Model A starter motor

[Tony Hillyard]

Good Morning all,

I've cracked it! I've found the problem. While using 12 volts on my Roadster 6 volts starter didn't actually burn it out it showed up any weakness which stopped it working. In this case it must have been worn earth brushes plus the commutator was in need of skimming. Plus it was seriously dirty in there.

The commutator was skimmed, the segments cleaned out, new earth brushes fitted, interior cleaned out but when assembled she would not work.

With the starter in pieces again I carried out all the tests I could find with the exception of a growler, I would still like to get hold of one of those for the future. Every test showed everything was fine. I took the starter off my 1928 Tudor Sedan, stripped that down and did a direct comparison. With exactly the same test results on both motors.

Now I know what the problem was I don't know whether to feel relieved or stupid.

Apart from the meter tests mentioned above, part of the problem I find with starters and dynamos is you can't easily see what is going on inside as they are so heavy and awkward. I happen to have a hole in my work bench for a turntable to enable me to turn a piece of work while I am welding it.

With the starter partly assembled I put the shaft of the motor through the hole in the bench. So the starter was fixed and vertical. This enabled me, with the help of a pocket torch, to look down through the starter. When I gently inserted the two long bolts that hold the motor together it looked like one of the long bolts was very very close to one of the solid uninsulated electrical connections at the bottom, between the the field coils.

And so it was, as the starter motor was finally assembled and tightened each time this long bolt just touched the uninsulated connection causing a direct short circuit.

So like most problems, once you who the solution it's obvious!!!

Thanks to everyone for all their hep and advice.

[Tony Hillyard]

"New Roadster" supergnat, as requested. She is 1928 Standard Roadster.[IMG]/Users/hillyardeu/Pictures/Roadster front.jpg[/IMG]/Users/hillyardeu/Pictures/Roadster rear (1).jpg

[30aadoodlebug]

Thats great news Tony! Never, ever, feel stupid with anything in this hobby. As many of the experts have posted before, "everytime a newbie does something stupid we all learn from it." Glad to hear both your cars a running again.

[Tom Wesenberg]

Starter switch screws can also touch and short the field windings if they are too long. Same thing with generator cutout mounting and terminal screws.

[Brentwood Bob]

It's called experience.

[Big hammer]

Sponsored Links (Register now to hide all advertisements)

Thanks for the update! Great news you fixed it! This helps us all learn on things some us don't work on all the time. Sorry you had to learn the hard way, but it's fixed !!!!!!