Six-phase cylindrical linear pulse motor as linear oscillatory actuator

A trial construction is described of a six-phase cylindrical VR type linear pulse motor which has been developed as being applicable to the linear actuator for the assist artificial heart. The VR (variable reluctance) type motor has a smaller thrust/input ratio than the PM (permanent magnet) type motor, but is superior in low noise and high-speed operation. The trial construction has made use of this advantage. According to the static thrust characteristic of the linear pulse motor, increase in the number of exciting phases to six is effective to suppressing the thrust regulation, resulting in stable operation. As to the kinetic characteritics, the capability of the motor to be driven at low frequencies leads to such a great reduction in iron loss as to make possible the continuous operation with a kinetic thrust of 160 [N].