Hitachi Koki Co., Ltd.

Tsutomu Takamura

Masahiro Inaniwa

Noriyasu Matsufuji

Shinji Watanabe

Masaharu Aizawa

Yoshitaka Niinai

Shoji Kusumoto

Takahiro Fujimaki

Masanori Yoshioka

Kouiti Akatsu

A desk-top centrifuge is provided which includes a switching element disposed between a dc power supply and a motor and a controlling circuit. The controlling circuit receives a voltage of power regenerated by the motor to provide a pulse width-controlled on-off signal to the drive switching element to control speed of the motor. The controlling circuit increases an on-duration in which the on-off signal is at an on-level at a given rate to turns the motor slowly. The centrifuge has a safety guard system made up of a door switch and a door lock switch which are installed in series between the dc power supply and the motor and work to establish electric communication between the dc power supply and the motor when the door is closed and locked.

Desk-top centrifuge having improved safety in the event of an operational failure

A centrifugal separator comprising: a rotor for containing a sample; a rotating unit; a detection circuit for detecting a distance between a reference position and a position of the rotor and generating a distance detection signal; a rectifying circuit for half-wave rectifying the distance detection signal; a judging circuit for judging the distance detection signal from the rectifying circuit; and a controller for controlling the rotating unit in accordance with a judging result of the judging circuit and a corresponding method are disclosed. The judging circuit judges whether the distance is in a balanced condition of or an unbalance condition of the rotor. A centrifugal separator comprising: the rotor; the rotating unit; a detection circuit, having a given detection range, for detecting a distance between a reference position and a position of the rotor and generating the distance detection signal, the given range covering a deflection range of the rotor due to whirling on the side of the detection circuit with respect to a rotational axis of the rotor; the judging circuit for judging the detection signal and the controller for controlling the rotating unit and a corresponding method are also disclosed. The detection range may be assigned to an inhibit deflection range due to whirling of the rotor.

Centrifugal separator and a method of detecting unbalance of a rotor

A centrifugal protection apparatus including: a rotor having markers connected to a motor responsive to drive signals; first and second detectors for detecting the marker upon rotation of the rotor and generating first and second detection signals respectively; a drive circuit responsive to a command for generating the drive signals from the supply power via input terminal in response to the first or second detection signal; first and second switch circuits, arranged in series between the input terminal and the motor, for controlling the supply of the drive signals to the motor; a current detector for detecting a current of one of the drive signals and generating a current detection signal; and first and second judging portions for detecting whether the first and second detection signals are within a predetermined value and for operating the first and second switch circuits to cut off the drive signals when the first and second detection signals are not within the predetermined value respectively and when a magnitude of the current detection signal is larger than the predetermined value when the second detection signal is not generated. The first and second judging portions, first and second detectors, and the current detector operate in parallel and independently. The first and second switch circuits are arranged in series to provide more dependable protection.

Centrifugal apparatus having series-implemented protection means

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Hitachinaka, Japan

Tsutomu Takamura