Ebara Corporation

Hiroyuki Chino

Toshiharu Nakazawa

Matsutaro Miyamoto

Yuji Shirao

Atsushi Shiokawa

Minoru Iwata

Akiko Taira

Atsusi Ooyama

Toshiya Akasaka

Magnetic bearing control device and turbo-molecular pump device

A magnetic suspending device which can detect the temperature of a controlled object and assure a safe operation thereof without any need for any special construction or work to the device and any special maintenance is disclosed. In the magnetic suspending device comprising a pair of electromagnets (,) disposed opposite to each other, a magnetizable controlled object (,) disposed between the pair of electromagnets (,) and position displacement detection sensors (,) disposed opposite to each other for detecting a position displacement of the controlled object (,), wherein detection signals from the position displacement detection sensors (,) are inputted to a control circuit unit (,) for performing phase compensation and gain adjustment, wherein control outputs from the control circuit unit (,) control magnetic attractive or repulsive forces of the pair of electromagnets (,), and wherein the controlled object is magnetically suspended by the pair of electromagnets without contact at an arbitrary position, a temperature operational circuit unit (,) is provided for detecting the size and temperature of the controlled object (,) using the detection signals from the position displacement detection sensors (,).

Magnetic suspending device controlled by temperature of controlled object

A DC motor apparatus which can be started with a power supply having a small current capacity and which provides a large driving force. The DC motor apparatus comprises a permanent magnet in a rotor of the DC motor, a plurality of coils provided at a stator of the DC motor, a distributor for controlling the switching of current paths to the coils and a position detector for detecting a rotational position of the rotor of the motor to output switching signal to the distributor. A pulsating unit is further provided for pulsating currents supplied to the coils whereby a current flowing from the distributor to any one of the coils can be pulsated when the DC motor is activated, resulting in easy starting the DC motor.

Easily started DC motor apparatus

A displacement sensing circuit for sensing a displacement of a measured object without any contact with the measured object. A detecting coil is disposed relative to the measured object to be capable of changing its inductance in response to a displacement of the measured object from a predetermined position. An output signal from the detecting coil is passed through a band-pass filter. The filter has a frequency band width which is equal to at least twice the upper limit of a response frequency of the sensing circuit, thereby outputting a signal less influenced by a noise. An output from the band-pass filter is detected to provide a signal corresponding to the displacement of the measured object.

Displacement sensing circuit with coil and band pass filter for

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Tokyo, Japan

Hiroyuki Chino