Attached is a picture from the 3rd Armored Division historical website of a captured trailer with generator put into action at a 3rd Armored Command Post.

The Generator Unit inside is a Wehrmacht Unit. This was provided by another collector.

Well I can give an answer to the question about the generator, it is a Zundapp engine that is driving the generator .
The German indication for the set is Elektr. Machinensatz Evz 6D.
It is also in use by the german V-2 batterie placed in to the Steyr 2000 Spannungs versorgungswagen.

If anyone knows where on can be acquired I would like to buy it.