Nippon Densan Corporation

Mineyo Endo

Itsuo Miyaji

Noriaki Hishida

Kiyoyoshi Takegami

Yosuke Kawate

Starting, accelerating and rated rotation of a rotor is carried out without any detector for the rotor position. A motor is controlled with an openloop circuit a short time in a starting area of low speed rotation, and thus the motor can be certainly started. In a rated rotation area, turning timing of the motor is precisely controlled by detecting counter-electromotive force of a stator coil.

Starting and control method for brushless DC motor

A magnetic fluid seal assembly comprising an annular sealing clearance communicating with an external space, an annular permanent magnet for forming a magnetic field in the sealing clearance, a ferromagnetic fluid retained in the sealing clearance by the magnetic field but rotationally movable in the sealing clearance, and a scattering preventive portion provided axially outwardly of the sealing clearance for preventing the ferromagnetic fluid from scattering to the external space when the ferromagnetic fluid is rotationally moved.

Growing community of inventors

Oumihachiman, Japan

Mineyo Endo