LINEAR MOTOR CURRENT COLLECTORS FOR SEA WATER USE

BRUSH COMMUTATING LINEAR MOTORS ARE BEING INVESTIGATED FOR USE IN A TORPEDO LAUNCHING ROLE. TWO KEY PROBLEMS ARE UNCERTAINTY ABOUT THE LIFE OF THE COLLECTOR SYSTEM AND OPERATION OF THE COLLECTORS WHILE SUBMERGED IN SEA WATER. THE LIFE OF THE COLLECTOR SYSTEM DEPENDS ON THE TYPE OF COMMUTATION. MOST DC COMMUTATING COLLECTOR SYSTEMS RELY ON AN ARC TO COMMUTATE THE CURRENT. EROSION OF THE COLLECTOR SYSTEM ACCOMPANIES THE ARC. THE EROSION CAN LIMIT THE LIFE OF THE SYSTEM TO A FEW SHOTS. OPERATION IN SEA WATER IMPOSES CORROSION, BIOFOULING, AND VOLTAGE STANDOFF DESIGN ISSUES NOT NORMALLY ENCOUNTERED IN COLLECTOR SYSTEM DESIGN. THESE ISSUES MUST BE ANALYZED AND UNDERSTOOD. IN ADDITION, OPERATING THE SLIDING CONTACT SYSTEM IN WATER WILL CREATE A HYDRODYNAMIC LIFTING FORCE THAT MUST BE ACCOUNTED FOR. THE LIFTING FORCE WILL TEND TO UNLOAD THE ELECTRICAL CONTACTS, AND INCREASE THE COMMUTATION EROSION. WE PROPOSE TO DEVELOP THE DESIGN OF A NON-ARCING, RESISTIVE COMMUTATION CURRENT COLLECTOR SYSTEM. THIS SYSTEM WILL ELIMINATE BRUSH EROSION AND WILL BE CAPABLE OF OPERATING IN SEA WATER.