Is this t ?
It's a stationary engine governor
Is there something missing?
Jay has it right, used on buzz saw's generators and such.
I think it is missing the fly weights off the front, like this one that I have.
"Is there something missing?", yes, the engine.
I have a home made one of those using two timer rollers for the flywheel weights. I have several things made from T parts back in the day that should be in a museum somewhere. I had a metal lathe made from T parts that is on display at the Montana Ag Museum in Fort Benton. Lots of ingenuity when there is not a lot of money around.