[Ken Stuempge]

Sorry, the wire spool photos are here:

[BillTodd]

Consider the area to be filled a rectangle, with the center of the bobbin at the bottom and the ends of the bobbin at the left and right.

Then lay down two turns starting at the left edge. The wind backwards diagonally to lay down another turn nestled between those two (but higher). Now go diagonally back and forth laying down turns in a triangular pattern until you have the requisite coil diameter.

Then continue diagonally back and forth increasing the length of the coil until you are at the end. Finish up by filling int the triangle on the right.

This pattern will have the characteristics that the voltage between turns that are near another is small. The two ends at the maximum voltage difference will be far apart.

Does my description make sense? Will this work?

Ken

Interesting idea.

I found this gas hob ignitor pcb in the garage (see pic).

Each ignitor has the secondary (UHT) winding split across four small bobbins, presumably to spread the voltage tension and prevent flash-over. There are four UHT outputs sharing a single primary.

The HV cap discharge circuit is interesting; There is an extremely high value resistor (>100Mohms) on the end of each secondary connected to a few hundred volts dc. This resistor normally charges a timing capacitor into a neon avalanche circuit, which in turn triggers the thyristor, discharges the main capacitor into the primary coil and creates a spark. The avalanche circuit discharges the timing capacitor as it sparks, so the cycle restarts and sparks occur every second or so.

However when the gas lights, the flame plasma conducts enough current via the high value resistor to stop the avalanche occuring, so the sparking stops.

[gogi]

Hello, CNC bobyst

[BOOJAN]

god damn people...i started building cnc machine, and i saw this winder, and i will spend my steppers on this project....unless if i find other motors for the winder....

btw very interesting project and i will build it this summer when i finish my cnc....

[CalG]

Glyptal might have a product for between layer insulation

It works for lower voltages,

http://www.glyptal.com/Glyptal_Product_Data_Sheets.htm

Inquire of their engineers.

Now if I could just get this old tractor magneto coil rewound.......

CalG

[BOOJAN]

does someone have some schematic for the controller...or how to control the stepper motors????

[amplexus]

Check out the cpld tutorial thread whem Mariss gets the rest of it up it will be the best open source controller at any price and it shoukd be cheap.

Amplexus Ender

[RomanLini]

Hey Synthesis, you put your ad in this thread, and when I went to your website to look at your coil winding machines it says I have to enter my email and phone number and stuff just to look at the "machine details"? That seems a bit rude!

[neilw20]

Over 30 years ago I was involved with winding EHT transformers for valve televisions. 20KV or so.

We would wind 10 or 12 side by side on the same cardboard tube, primary with taps, extra windings, etc, then the secondary.
As each winding layer was changing directions, without stopping the machine the operator would feed in a strip of very thin paper, just wide enough to wrap a bit more than 1 turn.

The tensioners were like fine fishing rods operating drag brakes, and fed through ceramic beads on the end of the 'fishing rod'.

Breakages were rare.

Once wound, they were cut into 10 or 12 pieces in a sort of lathe with a narrow slitting blade.

Then the start, and taps were fished out from the sides between the layers!!

Many layers. The whole lot was then vacuum impregnated with paraffin/beeswax. in electric frying pan with a 1" glass lid sat on it with a rubber gasket. We kept the fumes in!! It attracts swarms of bees!!!

There were also versions that used some sort of varnish, in a vacuum, then baked overnight.

[headsmess]

this has me thinking of an old project of mine i gave up on...winding guitar pickups.

(electric sitar pickups actually...)

the problem with the bobbins is that theyre long and narrow. i could never think of a way to feed 0.05mm wire without it snapping, other than the slow way.... hand and that still caused much anguish around turn 4538 when you snapped it accidently


the ideas resurfacing after having ripened i guess

ive had that bee problem before! never thought of sealing the pot though!

[neilw20]

Now with CNC it is fairly easy easy to make the tensioner/bobbin assembly track in and out on a guitar style oblong bobbin at reasonable speed, and even even servo control the tension better than a human can.

[RomanLini]

Agreed, humans are poor at tensioning very fine wires.

A CNC coil winder has been on my list of things to do for ages, although I really don't have any coils that need winding I just want the cool machine.

Thanks too NeilW for your experiences winding the old HT transformer coils. Some of those wax sealed cardboard tube coils were a real work of art (I worked in TV repair for many years in the old days).

[Smertrios]

I dont know about picking wire to use *but* here is a place selling enameled essex brand wire in 11 pound spools for a lot less per pound.

www.magnet4less.com

Maybe I underestimate just how much wire is in a pound =>

[bluejets]

I plan on using a PIC 16F870, with a 16 key keypad and LCD display. The display will prompt for wire size, length of the coil to be wound, and total number of turns. The two steppers will work in tandem, to provide linear movement / bobbin revolutions to space the wire properly. Winding speed will be controlled with a pot to feed an one of the ADC inputs on the PIC. The process will be to wind one layer, pause so insulating tape can be applied, then a key stroke will restart, moving the feed in the opposite direction, repeat, etc .


Ken

Just a thought for anyone wanting to go a slightly different route. This is a PLC program that runs on an old PC. I used it to build a crankshaft grinder for miniature engines and used optical switches, the kind from old printers etc. as limit switches. They are accurate to within 1 thou repeatedly. It operates in much the same manner only with an extra axis drive.
http://users.skynet.be/DCI_Site/dciplc.html