Steve,
A friend of mine, who lives nearby, has a Modern Power Hammer almost identical to yours. It is running and even has the indexed handle on top that allows for hammer force adjustment. If I remember correctly, the drive is on the left side as you would use the hammer. He has 240VAC single phase motor to drive it, but I didn't note the horsepower. I'll to get some pictures and more detailed informstion, but it would probably best for me to take you to his shop the next time you're in my area.
Bob Stormer