GPU and turboprop

[rasmusa]

If a turboprop engine brakes it propeller to a stop, turbine still running, will it then be called a GPU? Had a test the other day, and my teatcer ment it was so, but isnt a GPU a unit wich must be stationary on the ground and plugged to the a/c. I agree that it can serve as a replacement. Do anyone know the defenition of a GPU, or even better give me a link to where I can find one.