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Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 05:16pm 10 Sep 2009

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I am yet another new member that has veiwed this site for some time with great enjoyment of what others have done.
I would like to contribute a idea on dump load resistor
design after a little testing.

What i need is some average and maximum output figures for typical F&P generators.

12v, 24v, 48v, single and double stator units.

My intensions are to use this information on dump load resistor construction and testing.

My aim is reliable, easy to build, ultra low cost, dump load resistors.

If all works out with the design than i will post a "how to make" should there be an interest in yet another "Load Resistor" construction idea.

Sometimes it just works

Smart Drives

Senior Member

Joined: 06/07/2009
Location: Australia
Posts: 115

Posted: 12:27am 11 Sep 2009

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Maximum power from a 12v system is 600 watts , maximum power from a 24 & 48v system is approx 1kw.
If you work on those values you should be fine.

single stator.

Cameron.

All smart drive parts sold
Custom built turbine parts on
Multicam flatbed CNC Router

fillm

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Joined: 10/02/2007
Location: Australia
Posts: 730

Posted: 02:59am 11 Sep 2009

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Smart Drives said Maximum power from a 12v system is 600 watts , maximum power from a 24 & 48v system is approx 1kw.
If you work on those values you should be fine.

single stator.

Cameron.

I think these figures for a wind turbine are not correct Cameron , mabe on a hydro or on a test bed at 1000+ rpm , where did you get these output figures ?

350watts at 48v/24v is about the max for a single stator on a windmill..

PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits

Smart Drives

Senior Member

Joined: 06/07/2009
Location: Australia
Posts: 115

Posted: 08:42am 11 Sep 2009

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I have a full set of graphs from ecoinnovation showing all possible outputs.
It doesn't matter if the results are from hydro, test bed or wind we are measuring the output at a certain RPM.
And you asked "What i need is some average and maximum output figures for typical F&P generators."
You haven't specified which way you are wiring your motors up. There are too many different wiring possibilites to give you average results so i gave you Maximum.
12v using a 100SP or 80P (star or Delta) but star has a more gradual rise from a lower rpm.

24v using an 80SP (delta)
48v using an 100P (delta) startup is way to high though.

Cameron.

All smart drive parts sold
Custom built turbine parts on
Multicam flatbed CNC Router

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 11:06am 11 Sep 2009

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Hi all
Cameron. Thanks for the input.

I cannot fly a mill where I am, but have built one for a
friend 400km away. F&P
Also played with several rewires of stators on a basic
test jig.
None if which I have handy.
What I was asking was some figures that I could construct
a load resistor to suit 12, 24, 48, volt F&P systems.
(but not limited to)
The design has the resistors in parallel and can be
switched in stages if chosen, or as a resistive block.
(up to the users construction )
For average power I was after a ball park figure, for an
average day of steady wind with the batteries full. (
pick a figure?)
Maximum power was what would be needed under high wind
conditions with full batteries.
I know the question is a little open ended with various
styles of setups, but what would you what in a load
resistor bank for your mill? And in what stages would you
switch in more resistance if able to.
If anyone else would to post their mill requirements for
load resistors than it would give me a better guide
overall.

Is there any interest in using the dissipated heat in
water, and how would you like to use it?
Preheat to HW/S, or warm water in the shed, etc??

What I want to do is post something workable rather than
a scratch in the pants idea.
I need some figures to work to for a ball park, as the
end product is up to constructor and their mill
requirements.

Any input welcome.

Sometimes it just works

GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127

Posted: 12:02pm 11 Sep 2009

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Hi Downwind,

My research with a F&P windmill points to a different approach to a diversion load. The reactance limiting, coupled with decent furling, and the usual setup with overdriving with the blades can be easily controlled with a voltage controlled relay, that just overloads the windings, on the AC. You actually dont load the battery side at all. If you want to heat water, then divert AC to the heaters This won't be the most efficient, but this is waste power.

I have successfully used a 7stage loading up to 3.5kW on a Skystream AC coupled windmill with batteries. The diversion loading is on the 240VAC as well. I was told today, that this setup was able to recharge an 830Ah 24V flooded battery system, from well into the red electrolyte SG, to fully charged top of the green SG in about 7 hours. This was probably 20kWhr, with just bulk charge, and tapered absorbtion to 29.2V. This is a houseRE system, with daily cyclic battery use.

The successful use of all windmill power is difficult, due to the nature of wind. If you wish to heat water, then you still need a changeover system that diverts to an alternative when the water is hot. Either turn the windmill OFF, or heat air for extended reliability, when the battery is full.

Turning the windmill OFF in overvoltage/storm conditions, with simple 20-30% full power diversion loading is a good compromise to multi stage diversion loading.

Gordon.

become more energy aware

Downwind

Guru

Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 02:06am 12 Sep 2009

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Hi All.
Gordon, Thanks for the input, and I would like to see a layout of the circuit you use if it is freely available.

It is not that I wish to heat water or even require to dump power ( as I pay for mine) But would like to post a way of building very cheap load resistors that can heat water or air, for those who wish to use resistors for loading.
I just wanted some figures to work to, so as to ensure the design can handle an average (whatever that might be) mill in all wind conditions.
All things can be made variable, but rather than pulling some figures out of ones underpants to work to, i was after some real operational power figures to design to.

This project is of no use to myself and I am only doing it for the sheer buggery of building it, to take photos to post it, so others may benefit from the idea.

Downwind.

Sometimes it just works

fillm

Guru

Joined: 10/02/2007
Location: Australia
Posts: 730

Posted: 06:52am 12 Sep 2009

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Why not just post how to make a variable dump load / resistor from 100w to 1000w , if its variable then does it really matter about circuits and max outputs as you can change the load to suit your system ..

Looking forward to seeing what you come up with...

PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits

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