Vintage DC generator
I'm not sure what your question really is.  The specs seem quite clear.

volts 9.12, kw .120, rpm 1350, winding CPD, amps 12,cont duty

This means that if you rotate it at 1350 RPM (22.5 Hz), it can put out 9.12 V at 12 A.  The claimed power output is 120 W, although from the voltage and current we get (9.12 V)(12 A) = 109 W.  Close enough, I guess.  The "cont duty" part means continuous duty, which tells you that it can supply the 9.12 V and 12 A for long periods of time.  In other words, these are not short term peak ratings.

The spindle at right looks like it was meant to be driven by a belt.

120 W is not much to run a farm house on.  This probably just meant a few lights.  Nowadays you could get much more light using efficient LEDs.  This thing could nicely light a typical farm house using modern parts.