The Thermo Electron Research and Development Center will develop torque motor to blood pump drives, Specifically, they will attempt to improve the torque motor to pusher plate design by incorporating a solid state commutator to eliminate brush wear and improve efficiency and to redesign the motor to provide, with the solid state commutator, a second generation inverted torque motor. They will also further investigate and develop the cam and cam follower system. Extensive in vitro testing is to be carried out in the first two years for performance characterization and reliability. Twenty-eight in vivo tests are planned. These tests are to begin immediately with upgraded systems used as they become available. Data management of tests is to be undertaken to achieve two objectives: obtain significant data, and compress it to manageable proportions.