As winter is coming soon I started to do some rebuild work I can do inside at the kitchen or living table.
First job was rebuilding a few coils I bought on Ebay a while ago.
Now I started the rebuild of a round double stack magneto ring 1909-1911, I think.
As it is the first time I am rebuilding this kind of magneto loop I have a few questions.
First I count the winding and I came on 21 for each single coil, Is this right??
As they were double it should be 42 for one coil assy. For the coil loop it will be 672 winding.
For the oval double this is 512 and for the single oval loops it is 400 winding? Why this change or is it a money question??
Do these early model T have an easier start on Magneto? ( More winding, better magneto performance??)
I am also looking for some pictures of the magneto terminal. I need to rebuild it and have not a complete one to copy.
Here is the one from #904. The MAG connection is just a piece of bent steel. These cars start very easily on MAG.
Sorry, I meant Andre!!!!!
It would be interesting if you would include some pictures of your rebuild. Not often we get to see a double stack around here. Thank you for sharing.
I don't know if these will help. The photos appeared in a one page review of the new Model T magneto, November 29, 1908, "The Motor Age:"
Courtesy Google Books, link:
I have designed a few coils and transformers during my career and you need to understand that the number of turns alone does not necessarily mean anything with regard to magneto output. The inductance of a coil depends on the size of the core as well as the number of turns and also the material that the core is made from. Since all of the coils in the Ford magneto operate together in series then also the coupling between coils can have an effect and of course the strength of the magnets and their distance from the core has a large influence on the final output from a magneto. In general when trying to get the maximum amount of power out of something and then trying to make the maximum use of that power the key thing that matters is that the output impedance (a fancy term meaning AC resistance) of the source needs to match the input impedance of the load. The maximum amount of power will be transferred in the most efficient manner when those conditions are met. I do not want to launch a long thread on that subject but only want you to understand that the number of turns on the mag coils is not simply a case of "more is better".
Is The Magnet polarity of N-S-N-S correct in the article?
I think there is a mixed up. For me it should be NN-SS-NN-SS.
Thanks John for the magneto explanation. Now I understand why my HCCT gives me about the same output with the double oval and the single oval coil ring. I build the HCCT with a self rebuild single oval coil ring.
After the first rebuild of a double oval coil ring, I put the ring on the HCCT and tried it out while testing a few, good working, ignition coils .
On both coil rings during the test I had between 2.5 and 2.8 V output. I expected over 3V for the double ring. On the double oval coil ring the core in the coils are smaller as the core of the single coil ring but there are more winding.
Here in the double round coil ring the cores are much smaller as on the single coil ring but there are 50% more winding. I wonder what will be the output on the HCCT.
For Dave Hjortnaes.
A few months ago I made some step by step photos during the rebuild of a double oval coil ring.
For the second rebuild I changed the size of the mandrel. The core was to small (didn't count on the thickness of the cotton warp).
Andre is correct the magnet ends must be oriented on the flywheel NN-SS-NN-SS, otherwise the magneto will not work.
Figure 3 above is marked incorrectly.
I wanted to share with you something I saw on my recent trip to Argentina. Jacinto Duretto is rebuilding Model T field rings in his shop in Sunchales, Santa Fe Province. In order to make the process quicker he developed a pattern and two piece die cut insulator in place of the sixteen individual pieces. The one shown below is for the oval pole field ring.
Here is a photo of two pieces I brought back to show to Wally Szumowski.
The ideal way to do this would be to laser cut them.
Ron the Coilman