Author Topic: Anybody guess what this is going to be???  (Read 17834 times)

Offline Bezalel

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Re: Anybody guess what this is going to be???
« Reply #30 on: June 25, 2013, 12:47:24 AM »
Hi Chuck
 
If you skip the bridge rectifier you should be able pick up a bit of voltage.
 
Just wire your LEDs in pairs back to back with a series current limiter.
 
or set the LEDs in a bridge configuation themselves.   ;)
 
Bez
 
 
Queensland - wet one day, humid the next

Offline MuellerNick

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Re: Anybody guess what this is going to be???
« Reply #31 on: June 25, 2013, 08:05:09 AM »
Quote
Just wire your LEDs in pairs back to back with a series current limiter.


I think you mean to wire them anti-parallel. But LEDs will mostly fail at a reverse voltage above 5 V!
Chuck, I hope the magnets are properly oriented, you can get them in (at least) two orientations.


Nick

Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #32 on: June 25, 2013, 06:07:26 PM »
Quote
Just wire your LEDs in pairs back to back with a series current limiter.

I think you mean to wire them anti-parallel. But LEDs will mostly fail at a reverse voltage above 5 V!
Chuck, I hope the magnets are properly oriented, you can get them in (at least) two orientations.

Nick

I double checked the magnet orientation and they are all in correctly, alternating poles facing out.  I've ordered some more magnets, but will do some further testing in the meantime. 

Chuck
So many projects, so little time...

Offline Don1966

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Re: Anybody guess what this is going to be???
« Reply #33 on: June 25, 2013, 06:14:25 PM »
Hi Chuck, the magnets you are using and this is just a question. When you purchased the magnets, did they specify that the north and south poles were end to end or front to back?

Don

Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #34 on: June 25, 2013, 08:23:38 PM »
Hi Chuck, the magnets you are using and this is just a question. When you purchased the magnets, did they specify that the north and south poles were end to end or front to back?

Don

The poles are on the large flat faces...

Chuck
So many projects, so little time...

Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #35 on: June 25, 2013, 10:45:09 PM »
So I removed the single winding and then wound all eight stator coils, 200 turns each with alternating coils wound in the opposite direction.  Boy, glad I don't have do that 8 hours a day to pay the rent.  That is mind numbing work!



I also epoxied another row of magnets on the armature.  I broke one in the process, so I'll need to await my order to install the last magnet.  As an aside, I discovered that JB weld does indeed have some kind of magnetic material in it.  Don't know if its steel, iron, cobalt or what, but the gooey mix is most definitely attracted to the magnets.

Chuck
So many projects, so little time...

Offline Bezalel

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Re: Anybody guess what this is going to be???
« Reply #36 on: June 27, 2013, 09:20:32 AM »
Looking good Chuck
 
 
 Nick
 
Please tell me you're not saying anti-paralled LEDs will fail due to the reverse voltage?  Silliest thing I ever heard.  :lolb:
 
We both know the reverse bias voltage on one diode of the pair can never exceed the forward bias voltage of the other.  :happyreader:
 
Quote
Just wire your LEDs in pairs back to back with a series current limiter.


I think you mean to wire them anti-parallel. But LEDs will mostly fail at a reverse voltage above 5 V!
Chuck, I hope the magnets are properly oriented, you can get them in (at least) two orientations.


Nick

 
Queensland - wet one day, humid the next

Offline MuellerNick

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Re: Anybody guess what this is going to be???
« Reply #37 on: June 27, 2013, 09:51:33 AM »
Quote
We both know the reverse bias voltage on one diode of the pair can never exceed the forward bias voltage of the other.   


I stand corrected!  :embarassed:


Nick

Offline Alan Haisley

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Re: Anybody guess what this is going to be???
« Reply #38 on: June 27, 2013, 06:16:15 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. 

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
After looking at your picture and at the K&J catalog, I think that you can use thicker magnets. Based on their specifications that would let you apply a higher Gauss field which might help. You may also be able to double them up. Another thought is to mount them slightly skewed or with NS in line with the armature chords.
It looks like you have a lot of orientation choices here that may change the output. At a slower speed you may be able to clamp the magnets with wire bands or something so that you can reuse them with a bunch of armature configurations and orientations without having to spend a fortune for magnets.
Alan
Near Raleigh, NC, USA

Offline Don1966

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Re: Anybody guess what this is going to be???
« Reply #39 on: June 28, 2013, 12:58:13 AM »
I agree that the magnets need to be bigger as Alan has said, but also the magnet should be the same width as the pole piece for good magnet flux coverage.

Just my 2c

Don

Offline Noitoen

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Re: Anybody guess what this is going to be???
« Reply #40 on: June 28, 2013, 01:27:56 PM »
it's very important that the polarity of the bar magnets, in your case be "top to bottom" and not like those old school magnets that where painted half red and blue along the length.

As for the size, if the polarity is right, some round segments of soft steel can be glued to the magnets to widen the magnetic field. the flux density on those neodymium magnets is much denser than the increased area of the little inserts are able to carry without saturating.

Offline cfellows

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Re: Anybody guess what this is going to be???
« Reply #41 on: June 28, 2013, 03:11:44 PM »
I'm still waiting for my second order of magnets to arrive.  I did do a trial run with the magnets doubled up, except for the one I broke.  I measured about 3.6 volts AC at around 1500 RPM and about 3.4 volts DC when I hooked up the full wave rectifier.

I was able to light a large LED with the full wave DC, but when I took out the rectifier, it wouldn't light with straight AC. 

Chuck
So many projects, so little time...

Offline Stuart

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Re: Anybody guess what this is going to be???
« Reply #42 on: June 28, 2013, 04:14:38 PM »
a LED is a diode and therefore conducts one way some are back to back and will work either way sometimes for tow colour operation

you need DC for a LED at least you did when I was into electronics used to be G4IJX and built an early computer zilog Z80 based



but as usual i may be wrong
BTW yes it is mind numbing try a two pole High frequency stator for  a grinder 1 3/4 bore and three inches long there is not much room to do the winding on those

Stuart
My aim is for a accurate part with a good finish

Offline steamer

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Re: Anybody guess what this is going to be???
« Reply #43 on: June 28, 2013, 06:40:22 PM »
Nice progress Chuck!... I really like the genset!....it's a nice thing to do with our small engines for shows and stuff....and it looks the part.

Glad we are all sorting out the electronics.....

Dave
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Damned ijjit!

Offline Noitoen

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Re: Anybody guess what this is going to be???
« Reply #44 on: June 28, 2013, 10:42:49 PM »
I think there must be something wrong. I've worked for many years with motors and alternators and although they had a core, self exited alternators generate at least more than 3 volts when they are rotated at 1500 rpm with just the core's residual magnetic field and with few turns on their coils. Only when the regulator, using this voltage "wakes up", does the magnetic field grow to the get the full voltage. Neodymium magnets are so strong the leads me to believe you should double check your system.