Magneto Armature Windings

ogrilp400

Well Known and Active Forum User
Non-VOC Member
Dear All,
Does anyone know who supplies Lucas magneto armature windings, as in the windings on the bobbin? Yes yes I know that there are lots of magneto reconditioners out there but some are not very reliable so it looks like another job I have to do myself.

Phelps.
 

chankly bore

Well Known and Active Forum User
Non-VOC Member
Dear All,
Does anyone know who supplies Lucas magneto armature windings, as in the windings on the bobbin? Yes yes I know that there are lots of magneto reconditioners out there but some are not very reliable so it looks like another job I have to do myself.

Phelps.
If you haven't already, read Magnetoman's exhaustive and erudite postings on the Britbike Forum re reconditioning a magneto. I'm too technologically backward to post links and suchlike. Windings are but part of the problem. Capacitors are another item which can prove to be a broken reed-and then there are faulty repro parts and people who lack the capacity to re-magnetise to sufficient strength. See me at the next Section meeting, Phelpsy. I will have a correct capacitor in my pocket; and if you've got 30 seconds I'll tell you all I know.
 

chankly bore

Well Known and Active Forum User
Non-VOC Member
The thread on Britbike forums is entitled "Restoring a rotating armature Magneto" Grab a big beaker of strong coffee, tape your reading glasses on and "read, mark and inwardly digest''.
 

vibrac

Well Known and Active Forum User
VOC Member
Hats off to anyone doing that work very high concentration and skill, I would rather set up preload on BMW R twins rear taper roller bearings (Don't ask)
 

greg brillus

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VOC Member
The rewound cores are available on EBay, trying to rewind your own without all the correct gear including a vacuum tank and a winding machine would be unrealistic. It is more specialized than one might suppose. Remember the secondary comprises of around 12000 turns of wire as thin as the hair on your head, wound on in a 200 turn pass, then a layer of thin insulation between each layer. If this insulation is too thick, then you won't get enough turns of secondary wire resulting in a weak spark. This thin secondary wire needs to be soldered at it's start and finish points finishing in the output wire, this all needs to be wrapped carefully in Egyptian cloth tape, then soaked in a resin bath of the correct type, and left in a vacuum to evacuate any air trapped in the windings. It is then baked in an oven to set the resin, the excess trimmed, thread holes unplugged, then it is ready. There is a lot more to it than I have explained, in particular, the initial preparation of the core, plus making up all the pieces that form the insulation, to shield the primary windings from the core itself. From memory I could finish a complete core rewind in less than a day.....All done by hand, no automation at all. Cheers...........Greg.
 

ogrilp400

Well Known and Active Forum User
Non-VOC Member
If you haven't already, read Magnetoman's exhaustive and erudite postings on the Britbike Forum re reconditioning a magneto. I'm too technologically backward to post links and suchlike. Windings are but part of the problem. Capacitors are another item which can prove to be a broken reed-and then there are faulty repro parts and people who lack the capacity to re-magnetise to sufficient strength. See me at the next Section meeting, Phelpsy. I will have a correct capacitor in my pocket; and if you've got 30 seconds I'll tell you all I know.
Thanks Charlie, see you at the next meeting.
 

ogrilp400

Well Known and Active Forum User
Non-VOC Member
The rewound cores are available on EBay, trying to rewind your own without all the correct gear including a vacuum tank and a winding machine would be unrealistic. It is more specialized than one might suppose. Remember the secondary comprises of around 12000 turns of wire as thin as the hair on your head, wound on in a 200 turn pass, then a layer of thin insulation between each layer. If this insulation is too thick, then you won't get enough turns of secondary wire resulting in a weak spark. This thin secondary wire needs to be soldered at it's start and finish points finishing in the output wire, this all needs to be wrapped carefully in Egyptian cloth tape, then soaked in a resin bath of the correct type, and left in a vacuum to evacuate any air trapped in the windings. It is then baked in an oven to set the resin, the excess trimmed, thread holes unplugged, then it is ready. There is a lot more to it than I have explained, in particular, the initial preparation of the core, plus making up all the pieces that form the insulation, to shield the primary windings from the core itself. From memory I could finish a complete core rewind in less than a day.....All done by hand, no automation at all. Cheers...........Greg.
G'day Greg,
No I don't want to rewind it myself, I want one already done so I can fit it into the armature ends myself.

Phelps.
 

Magnetoman

Well Known and Active Forum User
VOC Member
I don't want to rewind it myself, I want one already done so I can fit it into the armature ends myself.
Most of the rewound armatures I see for sale lack the registration pins that align the center section with the two endcaps. That said, I don't know if those pins are in precisely the same locations on armatures Lucas made in, say, 1950 as ones made in 1960. I've always managed to rewind armatures that left the factory as one unit, rather than ones pieced together.
 

chankly bore

Well Known and Active Forum User
Non-VOC Member
Back in the70's in Melbourne there was a bloke called Neil Mann who did magneto and generator work. I remember him telling me that he could get the three sections of any B.T.H. armatures, assemble them together, and they would run true. Lucas, on the other hand, assembled the three parts and then trued the assembly. Whether this is true or not, I don't know. There was a song in M.P.H. around the same time; "Old Joe Lucas, oh don't you cry for me. For at night I ride my Vincent with a torch strapped to my knee!" I got a B.T.H. done by Neil- still reliable.
 
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