Author Topic: The dynamo and the tu-tu  (Read 31115 times)

Offline zeeprogrammer

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Re: The dynamo and the tu-tu
« Reply #60 on: February 13, 2014, 10:02:06 PM »
Why hi there Pete. It has indeed been a long time. Have you been active on the forum and I've just been bad about finding you?

Great idea. I'll take a run at that before springing for new parts.

Eric...both bearings are thru. But I think Pete may have come up with a recipe for casserole.

Thanks all!
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline zeeprogrammer

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Re: The dynamo and the tu-tu
« Reply #61 on: February 13, 2014, 10:43:55 PM »
That did the trick Pete. Thanks again.

So Marv will have to wait a little longer. We'll see who says 'crap'.

Probably done for the day. After 5+ hours working in the snow, I'm beat. We're supposed to get more tonight.

And yes...the armature turns. Fairly easy with a tap wrench. Not so easy with oily fingers.
Still have to try the magnets and see if the armature is centered.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline Don1966

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Re: The dynamo and the tu-tu
« Reply #62 on: February 14, 2014, 12:20:30 AM »
 :ThumbsUp:

 :zap:

Don

Offline b.lindsey

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Re: The dynamo and the tu-tu
« Reply #63 on: February 14, 2014, 12:27:42 AM »
I think you can put together a successful casserole there Zee. Its been so long since I did mine I can't offer any suggestions but it certainly looks fixable. Worst case, get two new bells from PRM and try again. Keep after it.

Bill
« Last Edit: February 14, 2014, 01:47:14 AM by b.lindsey »

Offline zeeprogrammer

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Re: The dynamo and the tu-tu
« Reply #64 on: February 14, 2014, 01:13:47 AM »
Thanks Don and Bill.

I either go to bed and not sleep thinking about this...or I stay up not sleeping and do some more...
I opted for the latter.

Made the spacer for the magnets. Simple disk with a 3-48 through.
Then a dummy eye-bolt.
Spot faced and drilled the frame.
Put it together.

Video...



Not sure if the video will work. I'm having issues with this computer. Internet is molasses.
Tried the Mac but for whatever reason all plug-ins are disabled and is preventing the videos from showing.
Haven't figured my way out of that one yet.

No binding. Seems to be just fine.

Guess I'm lucky.  ;D

Now I can sleep.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
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Offline b.lindsey

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Re: The dynamo and the tu-tu
« Reply #65 on: February 14, 2014, 01:52:57 AM »
Looks like you got it licked Carl. I am curious as to how you separated the magnets though. I was thinking there were some leaf springs that kept the magnets apart at the top and bottom, but I can't look at mine at the moment and my memory may not be that clear. I think I got this kit when they first came out which was a while back.

Bill

Offline zeeprogrammer

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Re: The dynamo and the tu-tu
« Reply #66 on: February 14, 2014, 03:42:04 AM »
Hi Bill,

The top separation is done by an aluminum disk. Threaded thru 3-48 that the eye-bolt connects to.
And yes, you are right, the bottom separation is done by a little leaf spring.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
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Offline doubletop

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Re: The dynamo and the tu-tu
« Reply #67 on: February 14, 2014, 05:02:13 AM »
Zee

I think my last postings here was my loco refurbishment  I've made a couple of 4 stroke engines since but didn't do much of a build log as they were from the UK model engineer magazine and the articles were way better than I could have supplied. I did a few mods to the design that I posted on the ME website. Which of course meant you guys in the USA missed out I'm afraid.

Back to your generator: is it supposed to be that tight, or is something fouling? How does the armature spin in the housing without the magnets installed? If it isn't free you could try fitting the end bells in different orientations until you found one that was best. And then mark it!. If that doesn't work fit the end bells with no armature and if you've got a long enough reamer ream the  bearings through end to end. And again mark the position of the end bells!!

Pete
?To achieve anything in this game, you must be prepared to dabble on the boundary of disaster.? - Stirling Moss

Offline zeeprogrammer

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Re: The dynamo and the tu-tu
« Reply #68 on: February 14, 2014, 10:34:00 AM »
Glad to hear you've been busy Pete. Any thoughts for a build log here? And don't worry about articles. No doubt you would be able to add tips-n-techniques to them.

I don't think anything is fouling. The shaft turns smoothly with no indication of a bind spot.
However, I have no idea how easy it should turn. And one bell is certainly a tad tight even when I turn it on the shaft without the frame. A little more reaming may be in order. I suppose it's possible the bushings are not quite true but I can't tell much difference whether in the frame or just spinning the bells on the armature without the frame.

I don't know much about bushings. Is a light oil called for?

So that's the question for those of you who have built these. If I give the tap wrench a flip...how much should it turn?
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
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Offline Ian S C

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Re: The dynamo and the tu-tu
« Reply #69 on: February 14, 2014, 12:19:31 PM »
You said earler that one bearing bush was a bit tight in its hole,  what type of bush are they, Oilite, these are manufactured to finished size, and require an accurate size hole to close the bush to its correct size, it must not be reamed, as this spoils the self lubricating  function of the sintered bronze.  If they are brass or bronze plain bearings, make a tool makers reamer from a bit of steel the same diameter as the shaft, and long enough to go through both bearings, sharpen it on a oil stone, but leave the very slight burr on the edge, going through the looser bearing it may not remove any metal, and just a whisker from the tight one.  You should not need to harden the reamer, unless you have cast iron bushes.  Plain bearings, use a light oil/sewing machine.  Oilite bushes come(usually) pre oiled, but you can charge them with oil, hold it with the hole vertical, put your finger under it, fill with oil, put your thumb on top and squeeze, on your dynamo it can be done in situ.  Ian S C

Offline Alan Haisley

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Re: The dynamo and the tu-tu
« Reply #70 on: February 14, 2014, 03:36:43 PM »
If I give the tap wrench a flip...how much should it turn?

Without the magnets in place it should free-wheel "a bunch". Meaning that if you only get a revolution or two something is too tight but if you get five or six (or eight or ten) it should be really good. The more it is willing to free-wheel, the better so long as there is no shake or rattle along with the roll.

Alan
Near Raleigh, NC, USA

Offline zeeprogrammer

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Re: The dynamo and the tu-tu
« Reply #71 on: February 14, 2014, 07:41:23 PM »
Ian...
Not sure what kind of bearing. The BOM simply says bearing. I don't think brass. Bronze perhaps...but I don't have enough experience with any bearings to know the difference yet.

You mention 'accurate holes to close the bush to correct size'. The only way I can see the bush coming to size is if it simply crushes. Given this is an inexpensive kit...I suspect it's not Olite.

Alan...
Pretty much got the same without the magnets. Took it apart and the bell seems to spin pretty freely. So it seems somethings is not true.

Per Pete's suggestion I tried different bell positions. There was a noticeable improvement when turned 180 degree. With that I also applied a tad of light oil. More improvement.

Still though, it spins just a few revs easily. Maybe 4 or 5.

I'm thinking good enough but I'm wondering if the problem is the other bushing. One thing I noticed is some aluminum 'flash' along part of the perimeter of the bushing. I'm wondering if it really pressed straight and true. No arbor and the drill press table tilted some as I pushed.

In any case...

I need not give a direct invitation to Marv. He knows I am always ready for education whether pre- or post- boo-boo.  ;D

Thanks for everyone's help and input. I have gained from it.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline zeeprogrammer

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Re: The dynamo and the tu-tu
« Reply #72 on: February 15, 2014, 12:31:09 PM »
If the bore of the frame is not true then wouldn't one bell's center sit off from the other?
The center of the armature at one end would differ from the other, no?
I wouldn't be surprised. I've always had problems with that.
I have some ideas to prove that out. All may not be lost.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline Ian S C

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Re: The dynamo and the tu-tu
« Reply #73 on: February 15, 2014, 01:01:57 PM »
Zee, the Oilite bushes are quite cheap, mainly I suppose because of bulk manufacture, they are preformed, and just need insertion into a hole that will close them to there designed size.  You can identify them by the oily feeling of them, the metal is porous, and retains the oil within it.  Most small electric motors have these bearings, some times they are spherical, and self allining, often with a felt pad with extra oil.     Ian S C

Offline zeeprogrammer

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Re: The dynamo and the tu-tu
« Reply #74 on: February 15, 2014, 01:45:14 PM »
Thanks Ian.

I took it apart and inserted a punch to see if I could discern anything.
Seemed okay but granted...using a punch probably wouldn't help.
Then I started putting it back together.
One bell bolted on.
I held the other bell by hand...things spun freely.
One bolt on. Freely turns.
Second bolt on. Freely turns.
Third bolt on. Aha.
I suspect I may have bent the thing ever so slightly (but enough) when I pressed the bushing.

Overall then I'm pleased. It's good enough to work and I learned  few things.

Marv...you needn't keep your mouth zipped.  ;D Let it out.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.