AN ELECTRICIAN WAS WORKING ON A MAGNETIC BRAKE ON THE #1 SHIP UNLOADER. THE MAGNETIC COIL ARMATURE WAS NOT OPERATING PROPERLY DUE TO DIRT BUILD-UP. THE ELECTRICIAN STARTED WORKING ON THE ARMA TURE WITHOUT DE-ENERGIZING THE MAGNETIC COIL. THE COIL ENGAGED CAUSING THE ARMATURE TO SHIFT DOWNWARD. THE ELECTRICIANS RT.THUMB & RT. INDEX FINGER SUSTAINED A LACERATION REQUIRING SUTURES.