Design of a magnetic bearing-supported prototype centrifugal artificial heart Pump

Magnetically supported ventricular assist devices are beginning to be developed. This paper describes a continuous flow centrifugal flow prototype pump that has been constructed and successfully tested. It has four active electromagnetic bearings-two radial and two thrust bearings. The total capacity, current gains and stiffness of the bearings are described. Bearing coil currents were measured with the pump rotor in various orientations to approximately determine the actuator current gains. These parameters were then employed to estimate the radial and thrust forces exerted on the pump rotor during static operation in air and water and then with the pump rotating in both air and water. Performance properties-differential pressure and efficiency-were measured and found to be in the range necessary for adult human cardiac requirements.