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Gizmo
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Posted: 22 May 2018 at 10:39am | IP Logged Quote Gizmo

Guys dont ask me to delete old posts, I'll probably delete the wrong one!

No, once someone has replied to your post, you can not edit it. Obviously.

Fred: "Bill is a nasty person!"
Jo: "Not true!"

Fred edits his post to say "Bill is a nice person"




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DaveP68
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Posted: 22 May 2018 at 10:53am | IP Logged Quote DaveP68

Hi Glen

Well summed up. The main reason "delete old posts" came up is there is very almost no drawings on here for wiring in Delta mode, if you get a chance to read why that happened.

There are plenty of drawings of how to wire in Star in different configurations and only one for Delta which looks confusing too me.

BarkyJ

Here is a photo of a 2x6c wired in delta connected to a capacitor doubler.



Sorry it's low resolution again but the wiring R-B, B-Y & Y-R should be more obvious.

The drawing you have looks correct just very hard to see the blue wires combining the 4 groups of 3x poles.

David
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BarkyJ
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Posted: 22 May 2018 at 11:15am | IP Logged Quote BarkyJ

Thanks David

Yeah the very faint wires were actually coloured Yellow, Red and Blue in the drawing I did on paper, but they did not scan that way at all, and came out light blue as you say.

Thanks for confirming it is correct though. I will improve it and post another one in due course.

So the reason you wired it like you do (taking my latest hand drawn drawing for example), compared to say my first hacked drawing (the complete one, not the disputed one I want deleted), is it down to efficiency, or is it just simply easier to wire it that way in practice?

@Gizmo - as Dave said, the reason I want that first image deleted that I emailed you about, is because its wrong, and if people come along later or google images picks it up, then its going to be available and its just not right. It was an intermediate step to see if I hand the bottom 1/4 of it hacked correctly, so 3/4 of it is wrong. The 2nd image I posted is correct in theory. Then the last hand drawn one I guess is wired as correct in practice.
All down to the fact there are no delta drawings that I can find, and for a windmill noob like myself, getting my head around things without a reference is a little tricky.

@Dave - 2x6C Delta looks nice and simple :)
Is there a write up on the cap doubler?
Is the link I put of 'Gordons Caps' referencing it correctly, or is your version different again?
https://www.thebackshed.com/windmill/articles/GordonsCapMod.asp
Just trying to figure out how they are wired up.

Thanks
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BarkyJ
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Posted: 22 May 2018 at 12:15pm | IP Logged Quote BarkyJ

See if this is any better



Potentially not, haha.

Here is the original again, but fixed the faint lines. Might be easier to see since it shows the original copper wires over the poles, vs the wires you add in the centre.



Edited by BarkyJ on 22 May 2018 at 12:28pm
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DaveP68
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Posted: 22 May 2018 at 3:15pm | IP Logged Quote DaveP68

Brilliant nice drawings, couldn't have done it better myself.

We need to get some of these on the main pages for others new to this site as wiring Delta ins't as straight forward as Star. I personally only wire my stators in Delta mode.

The main reason for wiring this way is purely for electrical symmetry. Each group of coils making up the Delta triangle in the circuit has the same resistance. Also using the larger gauge wire is only for joining the 4x groups of Delta windings together with them being double the length of the connection next to each other.

I can take a Star stator open circuit and drive it with a drill to over 1000 RPM take an input power reading of the drill. Then take another stator wired Delta repeat the same test and get an identical reading input power reading.

This means there is Zero imbalance in the Delta circuit and ALL currents in the Delta loop sum to Zero.

I don't used capacitor doublers anymore. The drawback of capacitor boublers is the extra system loss due to how they work. The loss at best is 15 % but typically more closer to 20 %.

Don't get me wrong there is a place for capacitor doublers when using them for direct battery charging.

The resonance capacitors provide a much better power output improvement along with amazing extra torque. The efficiency drop is in the range of only 5 % sometimes even less. One other big advantage is they almost follow the wind power curve with the way they start to produce lots of extra power for only a modest increase in RPM.

Resonance capacitors are best used in high voltage AC mode connected to a MPPT inverter charger of Grid Tie Inverter.

I've test resonance capacitors on a 1x12p Delta stator into my dynamic brake circuit and extracted around 900 W at 400 RPM. This same circuit has been modified to provide MPPT which is exactly what you are trying to do. My circuit has run with a 28 ohm resistor very close toe the 240 V 29 ohm element you also have.
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Gizmo
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Posted: 22 May 2018 at 3:51pm | IP Logged Quote Gizmo

If you guys come up with a set of drawings you are all happy with, I'll put them on the main page and give credit where credit due.

When I originally drew those pictures, I used a CAD program to draw the stator, saved as a DXF, and imported into Paint Shop Pro 7 ( old school ), where I added colour, text, etc. Very long process, but the results were OK for back then.

Here's a tip for making uploaded pictures bigger and clearer on the forum. Save them as a GIF instead of a JPG. GIF's suit line art detailed drawings better than JPG, but lack the colour depth of JPG. So GIF for diagrams, JPG for photos. The forum also resizes GIF's to a bigger size than JPG's, so you loose less detail.

Glenn



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BarkyJ
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Posted: 22 May 2018 at 4:26pm | IP Logged Quote BarkyJ

Dave - Ah, so 2 different things. Cap Doubler vs Resonance Caps. Gotcha.
I wont consider Caps at this stage anyway, just adds to the complexity before I even have something working. Just curious as a side topic though.

So just to go back a few steps.
MPPT, which is what was designed for Solar originally, if I am not mistaken, to extract as much power as possible out of the cells, right?
From what I had read, and this might be incorrect, that alot of MPPT controllers are not suited for Wind, potentially due to how slow things change when load is applied, and how erratic the output can be at the same time - but maybe this is just someones optinion rather than fact.
So a MPPT controller takes what inputs exactly?
RPM?
Voltage?
anything else?

So my next step, does this sound reasonable or is it uncecessary:
1) Get a stator wired in Delta.
2) Set up my controller to have manual input mode for load PWM, controllable from the screen, so I can vary it up and down manually.
3) Test various RPM's one at a time, and manually apply load to find the peak power for each RPM.
4) Plot all the peak Power figures on axis of RPM's / Voltages and Load, and then come up with an equation for peak power, so I can figure out what load to apply at a given RPM/Voltage
5) Implement controller to follow equation for any given RPM/Voltage to apply the load to attempt to achieve the most amount of power at that particular wind strength.

Does that seem somewhat reasonable? Or am I still not quite understanding things right...

My current controller is easy to change given its all software controlled, I just need a bit of a nudge in the right direction as to if what I am thinking is actually what I should be aiming for.

Oh I found a new FET which should allow me to increase the voltage further.
IPP023N10N5

Look forward to hearing from you again
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DaveP68
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Posted: 23 May 2018 at 3:09pm | IP Logged Quote DaveP68

I'll do my best to answer these questions for you and for the benefit others who read this post.

Solar MPPT algorithm works different to Wind in one main regard, the voltage must increase to a relatively high set level before much current can be taken.

Please refer to this Solar MPPT Volts vs Current graph




Wind MPPT is very different, in that any increase in working voltage from the PMA (F&P stator) MUST be in proportion to the shaft RPM. The current must rise at a rate 2x the increase of RPM which will be in proportion to Shaft Torque.

A Wind MPPT controller usually only takes the rise/fall in voltage from the PMA as it's main input and adjusts the current in order to achieve "Maximum Power Point Tracking". The measurement of RPM can make this process easier as a 2nd reference input.

Add resonance capacitors into the equation and this changes everything that I've stated above, but the increase output power that they provide can't be over looked.

Edited by DaveP68 on 23 May 2018 at 4:40pm
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