine is a bit more noisy, though, compared to the geared machines.  The geared machines run pretty much totally silent except for blade noise.  This thing hums a tune on the tower all the time, due to operating at much lower current frequency than the geared generators for any given output.  Once this thing gets above about 200 watts it's fairly quiet except for a distinct hum from the generator.  But below 200 watts there's a couple places in the speed range where the harmonics in the winding reach a natural frequency that amplifies it and it's loud enough to be easily heard from 200 feet away.  When I get it down I have to look at installing a damper on the stator to stop that.
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fabricator

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Re: 48V Direct Drive MPPT Turbine
« Reply #36 on: July 30, 2014, 09:37:01 PM »
I don't know if Chris will see this, he's pretty busy right now with farming stuff, I do know he took down all his mills and bought a pretty big Bergy mill.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

SolarFlare

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Re: 48V Direct Drive MPPT Turbine
« Reply #37 on: July 31, 2014, 09:25:28 AM »
I don't know if Chris will see this, he's pretty busy right now with farming stuff, I do know he took down all his mills and bought a pretty big Bergy mill.
[/quote


Are you sure he bought a Bergy?

fabricator

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Re: 48V Direct Drive MPPT Turbine
« Reply #38 on: July 31, 2014, 12:14:33 PM »
Yep, positive, I believe it's on an 80' tower.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

kitestrings

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Re: 48V Direct Drive MPPT Turbine
« Reply #39 on: July 31, 2014, 10:23:33 PM »
Hey Fab, SFlare,

Did he bring in utility power?  Last knew he'd upgraded to a pretty slick Schneider inverter set-up, had batteries, two gennys...

I know the Bergey Excel can is available in a 7.5 kW battery charging configuration; 48V IIRC that might be it.

Maybe if we all get speculating he'll pop in long enough to set us straight.

~ks

fabricator

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Re: 48V Direct Drive MPPT Turbine
« Reply #40 on: August 01, 2014, 08:08:19 AM »
Oh yeah, he's got all the latest Schneider stuff, they made him certified field tester so he gets it all for free for being a guinea pig.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.