Rebuilding a homebrew coil winder
With a 450W motor and low gearing and plenty of space around the mandril it should be able to do a 500 VA transformer easily.
I plug it into my Variac for soft starting with fine wire but with heavy stuff the built in speed control is fine.
The internal speed control sounds like an Indian taxi at very low speed and can snap fine wire.
The control board is completed, baring something unforeseen.
Its a bit all over the place as it has evolved with the project. The control board, the LCD and key pad will sit in an enclosure on the right hand side of the Transverse. There wasn't enough room to house the power supply so it will be in an enclosure for itself to the rear of the winder.
I have added extra decoupling cap's to the control board to keep the reg's happy.
The first line of the display is the turns wound.
The second line is the Wire diameter in um.
The third line is winding speed and any errors that has occurred while winding.
The fourth line is the width of the coil being wound and the direction of travel of the carriage.
It is looking very good.
How does it count the turns - Is it counting "real" turns or just the calibrated pulses that drive the motor?
It is counting real turns, there is a magnet on the chuck that operates a reed switch each time the chuck turns once. The turns counter increases by one and the carriage moves by one wire diameter. Through the menu, the required amount of turns can be set, the winder will slowdown as this number is reached and stop at it.
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.
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!).
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.
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.
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.
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.
One picture says a thousand words and one video pretty much explains it all. Nice job Frank.
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.
... 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
When all else fails, read the instructions
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.
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.
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.