k2f actual wiring diagram

[coater87]

 Hello all,

 It has been quite a while since I have been around.

 I when back to school, and finished a couple of major remodels here at the house.

 Now its time to get back in the shed.

 I have read everything I can find on the internet, have searched high and low for this one bit of information. Its either never been posted, or I am searching for the wrong thing.

 Please, if anyone is positive they have an actual K2F wiring diagram, or anyone knows for sure that a web site has it, could you post it?

 I cannot tell you how many links I have followed, only to get the exploded view of the mag.

 I am taking the mag to work tonight, and am going to tare it down. My biggest concern is removing the windings and missing something. Whomever potted the winding last made a complete mess of it, and the entire thing is a solid mass of hard epoxy.

 No telling the trouble I will have removing it, so I need some back-up information if anyone has it.

 Thank you

[bsa-bill]

We have two (at least - sorry if I've missed another) experts on this forum so if you haven't already searched on here I would.

[groily]

You might find the schematics here could help you.
In terms of actual 'wiring' there isn't that much in there - a low and a high tension coil commonly earthed, with the live LT end attached to the 'nut' on the rear of the centre screw for the cb, and the HT spike stuffed (literally) into the slipring. The earth brush - on the flange end next to the timing case - provides the return path for the current. See http://www.brightsparkmagnetos.com/condensectomy/K_series_reconfig.htm
The thing to note with the K1/2/VF is the 'double' wire that gets the LT live back to the cb end through a groove in the bobbin - because the slip ring is at the 'wrong' end. If you've got a brass cb backplate, then the fixed point is 'live' (ie connected to the cb centre screw), if a steel assembly, then the moving point is.
Hope that helps.
Cheers,
Bill

[Triton Thrasher]

Take the safety gap screws out first.

[wilko]

Just buy another armature on ebay!

[coater87]

 OK,

 Last night, everything was carefully taken down.

 Couple things found, first was water. Not a lot, but some water got into a void in the potting.

 Second, the secondary side was open. I measured 1.3 ohms on the primary, which is correct for my meter, and infinite on the secondary. One lead of the secondary measure 500+- ohms to the bobbin itself, the other read in the Mega range.

 I drew some pretty good pictures, and now I will move on.

 Bill, good or bad, this one has the brass plate.

[groily]

Brass plate good in my personal opinion, far prefer them.
Water in the potting not good, may well suggest capacitor leakage when you test it, even if the thing is still good when bone dry. You want a capacitance, per Lucas, of between 120 and maybe 160nF, and you want it to be leak-free on a megga to a couple of Giga Ohms at 250v certainly, 500v better still.
OL secondary bad bad, 1.3 ohms primary is typical on meters that aren't 100%, and sounds OK. Should be 0.5 - 0.6 ohms and probably is, they usually are. Open Line HT coils often work for a good while as the spark jumps the gap inside -and makes the gap bigger over time - until it doesn't jump it any more). Should be no measurement from the iron bobbin itself to any of the wires when the capacitor is out and the coil is 'bare'. Should have the low reading between the LT tails, and something from 4000-6000+ ohms between either of the LT tails and the HT spike, depending on the winding recipe - wire gauge, number or turns etc. If you hold the coil with the HT spike facing away from you at 12 o'clock, the common 'earth' lead for the LT and HT should be at upper left, 10 o'clock as you look, and the LT live at lower right, about 4 o'clock. That's the one that doubles back on a K2F via a groove in the bobbin to get to the nut on the base of the contact breaker centre screw.
If in any doubt having got as far as this, it's not worth doing anything except get it rewound, replace the capacitor and maybe the slipring, have a few shims to hand to sort out the endfloat on the reassembled armature and it should be plain sailing thereafter.
Good luck,
Bill

[coater87]

 Bill,

 Here is how this mag was rewound.

 the winding had 4 leads coming off. the LT leads both went to the capacitor, a black and silver suitcase (original?) looking one, one side grounded right along with the cap.

 The HT leads- one went to the slip ring, and the other went to the center screw for the points.

 Does that sound familiar?

 

[wilko]

Masochists! I suppose somebody has to do it!

[groily]

Sounds familiar, but not quite what it seems! The wire going to the centre screw base is a Low Tension coil wire, the live one. That is the end of that DOUBLED UP wire that comes BACK from one side of the condenser - the one at 4 o'clock as per my previous comment. So really there are only THREE wires on a bare coil. The condenser has to be in parallel with the points obviously, and the only way to do that when the condenser is the 'wrong' end is to double back, which is what Lucas did on all K series (but not on M01 Magdynos etc etc because they were built the other way about). The other wire to the condenser is the LT earth as you say, which  is a common earth for the HT as well. The electrical path back to the earthed electrodes of the spark plugs is then made by the earth brush, which is next to the flange at the drive end on a K2F and connects the armature brass cheek to the bike. The bearings are supposed to be properly insulated so that their use as an electrical pathway doesn't eat them away  . . . .
So  . . .  you should get your simple HT resistance, say 4000 to 6000+ ohms between either of the LT wires and the spike on the HT coil - and you won't see the difference on the meter whichever LT wire you hook up to the spike because the LT resistance is less than I Ohm. And you should get no reading between any wire and the iron of the bobbin if ther coil is bare. If you do, the insulation has failed big time. What we're looking at here is a very small alternator - the LT coil - and a transformer (the HT coil). The 'silver suitcase' condenser is probably an original fitment, and will almost certainly be leaky as it's a paper job. Mica ones are miles better, which is why some people swear by BTH who used them forever, and also why some magdynos etc seem to last for ever. I dug out a Mica one from a pre-war instrument the other day which was inscribed "10 November 1930" by whoever fitted it and it STILL tested good. (Shame about the coil though).
Cheers,
Bill

[trevinoz]

Just a point, when checking the resistance of the secondary winding, make sure that the wire is contacting the slip ring with a good connection. Quite often there is corrosion in there making a high resistance joint, if it can be called that.

Trev.

[coater87]

 Thank you guys!

 First, I believed I had found four separate wire ends coming from my coil- because I had continuity between only two of them.

 After our discussions and some research and splitting the coil, here are the troubles I found and the actual way it was rewound and then potted badly.

 First was the capacitor (a suitcase cap with one side black bakelite and one side metal case) which Grolly believes is original and may have been re-used(?) when the magneto was rewound. This was grounded on the metal side. Whomever redid this coil, used about 1 entire ounce of solder to hold the capacitor in the end cap. There was a metal retainer over the cap held down with two smaller internal screws. Enough solder was used to fill the heads of the screws and nearly cover the bar.

 The primary (heavy gauge) wire was grounded into the solder mess of the capacitor, wound 208 times around the bobbin, then connected to the bakelite side of the cap. This followed what I believe is correct. There was no insulation between the winding layers of the primary, but I am pretty sure there should have been.

 The secondary side (very thin wire) was incorrectly wound from everything I have read and Bill kindly explained to me. One side was not grounded, but connected to the black side of the capacitor instead of grounded as it should be, and it was electrically open showing no continuity to the "spike" that connects into the slip ring.

 There is also to be a wire that should go from the solder puddle (ground), across the coil to the to center bolt for the points. This was not run that way, the wire was simply bared back and globbed to the bobbin, in an attempt to make a ground. this was so badly done it showed mega-ohms (millions of ohms) of resistance to ground. It should have been less then 1 ohm.

 Then it looked like it was intentionally filled entirely with some type of semi-hard goo.

 Now I am an industrial electrician by trade, but this is not the type of thing I normally work on at all. The closest I get is the occasional D.C. motor-generator set. Other then that, times have moved on to much more computer driven automation.

 I believe my next step is uncertain. I am either going to look for someone to rewind the bobbin, and I am confident in doing the rest myself, or I am going to order what I need to attempt to rewind it myself.

 I have looked and believe I need 24 gauge magnet wire, and about 6000 feet of 40 gauge. I need some fish paper or other heavy material to line the iron bobbin, mylar to insulate between the layers of windings, a new capacitor, and some type of vacuum resin to impregnate the winding.

 Thanks guys,
Lee

[groily]

Hi Lee,
It's a bit hard to tell whether there was actually an error in the thing, or whether, because it's failed, things aren't doing what they should! But anyway, about 200 turns on the primary is right; one end to ground at the condenser 'metal' side (common with HT), other end to the 'live' side of the condenser and doubled back to the contact breaker centre screw.
A break in the HT winding and/or an insulation failure will give you all sorts of funnies & confusion. Big blobs of solder which bury the heads of those 2 small BA screws is usual! The suitcase might have been reoplaced, but it might have just been stuffed backin if it tested so-so last time the thing was apart. NOS (paper) condensers are a big No No, as they will often have deteriorated over time.
Brave of you if you're going to rewind it - others will give better advice on wire gauge, insulation materials etc. Brufnut (I think he's called) in Germany did a great series of pix and descriptions a few years back - might be worth a squint/google.
Over where you are, Mainely Magnetos would probably help out if you want someone else to do it, or you could talk to Skip Brolund in OH at sbrolund@yahoo.com.
That's about all I can think of from where I am - but it's obviously got to be redone now!
Good luck,
Bill

[KenF]

Since a picture paints a thousand words, Lee, have a look at the attachment. Hope it makes sense.

Sounds to me like yours was wound correctly. The old condenser would originally have had neat little solder tags for the winding tails at that end.

Good luck,

Ken
brightsparkmagnetos.com