Field Coil Winder using a Sewing Machine Motor.

[Radio Fixer]

Thanks Alan

I do have a nice condition AVO signal gen in the cupboard !

Gary

[Yorkie]

I thought I'd awake this thread from its slumber to update it.
I'd earlier mentioned that using a pocket calculator as a turns counter is fine up to perhaps 100RPM - for example in a hand winder, but the calculator ceases to count at much above that speed. I therefore removed the calculator/micro-switch arrangement and fitted a mechanical 'tally-counter' operated by a cam and lever. It worked reliably, but is a bit 'agricultural' and makes a clatter in use. (I've attached a pic).

As a better alternative I searched for a sensibly priced shaft counter to attach directly to the coil winder shaft. I eventually found one for under a tenner, which I've now fitted, and which seems to work well. The spec is:

Range : 0-99999;
Max Rotation Speed : 350 r/min;
Shaft Diameter : 6mm/ 0.24"
Body Size : 8.5 x 5 x 5.7cm/3.3'' x 2'' x 2.2'' (L*W*T);
Total Length including shaft: 16.5cm/6.5";
Mounted Hole Diameter : 5mm/ 2"
External Material : Metal;
Colour : Grey, Silver Tone

http://www.amazon.co.uk/dp/B00EZ4BDEE/re...71_TE_item

The body is quite large, but that's no bad thing as the digits are large too so are easily seen as the counter increments the turns. Although it states maximum RPM 350 (ie, 3,500 turns in ten mins), I've run it faster than that just for devilment and it seems to be quite happy, though if - as I suspect - the gears are plastic, it might not be up t5o prolonged use at faster speeds.

I've also got a cheapo pedometer which includes a 'step counter' which operates by a small weight on a sensitive spring bouncing up and down with each step taken, shorting out two contacts. As with the pocket calculator, the spring/weight could be removed and those contacts could be connected to a micro-switch operated by a cam on the coil winder shaft. However, as with the calculator, the pedometer isn't designed to operated at say 500 steps per minute, so it might suffer from the same shortcomings as did the calculator. I was intending to give it a try, but with so many other commitments, so many half-done projects, and several weeks away from home over the next three months, it isn't going to happen.

The first pic is the new shaft counter, the second pic is the cam & lever operated tally counter, the last pic is new shaft counter alongside the diminutive pedometer/step counter, which I suspect will only get used for when we're on walks. We're off to the Dales in a week or two, so we'll take two (they were on a BOGOF' offer at Mountain Warehouse) to see how they compare.

(I managed to finalise an article on the coil winder and submit it to Carl Glover for his consideration, but he's extremely busy right now, so I'll await his verdict in due course as to whether it merits space in the Bulletin).

Hope the pics are of interest.

[Alan Douglas]

I prefer the mechanical turns counters; if you back off a few turns to correct something, the counter still keeps track. On my winder I have a three-digit counter driven by a 100-tooth gear meshed with a worm (1/4-28 thread actually) cut into the shaft. So it counts tens, hundreds, thousands. I can estimate single turns.

[Refugee]

I have a part built home made winder.
As a counter it has an industrial conveyor batch counter with a nixie tube display. It is driven by a reflective opto device and can count as fast as the 74 series electronics within.
It also has a set of switches that a valve tester owner would kill for that program a relay to operate at a set count.
The power comes from a modified ice cream maker.

[Yorkie]

I prefer the mechanical turns counters; if you back off a few turns to correct something, the counter still keeps track.

Yes, the new shaft counter is just as happy going backwards as forwards, so for example of you wanted to wind on say 2,000 turns and went a bit too far, you could remove turns and the counter would count down till you got back to 2,000 (or whatever). I guess it could also be used to count turns off an open circuit transformer winding say, to see how many turns there were originally, to enable the same number to be wound back on. (assuming of course that the original winding wasn't burnt out, but was simply O/C).

[Alan Douglas]

Yes indeed, I've unwound old coils and the counter does all the tallying. I just remove the drive belt (o-ring) and the mandrel rotates freely.