Type R Alternator

[MikeCollins]

I wonder if someone can help me. I was clearing out my grandfathers basement and I came across a box containing a De Havilland Type R 80V alternator. From the documentation, it appears to have come via a company called "Research Enterprises Ltd." which manufactured parts for the war effort up to 1946. Would anyone know what this is used for and if it is of any value? Any information you can provide me with would be appreciated greatly.

Thanx
-Mike.