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Rebuilding a homebrew coil winder

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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Wed Oct 08, 2014 11:07 pm

Thanks Brian
PIC's are marvelous devises in some situations. I am really learning, making loads of mistakes and doing daft things along the way.
If I can muddle my way through, there is absolutely no doubt in my mind that you would be well able to master these devices should you desire.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by Brianc » Thu Oct 09, 2014 10:44 am

While I was still at work, I bought a few of the educational kits that Farnell were doing at the time thinking they would be a good start. However, I needed to go back further than the point in the technology from which the kits started. Three books later, I still couldn't get a real grasp of the basics so I gave up. I am, after all, from an all valve analogue environment where the word "software" hadn't even been coined.
So I'll stick with me old teles, I think. (he said defeatedly!). :aab :aab

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Thu Oct 09, 2014 9:08 pm

Hi Brian
sometimes those educational kits go far too deep into things and what you really need to know gets lost.

I was going to uploaded a pdf of the diagram not realizing that I couldn't.
I have took a screen grab of it and uploaded that.

Frank
Attachments
dia.gif

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Fri Oct 10, 2014 8:52 pm

Over tension and main brake switches added, they will be activated by the jockey pulley arm.

Frank
Attachments
supply reel 3.jpg
ot and mb switches.jpg

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Sat Oct 11, 2014 10:27 pm

There was a small bit of lateral movement of the carriage, it was pivoting around the coupling to the lead screw. I have fitted two extra linear bearings, there are a total of four now.
This has totally got rid of any movement, it is rock steady now.

The Transverse wont be fastened directly to the base board. Instead there will be two panels one each side of the transverse that will be fastened to the base board. these panels has a slot cut in them, a traded rod goes through the transverse and the slots, wing nuts tightens the lot together. This will allow the transverse to be positioned to suit different sized coils being wound.

Frank
Attachments
transverse 6.jpg
transverse 7.jpg

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Wed Oct 15, 2014 11:13 pm

I have mounted the control board and power supply into their enclosures.

I have included a socket on the power supply for the take-up unit to plug into.

I have used a random assortment of connectors on the control unit.
A 1/4" stereo jack supplies the PWM to the take-up unit and receives the pules from the chuck's reed switch.
A 9pin D connector is for the power supply, the main brake switch and the over tension switch.
The stepper motor connects via 6 pin connector and a piece of 0.1" header epoxied into the case is for the ICSP.

Frank
Attachments
POWER SUPPLY.jpg
CONTROL BOARD 2.jpg
CONTROL BOARD 3.jpg

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Sat Oct 18, 2014 11:05 pm

Today I finally got everything put together so it could be tested.
This is a link to a video clip of one of the first tests that I have done on it. I have no coils to wind so I used a 19mm spade bit. I used the bit because it would draw the wire at an irregular speed so to test the function of the jockey pulley. I am winding 200 turns of 0.125mm wire with a coil width of 10.1mm.
The winder slows down at about 50 turns from the end of the coil.

It's almost there now I just have some of the code to finish off, I needed to have it running before I could finish it.

Frank
Attachments
CONTROL UNIT.jpg
COIL WINDER.jpg

 
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Re: Rebuilding a homebrew coil winder

Post by valvekits » Sun Oct 19, 2014 4:44 pm

One picture says a thousand words and one video pretty much explains it all. Nice job Frank.

Eddie

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Sun Oct 19, 2014 6:53 pm

Thanks Eddie.
Another advantage of a video is it made me give the bench a badly needed clean up.

I should have embedded the video in the last post, I will in this one.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by Terrykc » Sun Oct 19, 2014 7:22 pm

FRANK.C wrote:... I was going to uploaded a pdf of the diagram not realizing that I couldn't.
I have took a screen grab of it and uploaded that ...

Creating a diagram like that as a .png or converting the pdf* to .png can produce largish clear diagrams well within the 120k limit.

* You can use Print Screen for this - then load into Paint (or something similar) to crop down to size, then save as a .png file.

Windows 7 and up include a Snipping Tool, which makes things even simpler and the snipped image can be saved straight to a .png file

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Mon Oct 20, 2014 1:15 pm

Hi Terry
Good tip, that's basically what I did except I saved it as gif.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Mon Oct 20, 2014 9:15 pm

Just for completeness the circuit of the Take-up unit in png.

Frank
Attachments
Take-up Dia.png

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Wed Oct 22, 2014 8:45 pm

I have attached a new video. there is not much new in it. This time it is 200 turns of 0.05mm wire that is been wound, that is the thinnest that I have.
I have narrowed the coil width to almost 5mm (the coil width is calculated as the distance the carriage travels plus one wire width). The back tension and jockey arm tension have been adjusted to suit the 0.05mm wire. The wire diameter is set to 64um to allow for the insulation.

Frank


 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Thu Oct 23, 2014 10:54 pm

The PIC monitors some switches etc and if everything isn't as it expects, it will either make a change to the wining speed or will stop winding. When it dose it displays an error code to indicate why it took action.

The user can change the speed of winding at any time but if the PIC detects that the carriage is not able to keep up with the take-up (this will only happen while trying to wind larger diameter wire at higher speeds) the PIC will take over control of the speed and reduce it to a level where the carriage can keep up. The PIC then sets this speed as the maximum. From then on the user can decrease the speed below this set maximum but can not increase it above it. Error "1" will be displayed to indicate why the speed was reduced. The maximum speed can be reset via the menu.

At switch off or when power is lost all relevant variables are saved so that at switch on or when power is restored it starts exactly where it left off. If the take-up is active when power is lost, when power is then restored it starts up exactly where it stopped at, except the take-up is stopped and the start button has to be pressed to restart it. When power is restored after power been lost while the take-up is active, error "2" is displayed, otherwise it may not be obvious why the winder stopped.

If the main brake switch is activated while the take-up is active, the take-up is stopped and error "3" is displayed.

If the over tension switch is activated while the take-up is active, the take-up is stopped and error "4" is displayed

If no pulses are received from the reed switch while the take-up is active, the take-up is stopped and error "5" is displayed

As it stands now if winding using the hand cranked take-up, errors 1,3,4 and 5 will be displayed but obviously have no effect. I may yet include a "Manual" setting in the menu to stop these errors from being displayed. The "Ready" led on the control panel is off while the carriage is moving. While winding manually this led should be flashing, if it is off all the time this indicates that the user is winding too fast and the carriage cant keep up.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by pclover » Sun Oct 26, 2014 9:44 am

Hello Frank

Most interesting and very clever me thinks. It will be good to see some multi-layer coils wound with it although the test drill windings look promising. Layer winding isn't easy (depends a lot on the wire gauge) and normally interleaving paper has to be used between layers. I have never bothered to do that and simply 'scramble' wound which works fine for many coils particularly with modern wire with 1000V insulation even if it slips down a few layers.

Your winder is sophisticated, mine was crude using a drill motor but I did make it have foot pedal control. Wire guidance was by hand using a support tube.

Its a while ago now and was written up as a BVWS article (later another BVWS member made a more refined version of it) and I wonder if you could do an article for yours? The BVWS Bulletin is always short of good copy and yours would be good as its the most ambitious home built winder I have seen to date.

Even if you are not a BVWS member the Editor will happily accept copy but of course I urge you to become a member.

You seem to have all the photographs done and a lot of the words so please consider it.

thanks Gary

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Sun Oct 26, 2014 3:23 pm

Hi Gary
Thanks for your comments. I have never done layer winding with paper between layers any transformers that I have to rewind if they haven't already got cheeks I fit some and wind between them, it makes life a lot easier and as you say with modern wire there is really no need for the paper.

I would have liked to have seen your article, it sounds very interesting. I am just 2 years a member of the BVWS so I guess your article was before that.

The Bulletin is a great publication with well written articles, one I always look forward to receiving . I would like to support it by writing an article for it but I'm afraid my writing skills are not very good.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by pclover » Mon Oct 27, 2014 9:49 am

Hello Frank

Well if you make the time to do an article the Editor and the Proof readers are normally happy to knock it into shape if your writing skills are below par. Reading your input on here though I don't see much of a problem. BTW it is a way of improving them and engineers need to express themselves on paper. I'm glad you are a member of the BVWS and hope you enjoy it. One of the best things about it is the beautifully prepared Bulletin but without quality (interesting, not done before etc) copy it can never be absorbing.

As to not seeing my articles, well you don't want to. Mine was just a crude effort but has wound field coils and transformers and got me out of trouble in restorations. I don't have the mechanical skills that you have and neither the PIC experience. I always say that I want to have a go at it but a radio comes my way and another restoration gets started. The cheap development board is amazing value and I used to be a pretty good Basic programmer so one day maybe ...

Yes! I agree on not needing paper for insulation but I believe it was often put in (by nimble fingered ladies) so that the next layer would wind smoothly.

A friend, who is not a member but with an interest in coil winders, commented:
It does not address the issue of being able to traverse smoothly back and forth without stopping the winder at the end of each layer. He was also surprised at the amount of movement of the rear jockey wheel and watching the video again so am I. Perhaps it is because the wire does not come off the feed reel smoothly ?

I appreciated that this is an on-going development but it would be good to see, in conclusion, it wind a multi layer coil. It wouldn't be hard to knock up a bobbin with end cheeks * and make a dummy coil with a challenging wire gauge (how about around 40 SWG).

Often coils were wound without end cheeks because of the wire feed snagging the cheeks which are bound to run a little out of true. Of course a way around this would be not to wind right up to the cheeks and let succeeding layers eventually spill over to it. A method without cheeks was to wind a layer and then apply a glue to the ends. It must have been very quick setting or perhaps they had a heater blowing hot air to assist drying.

Winding without cheeks allowed another possibility and that was winding more than one coil on the former tube and cutting them to make individual coils when it was de-mounted.

Good stuff and well done Gary

 
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Re: Rebuilding a homebrew coil winder

Post by Brianc » Mon Oct 27, 2014 11:26 am

Exceptional work, Frank.
The movement of the jocky wheel Gary mentions could be down to the brake you have on the feed reel. Maybe polish the "drum" a little more and add some fine oil. Player pianos use a similar way to steady the feed spool and they need to be oiled with sewing machine oil fairly often. Also perhaps a softening of the "pad" material would help!
Nevertheless, a fantastic project - you must be proud of what you have achieved. :aap :aap

 
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Re: Rebuilding a homebrew coil winder

Post by Refugee » Mon Oct 27, 2014 1:02 pm

The jockey movement looks to me like there is a sticky label on the cheek of the supply spool.
I am building a slightly more crude winder and it has a wheel bearing that was salvaged from a broken micro scooter under the supply spool with a manual brake formed by adding sideways pressure to the bearing.

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Mon Oct 27, 2014 3:13 pm

Hi Trevor
Yes time is the most difficult part to find enough of for a project

Hi Gary
I will contact the Editor and see what he says.

"A friend, who is not a member but with an interest in coil winders, commented:
It does not address the issue of being able to traverse smoothly back and forth without stopping the winder at the end of each layer. "
I am probably been dense but I don't understand this comment?

I have some 40 SWG wire, I used it in the first clip. I have not wound a multi layer coil before but when I get a chance I will try one, it will require the program to be changed a little to stop winding when each end of the coil is reached to allow the paper to be inserted. How any layers? What type of paper between layers, Baking paper?

H Brian
You are correct as to why the jockey pulley is moving so much at slow speeds. The brake wheel is slightly off center, it could do with being put in a lathe to out but I have none. I may try doing it with a drill.

Hi Refugee
Your winder sounds interesting any chance of starting a thread.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by Refugee » Mon Oct 27, 2014 4:56 pm

I started building it ages ago and it has been on and off the to do pile for about 3 years. It has just been back again this summer for the micro scooter bearings to be fitted after I found a broken one fly-tipped and salvaged the parts.
viewtopic.php?t=2602&p=26538#p26538
The stuff you put between the layers is oil based.
This should at least give you the search term for you to add the coil former width to.
http://www.ebay.co.uk/itm/HIGH-TEMPRATU ... 258f60794e

I am pretty sure that coils without tape or paper were wound with something sticky on the wire added by a brush either by the jockey wheel or onto the bobbin while a pair of cheeks were pushed up to to the ends of the coil former. Then the cheeks of the bobbin would be built on later.

 
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Re: Rebuilding a homebrew coil winder

Post by pclover » Mon Oct 27, 2014 7:23 pm

Hello Frank

"A friend, who is not a member but with an interest in coil winders, commented:
It does not address the issue of being able to traverse smoothly back and forth without stopping the winder at the end of each layer. "

"I am probably been dense but I don't understand this comment?"

Well as I understand it the videos and text only show winding a single layer. The hard part is getting it to slow, stop and than reverse for other layers. So winding a multi layer coil is the challenge !

You don't need interleaving paper with modern high insulation wire so it would be suck it and see how the winder copes with the less than smooth surface of the previous layer. I have a link, somewhere, for the paper but as I say this is really cosmetic. Yes! we all like to see a coil wound with side by side by turns, layer after layer but it wont work any better.

The Editor will jump at the chance of an article.

Gary

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Mon Oct 27, 2014 9:12 pm

Hi Refugee
Thanks for the links.
That tape is reasonably priced.

Hi Gary
I understand now. I haven't made things as clear as I should have. The coils on the clips are multi layer.

At the start of the first clip you will see on the display. that the wire diameter is set to 144um this allows for the insulation as I am using 125um (40SWG) wire. You will also see that the coil width is set to 10.1mm and I have set the turns required (which cant be seen) to 200, so 200 * 144um = 28.8mm so that coil will have 2.8 layers.

In the second clip the wire diameter is set to 64um (0.05mm wire been wound) and the coil width is set to 4.99mm again 200 turns are been wound the coil will have 2.5 layers.

In the clips the transverse is moving so slowly and the camera is moving all the time, it is imposable to say from the clip which direction the carriage is moving. In the first clip I held the camera on the coil until the transverse change direction but watching the clip back it cant be seen that the direction has changed.

At what point's the carriage changes direction is set through the menu. In the menu "carriage setup" is selected . The carriage is moved to the left side of the coil using the "MOVE LEFT" and "MOVE RIGHT" buttons on the control panel, the "SET LT. STOP" button is pressed, this sets the point that the carriage changes direction from left to right.
The carriage is then moved to the right side of the coil and the "SET RT. STOP" button is pressed, this sets the point where the carriage changes direction from right to left. The width of the coil is also calculated and displayed on the bottom line of the display. The left stop and right stop can be changed at any time during winding via the menu. While in "carriage setup" the "FIND LEFT" and "FIND RIGHT" buttons moves the carriage to the left or right stop to aid changing the stops after they have already been setup. When exiting "carriage setup" if the carriage is outside the set bounds of the coil the controller will move it to the nearest end of the coil. The controller just counts the number of steps the stepper motor takes to keep track of where the carriage is at, there is no need for any switches.

I hope that makes things a little clearer.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by pclover » Tue Oct 28, 2014 11:27 am

Thanks for the clarification Frank.

I really hope you do an article. A good tip, from someone who has done plenty, is to get a fellow enthusiast to proof read it before you submit it. Often stuff I write is clear to me but not to someone else.

cheers Gary

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Sun Nov 02, 2014 1:55 am

I have centered the brake wheel by putting the supply shaft (bearing end) in the in a pillar drill and and grinding the brake wheel down while it was spinning.

The top pulley on the carriage was wobbling slightly so I have swapped it for a "V" groove bearing.

I have wound a test coil of 500 turns, this time on a former from a small mains transformer. I wound it with the hand cranked Take-up.
To take the video clip I fastened my phone to the bench Anglepoise to keep it steady, it is easier to see the movement of the carriage in this clip.
The large movements of the jockey arm are mainly due to me not keeping a constant speed as I wound.

Frank

Attachments
winder hc1.jpg
Test coil 2.jpg

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