Author Topic: Homemade Axial Flux Alternator  (Read 3790 times)

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MAL

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Homemade Axial Flux Alternator
« on: January 19, 2016, 12:19:12 PM »
I am in the process of trying to design an alternator that can generate 1500 Watts to be installed to a water wheel with some gearing that is not built yet.  The wheel will have between 50 and 70 RPM constantly depending on river level and current speed.
 
My questions are mostly about low RPM alternator design...the wheel can be easily adapted.  I am pretty much settled on an axial flux, but I am not sure if it would be better to stack two 9 coil stators, use one larger 18 coil stator or possibly use a serpantine coil.  I know this is a complex question, but I am sure the answers are here somewhere.   

Rotor size?
Magnet size and quantity?
Magnet wire guage and wind count?
Star or delta?
voltage output 12 24 48?




MAL

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Re: Homemade Axial Flux Alternator
« Reply #1 on: January 27, 2016, 03:26:17 PM »
I am planning to build a floating watter wheel.  My river current speed is about 4MPH.  Barrels will be used on axials with paddles also made from barrels.  I can use 55 gallon or 30 gallon barrels...I have both.  My inclination Is that the 30 gallon barrels will have a higher RPM.  The floating radius is adjustable.  The paddleds can be made any size...2' seems logical because a 55 gallon barrel has a 6' circumference a 30 gallon barrel has a 5' circumference . Barrels will be mounted end to end like rolling pins.  This can be 1, 2,3 or 4 axials with two barrels on each axial.  Calculations on the number of barrels, paddle sizes, paddle number and gear ratio will be very helpfull, but my main question Is about the Axial Flux alternator and how big to build it and what RPM it needs to run eficiently and not over heat.  My usage is about 1500kwh.  I would like to over build the PMA if that makes sense to those who know more about this than me.

Thanks for a great website,

Dave



 

MAL

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Re: Homemade Axial Flux Alternator
« Reply #2 on: February 03, 2016, 03:53:38 AM »
I have a good idea what type of generator that I am planing on using, so now I am trying to calculate how much power is available from 1 barrel. I found this formula on the website posted below.  HorsePower = Constant x Quantity x Height x Efficiency, but that is where it starts to get confusing.

http://www.waterwheelfactory.com/hptable.htm

Constant= (Water Weight lbs.) / (foot-lbs/sec)

Quantity= I am not sure how to calculate the quantity on a poncelet wheel? Is it the gallons of water that pass by the dimentions of the paddles in a minute?  If that is correct I will have 70 ft per minute flow rate x 24" paddle debth x40" paddle width x 7.48 gallons in a cubic ft.

Height= 0  (this will be a floating waterwheel on the Mississippi river)

Effciency= .6  (I am assuming that this would be concidered poncelet wheel)

Am I on the right track with this formula or is there a different method of determining potential power from moving water?

I would be very greatful if someone can set me straight.

Thanks,

Dave

electrondady1

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Re: Homemade Axial Flux Alternator
« Reply #3 on: February 03, 2016, 03:46:30 PM »
you  need to put a prony brake on a single barrel proto type .

 mount it in a such a way as to mimic  how the finished devise will be  positioned.
take a reading and get an idea of the rpm and torque available.
you could put a small alternator on it and measure the output .
then you can scale things up
or go modular an build mutiple devises
maybe sell them to your neighbors
 

MAL

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Re: Homemade Axial Flux Alternator
« Reply #4 on: February 03, 2016, 07:08:42 PM »
Hi Electrondady1,

Would I be able to use my Tork wrench to measure the tork and get usable measurements?  The next logical question is, how much tork does it take to produce?  It is my under standing that these PMA's need more tork after cut in voltage has been reached.  Once I have established how much power is in my barrels, I still don't know what that really means as it relates to how many barrels that I will need.  I know that these are difficult questions...at lest for me, and I appreciate all the time that you have spent on me so far. 

Thanks,

 Dave

MAL

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Re: Homemade Axial Flux Alternator
« Reply #5 on: February 03, 2016, 10:55:08 PM »
I found another calculator, but like the first one it does not make any sense to me.  It sugests that the water wheel blades should only go into the water as far as the head is high.  In my case the head is about 15 thousandths of an inch.  Here is the link if anyone is interested.

http://www.backwoodshome.com/design-calculations-for-no-head-low-head-waterwheels/

electrondady1

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Re: Homemade Axial Flux Alternator
« Reply #6 on: February 04, 2016, 06:32:57 AM »
there is a search engine  at the top right of the page
  try searching "undershot wheel"
 that is basically what your thinking of building.


skid

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Re: Homemade Axial Flux Alternator
« Reply #7 on: February 04, 2016, 11:02:14 PM »
I attached a link to an undershot wheel calculator in my waterwheel thread ...

http://www.borstengineeringconstruction.com/Undershot_Water_Wheel_Design_Calculator.html