When at a classic vehicle event I mentioned that I had refluxed my own magneto and I was asked how I did it. The subject has also been raised on the Panther E-mail group, so for what its worth, here it is.
This method uses the stator of an old burnt out 1/4 hp single phase electric induction motor. The motor is stripped down to the field stator and the burnt out "run" winding is removed. This is the fine copper wire winding of the motor. The thick copper starter winding is left in situ with a number of empty slots along side it.
A second dead motor was also stripped and the start winding was re-wound into some of the empty slots of the original run winding. Thin wooden strips are pushed into the T shaped slots to secure the windings in place.
What I now had is four coils with eight ends to connect to my Mig Welder and I needed to connect them all to produce a North - South alignment in the same direction. (See Picture One above). This was achieved using an ordinary torch battery and a compass. I placed the compass across the middle of the stator from one pair of coils to the other and found the needle aligned itself in line with the axis of the coils. This was due to residual magnetism in the stator.(See Picture Two)
I noted the alignment of the needle and now connected the battery to the ends of coil 4. The needle swung around. If it hadn't I would have reversed the connection of the battery. I marked the side of the stator that the needle pointed to as North or N and the wire on the positive end of the battery as +ve or P. (See Picture Three)
You now need to do this with the other three coils. When completed I joined the four ends marked P together and the four ends marked N together. This gives you four coils in parallel all producing North - Souths in the same direction. The Ns I connected to the earth clamp of my Mig Welder and the Ps to the centre of the wire feed nozzle with the gas shield removed. I was careful to make sure I had no feed wire or gas in the welder. I also checked the feed roller was unclamped and feed set to minimum and welder output set to maximum. On my welder this gives a maximum voltage of 70 volt and a maximum possible current of 120 amps. In all probability, this high current would not be achieved due to the resistance of the coil windings , but it may be, I have never measured the actual current flow. Resistance to the DC current from my welder is very much lower than the impedance to AC 50Hz mains that these coils originally experienced. When you energise do so only briefly as you will rapidly heat the coils and may well be overstressing your welder.
I insert the magnet to be energised between the coils and pack the space to the pole faces with odd bits of steel lying in my scrap box. I then pull the trigger of the Mig Welder three or four times holding it only for a second or less each time. I then ensure a "Keeper" is across the poles of the magnet until it is safely back together as a working Magneto. For Lucas revolving coil Mags I simply pack out the pole peices keeping them apart with wood to give a good magnetic gap that will go inside the body of the Lucas Mag. Crude but it does work. Remember your Norths and Souths have to play "chase me charley" that is North of Coil to South of Magneto and North of Magneto to South of Coil.
If you copy this method you do so at your own risk. Magnetic fields have been implicated in bone cancer. If your wiring is not adequately insulated the result will be an un-intentional weld arc, fire, explosion etc. Stand well back and wear eyeshields. You may also risk ruining your Mig Welder. My last effort magnetised my files in a drawer underneath the bench. It makes for neat filing as all the steel swarth stays stuck to the file. Oh well! It'll wear off eventually, just like the Mags do!
If you doubt that this method of using a Mig Welder and motor stator works, then please click this link to the Phoenix Page Two and look at the images of the Phoenix pump engine and its Magneto. Image four in the top row of thumb nails gives an idea of the magneto's original condition and image three and four in the lower row gives a picture of the engine and pump restored and working. The Magneto was rusted solid and had to be heated with a blow lamp to expand the alloy casing off the magnetic rotor this heating seriously de-magnetised the rotor. The coil was re-wound by hand, the rotor was re-magnetized, new points, condenser and bearings fitted. The engine now starts reliably on the hand crank. QED
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