Dick:
If you're talking about the horsepower resistor, that tells the KB drive what the current limit to the motor should be set to.? It also tells the drive how to respond to a varying load, at least it gives the drive a rough setting.? There are pots on the board that allow fine tuning of the drive if it's not performing to your satisfaction.? Fuse the drive appropriately and it should last you a lifetime.
Be sure to REALLY thank whoever gave you that drive, your set-up would cost you a couple hundred bucks to purchase new off the shelf.
Don
