Author Topic: Anybody guess what this is going to be???  (Read 17698 times)

Offline cfellows

  • Full Member
  • ****
  • Posts: 1700
Anybody guess what this is going to be???
« on: June 12, 2013, 09:50:18 PM »







Here's a hint...



It's going to be an air core dynamo, obviously.  I started with a 4" square piece of 1" thick, HDPE (High Density Polyethylene).  Also sometimes called Seaboard. 



It's used a lot in the boating industry.  It's pretty rigid, but does have some give to it.  Machines like a dream.  I decided to make the core out of plastic since it won't put out a lot of power and, more importantly, the Fairbanks compressed air engine should have enough power to run it and light up a few LED's.  Here I'm drilling a 1/4" hole in the center.



Next I cut circular grooves on both sides.  These grooves will form the coil winding channel.



I changed rotary tables and started whittling away everything that didn't look like a dynamo core.



This will be a single phase AC alternator.  I used a lot of the information provided by Manfred Albert over here:

http://www.homemodelenginemachinist.com/f23/dynamo-build-castings-17756/

I'll be using #24 magnet wire, hoping to get 60 or 70 turns per coil.  They will all be hooked in series.  Not all sure what kind of voltage and current I'll get out of this thing, but since LED's will run on about 3 volts or less, I think it will be sufficient.

Chuck
So many projects, so little time...

Offline vcutajar

  • Full Member
  • ****
  • Posts: 2482
  • Marsascala, MALTA
Re: Anybody guess what this is going to be???
« Reply #1 on: June 12, 2013, 09:55:01 PM »
This is going to be interesting.

Vince

Offline tel

  • Administrator
  • Full Member
  • *****
  • Posts: 1657
  • Bathurst District, NSW, Oz.
Re: Anybody guess what this is going to be???
« Reply #2 on: June 12, 2013, 09:59:28 PM »
Interesting indeed - and a very nice start!
The older I get, the better I was.
Lacerta es reptiles quisnam mos non exsisto accuso nusquam

Offline dale

  • Full Member
  • ****
  • Posts: 10
Re: Anybody guess what this is going to be???
« Reply #3 on: June 12, 2013, 10:12:13 PM »

Oh I get it! The engine turns the dyno,the dyno powers up the air compressor, the compressor supplies nourishing air to the engine! very ingenious :Lol: Seriously another great project, always interesting and informative

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13643
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: Anybody guess what this is going to be???
« Reply #4 on: June 12, 2013, 10:43:25 PM »
Will definitely be following along Chuck....nice start on it!!

Bill

Offline stevehuckss396

  • Full Member
  • ****
  • Posts: 1396
  • Sterling Heights, MI
    • Steve's Miniature Sparkplugs
Re: Anybody guess what this is going to be???
« Reply #5 on: June 12, 2013, 11:04:27 PM »
I don't know Chuck! Something like this?





Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline Bezalel

  • Full Member
  • ****
  • Posts: 376
  • - Skype:Bezalel2000
Re: Anybody guess what this is going to be???
« Reply #6 on: June 12, 2013, 11:31:48 PM »



Chuck


nicely done  :ThumbsUp:


I'll be very interested to see what sort of efficiency the air core has,


Of course you're gunna knock up an iron one, just  for the comparison aren't you?    :stir:


Bez
Queensland - wet one day, humid the next

Offline zeeprogrammer

  • Full Member
  • *****
  • Posts: 6375
  • West Chester, PA, USA
Re: Anybody guess what this is going to be???
« Reply #7 on: June 13, 2013, 12:01:16 AM »
"Anybody guess what this is going to be???"

Mine?  ;D
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Don1966

  • Full Member
  • *****
  • Posts: 5996
  • Morgan City, LA (Along the Gulf Coast)
Re: Anybody guess what this is going to be???
« Reply #8 on: June 13, 2013, 12:03:55 AM »
Very interesting Chuck, I will be tagging along. Electrical devices always interest me.

Don

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13643
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: Anybody guess what this is going to be???
« Reply #9 on: June 13, 2013, 12:11:00 AM »
Nice try zee....this from someone who has to wait till T goes out of town to to have chicken cheesesteak  :lolb: :lolb:

Bill

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12610
  • Hampshire, england.
Re: Anybody guess what this is going to be???
« Reply #10 on: June 13, 2013, 07:27:01 AM »
Chuck, I would like to be following this along but I should have said earlier that my internet provider  :hammerbash:  :hammerbash: won't let me see your photos because it has decided to block acess to where ever you are hosting them.  :-\

Jo
Usus est optimum magister

Offline Bezalel

  • Full Member
  • ****
  • Posts: 376
  • - Skype:Bezalel2000
Re: Anybody guess what this is going to be???
« Reply #11 on: June 13, 2013, 07:44:39 AM »
Hi Chuck
 
If you don't mind me asking how did you arrive at the 60-70 turns?
 :thinking:
 
If I do the maths it equates to coil height of 5mm to 5.5mm - it looks a bit bigger than that, maybe
1/4" which should give you about 95 turns (tight wound)
 
N=0.707*H2/d2
 
N= Number of turns
d=diameter of wire #24 = 0.55mm
H=Height of Coil(along the coil axis)
 
Where H=5,     N=60
Where H=5.5   N=70
Where H=6.35 N=95
 
of course there is a tidy factor. If I was winding them myself in a hurry you would have to half all those calculations   :Lol:
 
Bez
Queensland - wet one day, humid the next

Offline Bezalel

  • Full Member
  • ****
  • Posts: 376
  • - Skype:Bezalel2000
Re: Anybody guess what this is going to be???
« Reply #12 on: June 13, 2013, 01:44:13 PM »
Ok I figured out why the difference.
   The  N=√2/2*H2/dassmes the coil is wound onto a regular flat former.  :embarassed:
 
But these formers are concave (same shape as the side of the endmill) so there is no room for windings in the corners at the top and bottom of the coil.   :facepalm:
 
 
I'm looking forward to seeing the real thing in action Chuck,  thanks for inviting us along.
 
Cheers
 
Bez
 
 
 
Queensland - wet one day, humid the next

Offline MuellerNick

  • Full Member
  • ****
  • Posts: 213
  • Germany // Outback of Munich
    • Motor-Manufaktur
Re: Anybody guess what this is going to be???
« Reply #13 on: June 13, 2013, 02:12:13 PM »
Chuck,
do you intend the coils of the stator to be fake and have magnets inside? If not, a coil without (iron; better ferromagnetic) core is quite ineffective. For iron, r is 30010000, for ferrites, it is 415000. So that's the factor your field strength is reduced by not having a core.


Nick

Offline Ian S C

  • Full Member
  • ****
  • Posts: 1065
  • Stirling Engine Maker Darfield Canterbury N Z
Re: Anybody guess what this is going to be???
« Reply #14 on: June 13, 2013, 02:54:32 PM »
I built a little alternator a few weeks ago, it was a little shaded pole motor, 850 rpm type. I took out the armature, and made a new one, it is a 6 finger claw (similar automotive alternator), with 3 ferrite magnets removed from old speakers inside, this will produce about 90V, and gives useful power when fed through a transformer, and a bridge rectifier, to give about 12V.  This alternator was designed for the Stuart S9 .