Hitachi Koki Co., Ltd.

Hitachi Koko Co., Ltd.

Noriyasu Matsufuji

Masahiro Inaniwa

Shinji Watanabe

Takahiro Fujimaki

Nobuharu Kido

Yoshitaka Niinai

Yoshinori Tobita

Satoshi Numata

Tsutomu Takamura

Kazuyoshi Tokunaga

Shoji Kusumoto

Katsunori Akatsu

Osamu Kawanobe

Mitsutoshi Yotsuyanagi

Kahoru Takahashi

Hisanobu Oyama

A centrifugal separator includes an input section for allowing a user to enter operating conditions of a centrifugal separation of a sample accommodated in a rotor driven by a motor. A memory of the centrifugal separator stores a user ID code and a corresponding user name which are registered in advance by the user. Operation of the centrifugal separator is allowed when a user ID code entered through the input section agrees with the registered user ID code.

Centrifugal separator and administration of user and actual operation of the same

A transformer outputs different (high or low) secondary voltages. A switch outputs high or low secondary voltage according to a mode signal. An electric power converter including a rectifying circuit and a switching circuit either charges a smoothing capacitor with an output of the switch or discharges the smoothing capacitor to supply a regenerative current toward the transformer with a power fact improved. An phase signal generation circuit generates PWM or PAM phase signals in accordance with the mode signal. An inverter circuit generates driving signals supplied to the motor in response to the phase signals from power from the smoothing capacitor. A mode determining circuit determines one of modes to generate the mode signal in accordance with a speed command signal and acceleration/deceleration which is indicated by the rotating speed signal and the rotating speed command signal.

Motor control apparatus

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 power control apparatus for controlling power supplied to an electric motor rotating a rotor employed in a centrifuge is provided. The power control apparatus includes first and second inverters and a smoothing capacitor disposed between the first and second inverters. In a motor power mode, the first inverter charges the smoothing capacitor with power supplied by an AC power supply, while the second inverter charges, in a motor braking mode, the smoothing capacitor with power regenerated by the motor during a braking operation for returning the regenerated power back to the AC power supply through the first inverter. An reactor is arranged between the AC power supply and the first inverter for reducing harmonic components contained in the current supplied from or back to the AC power supply.

Motor control system for centrifugal machine

A centrifugal apparatus includes a rotor having a marker for generating an index signal, a motor for rotating the rotor, first and second detectors for detecting the index signal with rotation of the rotor to generate first and second detection signals, an input terminal for receiving supply power, a drive circuit for generating a drive signal from the supply power according to the first detection signal, and first and second switch circuits for controlling the supply of the drive signal to the motor. First and second judging portions are used to detect whether the first and second detection signals are respectfully generated within a given condition. The first judging portion operates the first switch circuit to stop the drive signal from being supplied to the motor when the first detection signal is not generated within the given condition, while said second judging portion operates the second switch circuit to stop the drive signal from being supplied to the motor when the second detection signal is not generated within the given condition. The first and second detectors, judging portions, and switch circuits, respectively, independently operate to provide double feedback loops, so that an overspeed or the like is prevented.

Centrifugal apparatus with overspeed protection

A motor control system for controlling power supplied to an electric motor rotating a rotor employed in a centrifuge is provided. The motor control system includes first, second, and third converters and first and second smoothing capacitors. In a motor power mode, the first converter operates to transfer the charged energy in the first smoothing capacitor to the second smoothing capacitor for providing power to the motor through the third converter, while the second converter transfers, in a motor braking mode, the charged energy in the second smoothing capacitor to the first smoothing capacitor to return the power regenerated by the motor during a braking operation to the AC power supply through the first converter. The second converter performs a function of providing an initial energizing energy to the motor for a given period of time at the start of the braking operation for stability of a power-regenerating operation of the motor.

Motor control system for centrifuge

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.

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Hitachinaka, Japan

Noriyasu Matsufuji