Dynamo & Burnt Out Armatures

[Bodge]

I have managed to burn out two dynamos in quick succession.

The first time back in June, I took the dynamo apart and found solder splattered around the commutator. I checked with a voltmeter and it showed that the armature windings had fused together. I fitted a new dynamo and everything seemed okay. The ignition light went out above idle speed and a voltage check of the output seemed okay. However today, having only travelled about 100 miles with the new dynamo, the red ignition light came on again. The armature of the new dynamo seems to have burnt out again as there are suspicious signs of solder around the commutator again.

The vehicle is a Mini Moke and has been running without any problems since I restored it three years ago. It had a new control box and a new loom. On both occasions it happened whilst driving along the same stretch of dual carriageway for several miles at 70mph. There was also an odd smell in the period just before it happened (although I only realise that with hindsight.)

Does anyone have any ideas? Would a faulty regulator or ignition coil cause this problem? Do you think it could have damaged the battery? Perhaps I just need to stop driving along that particular stretch of road heehee. Roger