[Dave Scheck]

As Squirrel said, connect to a speed controller (Victor or Jaguar) instead of a relay. A relay only allows you to go full forward, full backward, or off. A speed controller will give you the full range from full forward to full back. Think about your drive motors. I can guarantee that you don't have them on a relay. Why did you make that decision? Because you wanted a variable speed. You should use that same thought process for the use of your globe motor.