12v starter conversion

[Jonathan Hoffman]

Hi everybody,

I've been working on converting a starter to run on 12v and have run into a problem. The field coils have been rewired and the starter has been assembled. When I hook power to it I can get the shaft to turn about a 1/16" and then it won't turn any further. My question is, do you have to change how the brushes are wired? The diagram I was using for the conversion shows them being wired the same way they were when stock.

Thanks in advance

[Ron Patterson]

The Model T Ford 6 volt starting motor field winding is wired series/parallel.
When you convert it to 12 volt operation you have to change the field to full series.
Ron Patterson

[BobShirleyAtlantaTx]

Look up this thread, it explains the process.

[Luke]

Here's the actual link to the thread that Bob pointed out:

viewtopic.php?f=2&t=10169

[Art M]

In order to maintain proper North.....South on each coil, wire siagram must followed.
I suspect that some of the coils have the wrong magnetism polarity.

Art Mirtes

[Jonathan Hoffman]

These were the diagram that I followed when re-wiring the coils. Here's also a picture of the coils

[Art M]

Coils 1 and 4 must have the same polarity and coils 1 and 3 3 must have the same polarity but opposite that of coils 1 and 4.

To check this, with the armature removed from starter. Connect the starter to a battery, then touch each coil with a iron bar and see the polarity of each coil is with a compass.

[Art M]

Made a mistake. Coils 2 and 3 must have same polarity.
I entered a 1,instead of 2 in previous posting.

Art Mirtes

[Jonathan Hoffman]

I tested the coils. Coils 1 and 2 have the same polarity and coils 3 and 4 have the same polarity. I'm unsure about how I would go about fixing this so that the coils have the right polarity.

[Scott_Conger]

It appears that while you had things out to modify, coils got rearranged. You'll have to undo that error.