A technique for maintaining tension on fiber drawn from a spindle includes incorporating a permanent magnet brake into a spindle and controlling tension of fiber paid out from the spindle by rotating an adjustment plate of the permanent magnet brake with a motor. In some examples, a motor (e.g., a stepper motor) is coupled to the adjusting plate of the permanent magnet motor through a set of gears, a timing belt, or a similar transmission medium. Mechanical advantage afforded through gear reduction allows a very small motor to control a large amount of braking torque. Motor control may be accomplished for multiple spindles with little power.