Author Topic: Anybody guess what this is going to be???  (Read 17748 times)

Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #15 on: June 13, 2013, 03:01:54 PM »
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

Jo, I've been hosting my photos in a public folder of http://www.dropbox.com for some months now. These include the Fairbanks and the radial 3 compressed air.  Are you not able to see pictures from any of my recent posts?  Is anybody else having a problem seeing them?
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Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #16 on: June 13, 2013, 03:12:52 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, µr is 300…10000, for ferrites, it is 4…15000. So that's the factor your field strength is reduced by not having a core.


Nick

After following Manfred Albert's build on HMEM, I decided that non-ferromagnetic coils would be satisfactory for my model.  I know that ferromagnetic cored coils are more efficient and produce more power, particularly as generator size increases, but my little Fairbanks doesn't have much torque and although I'm pretty sure my generator will work, it's more for form than function.  I had spent some time looking at stators used on motorcycle alternators.  They are about the right size and are available used on Ebay for under $30.  I think a decent alternator for a model could be made from one but you'd need a pretty hefty engine to drive it.
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Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #17 on: June 13, 2013, 03:14:59 PM »
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

My estimate is based half on calculation and half on SWAG.  The windings will not be particularly tidy based on having to wind them in place.

Chuck
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Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #18 on: June 13, 2013, 03:20:02 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 .

Yeah, I had looked at using a motor similar to one of these as the basis for an alternator.  They are typically referred to as fan motors.  I think you can also make a pretty decent brushless DC motor from one of these by replacing the armature with one containing permanent magnets.

Chuck
So many projects, so little time...

Offline Jo

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Re: Anybody guess what this is going to be???
« Reply #19 on: June 13, 2013, 03:27:58 PM »

Jo, I've been hosting my photos in a public folder of http://www.dropbox.com for some months now. These include the Fairbanks and the radial 3 compressed air.  Are you not able to see pictures from any of my recent posts?  Is anybody else having a problem seeing them?

Yes I have been having problems for a few months as you say. I thought I would mention it in case anyone else was having similar problems.

I have to remember to get my Linux computer out and access them in a bit of a convoluted way and normally I forget  :-[

Jo
Usus est optimum magister

Offline Ian S C

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Re: Anybody guess what this is going to be???
« Reply #20 on: June 13, 2013, 03:39:28 PM »
Chuck, I wanted to remove the pole shading rings(they are just used for starting these motors), but I would have to remove the main windings, and I'm too lazy to do a rewind, although I could fit in heavier wire, which would be useful in increasing the current, it was a 150 watt motor.     Ian S C

Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #21 on: June 13, 2013, 09:30:23 PM »
OK, Jo, I'll start using Photobucket, just for you, even though it's more trouble...  :stickpoke:

I started work on the outboard stand for the armature today.  I started with a 1" x 1.25" x 3" piece of aluminum.  In this first picture I've drilled the pilot hole for the armature shaft and went all the way around the base with a 1/4" ball nose end mill.



Here I'm using an end mill and my rotary table to start shaping the front and back.



Finished rough cutting the front (or back :-\).



And here's a couple of pictures after all the shaping and filing is done. 



The finish, such as it is, was made with my random orbital sander.



OK, Jo, you're off the hook.  Turned out not to be as much trouble as it used to be and now I get to save space on my Dropbox account for other things!
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Offline Jo

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Re: Anybody guess what this is going to be???
« Reply #22 on: June 14, 2013, 07:36:59 AM »
Brilliant I can see them  :whoohoo:

Following along  8)

Jo
Usus est optimum magister

Offline Bezalel

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Re: Anybody guess what this is going to be???
« Reply #23 on: June 14, 2013, 03:23:43 PM »
Hi Chuck
 
I don't think you'll have much trouble making enough juice to drive a couple of Doz White LEDs at about 60mW each.
 
I guess we'll get to see eventually but some of us are impatient mugs..  ;D    so I'll ask now
 
What will you be using for your induction source?
 
and how will they be configured? by that I mean; with the eight windings were you aiming to get 60Hz at 900rpm?
 
There is just so many ways you could set this up.
 
Oh! By the way... if these questions are gettig in the way of building this thing... just skip the answers & go streight to the workshop so you can get more progress photos.
 
    :ThumbsUp: :ThumbsUp: :ThumbsUp:
 
Bez
 
 
Queensland - wet one day, humid the next

Offline Noitoen

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Re: Anybody guess what this is going to be???
« Reply #24 on: June 14, 2013, 09:16:01 PM »
Chuck, I wanted to remove the pole shading rings(they are just used for starting these motors), but I would have to remove the main windings, and I'm too lazy to do a rewind, although I could fit in heavier wire, which would be useful in increasing the current, it was a 150 watt motor.     Ian S C

You don't have to remove the shading rings, just cut them open. Is the motor you using a 6 pole one. The stator should have the same number of poles than the rotor.

Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #25 on: June 14, 2013, 09:40:23 PM »
Hi Chuck
 
I don't think you'll have much trouble making enough juice to drive a couple of Doz White LEDs at about 60mW each.
 
I guess we'll get to see eventually but some of us are impatient mugs..  ;D    so I'll ask now
 
What will you be using for your induction source?
 
and how will they be configured? by that I mean; with the eight windings were you aiming to get 60Hz at 900rpm?
 
There is just so many ways you could set this up.
 
Oh! By the way... if these questions are gettig in the way of building this thing... just skip the answers & go streight to the workshop so you can get more progress photos.
 
    :ThumbsUp: :ThumbsUp: :ThumbsUp:
 
Bez

Not sure what you mean by induction source.  The armature will have 16 bar magnets arranged with alternating N & S poles facing outward.  The coils will all be hooked in series.  This will allow all the south poles to pass the coils at once followed by all the north poles passing the coils at once.

Chuck
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Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #26 on: June 14, 2013, 09:45:58 PM »
Got the stator frame and outboard armature support mounted on a common base.  Next I'll start on the armature and armature shaft.  I need to order the magnets.  I'll need 16, 1" x 3/8" x 1/8" bar magnets with the poles on the large flat face. Or I could use 1" x 1/4" x 1/4 with the poles on the long sides.  This would allow a bit more space between the magnets. 







I want to get the armature assembly finished before I start winding the coils so I can experiment a little with different numbers of turns in the coils.

Chuck
So many projects, so little time...

Offline Bezalel

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Re: Anybody guess what this is going to be???
« Reply #27 on: June 15, 2013, 10:08:32 AM »
Nice progress Chuck  :ThumbsUp:
 
Not sure what you mean by induction source.  The armature will have 16 bar magnets arranged with alternating N & S poles facing outward.  The coils will all be hooked in series.  This will allow all the south poles to pass the coils at once followed by all the north poles passing the coils at once.

Chuck

Thanks. You have answered the question.
 
That should produce even more current and higher frequency per revolution than the very simple eight magnet version I was imagining.
 
Just to verify you correctly picked up what I meant by induction source, I meant the source of magnetic flux which when moving relative to stator coils will induce the EMF in the coil windings.
 
I thought it was easier than asking; permanent magnet? or wire wound? and if wire wound how is the initial excitation established? 
 
Cheers
Queensland - wet one day, humid the next

Offline Ian S C

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Re: Anybody guess what this is going to be???
« Reply #28 on: June 15, 2013, 02:22:35 PM »
Noitoen, the stator is 6 pole.  The shading loops are too buried to get at, but we'll see what happens.  I have done a similar modification to a larger induction motor.  Ian S C

Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #29 on: June 24, 2013, 11:27:46 PM »
I received my magnets from KJMagnetics and installed 8 of them on my armature.  I've done a bit of testing and results are a bit disappointing, but I think I will be able to get it where I want it.  Here's a picture with the armature withdrawn for illustrative purposes.



I've installed 8 magnets and have 200 turns of #27 wire on one pole of the stator.  Turning the armature at somewhere around 1500 RPM's and feeding the output through a full wave rectifier gives me .25 volts.  Multiplied by 8 would give me 2 volts.   That's probably enough to light an LED but if I add another 8 magnets, I'm thinking I'll get 4 volts and if I add 16 magnets I should get 6 volts.  Since the #27 wire is rated at .287 amps, I'm guessing an incandescent lamp is out of the question.

Chuck
So many projects, so little time...