Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Forschungszentrum Karlsruhe Gmbh

Toru Oka

Hajime Nakajima

Hiroshi Nishizawa

Keita Mochizuki

Yoichi Ohmura

Masahiro Shikai

Masahiko Sakamoto

Yoshiharu Kaneda

Akihide Shiratsuki

Kazunori Ikegami

Takashi Okamuro

Hirokazu Sakuma

Toshiro Nakashima

Yoshimasa Watanabe

Toshikazu Kitagaki

Jurgen Mohr

Ulrike Wallrabe

Uwe Hollenbach

Takeshi Musha

Kiyoshi Yoda

Toshiki Tanaka

Hirotaka Muto

Koichi Sugimoto

Ryuichi Nishiura

Kazuo Takashima

Yoji Tsutsumishita

Yoshikazu Tsutaka

The invention is related to a device for detecting insulation degradation in an inverter-driven load device, in particular a motor, the device including: zero-phase current measuring means for measuring a zero-phase current in power-feed lines, provided in the power-feed lines between an inverter device and the motor; and command control means for putting rotation of the motor on standby; wherein the zero-phase current measuring means measures the total of phase currents fed into respective phases so as not to rotate a shaft even when an external force is applied to the shaft during the rotation being on standby, whereby allowing regular detection of insulation degradation without switching over the power-feed lines connected with the load device.

Device for detecting insulation degradation

The invention is related to an insulation deterioration diagnostic apparatus for an electric path connected between an inverter device and an inverter-driven load device, including: a zero-phase current transformer having an annular magnetic core, a magnetizing coil wound around the magnetic core, and a detecting coil wound around the magnetic core, the transformer being for detecting a zero-phase current of an electric path; a magnetization control circuit for supplying an alternating current having a frequency at least twice as high as a drive frequency of the load device to the magnetizing coil to magnetize the magnetic core; and a frequency extracting circuit for extracting a frequency component identical to the drive frequency fd, from the output signal of the detecting coil, whereby precisely measuring a current leaking from an inverter-driven load device over a wide range of frequencies.

Insulation deterioration diagnosis apparatus

An optical encoder for measuring a relative movement of a first scale plate and a second scale plate, comprises: a light source; a first scale plate which converts light from the light source into a cyclic light quantity distribution; a second scale plate which cyclically makes spatial modulation on the light beams from the first scale plate; a third scale plate having slits which allow the light beams from the second scale plate to pass therethrough; and a light-receiving element which receives the light beams from the third scale plate; a lens which converts light from the light source into substantially parallel light beams; and an optic array which converges or diffuses light beams in the direction of periodic change and generates a cyclic light quantity distribution on the first scale plate.

Optical encoder applying substantially parallel light beams and three periodic optical elements

In an optical encoder comprising an optical scale in which a light transmission portion and a light non-transparent portion are arranged and an output pattern obtained by emitting an incident light functions as an optical code, a light source portion and a light detecting portion, the light non-transparent portion is constituted of at least one pair of inclined surfaces which are opposed in such a manner as to become farther away from each other towards the side where the incident light enters and set so that an incident angle of the optical axis of the incident light from the light source should not be smaller than a critical angle of incidence, and the light non-transparent portion is constructed so that the incident light which enters one inclined surface should be totally reflected thereon to enter the other inclined surface and then at least part of the incident light should be reflected on the other inclined surface, and a reflected light which is reflected on the other inclined surface should not enter a light emitting portion of the light source and a reflecting portion around the light emitting portion.

Optical encoder having a no track portion of an optical scale being placed at a position symmetrical to a light non-transparent portion within an irradiation region of incident light

An optical encoder includes an incoherent light source; a first grating, which is an amplitude grating having a first grating period, for spatial amplitude modulation of the incoherent light from the light source; a second grating, which is a phase grating having a second grating period, for spatial phase modulation of light from the first grating; a third grating, which is an amplitude grating having a third grating period, for spatial amplitude modulation of light from the second grating; and a light detecting element for detecting light from the third grating. The encoder detects relative displacement between the respective gratings. The optical transfer function from the light source to the light detecting element is enhanced, and the efficiency in utilizing light is improved.

Optical encoder

An optical encoder includes: a rotary slit plate having a rotation angle detection track including an optical slit; a light source for applying light to the optical slit; light detecting elements for rotation angle detection and arranged at positions to which light emitted from the light source is applied to the optical slit, to detect the light emitted from the light source and passing through the optical slit; and light detecting elements for light amount monitoring arranged at locations on a circumference in corresponding relationship with positions to which light emitted from the light source is applied to the optical slit, to detect the light emitted from the light source and passing through the optical slit. The light detecting elements for light amount monitoring have an angular width that is an integer multiple of the angular interval of the light intensity distribution on surfaces of the light detecting elements for light amount monitoring.

Optical rotary encoder

Optical encoder with reduced reflected light error having a light non-transparent portion with inclined surfaces

An optical rotary encoder for acquiring rotation information regarding a shaft includes a light source located on or in the vicinity of the axis of rotation of the shaft for emitting light rays and a code wheel mounted on the shaft for rotation about the axis of rotation. The code wheel has a plurality of alternating light transmissive and non-light transmissive areas in a circumferential direction. A reflector is spaced a distance from the code wheel for reflecting the light rays emitted from the light source so that they are turned into a parallel beam of light. The parallel beam of light illuminates the light transmissive areas of the code wheel so that light passing through the light transmissive areas is directed toward a peripheral region of the light source. The encoder also includes one or more light-detecting element for detecting the light passing through the light transmissive areas.

An optical distance sensor includes a first substrate provided with a light emitting element and a light detecting element, a one-piece optical structure body on a second substrate, the optical structure body having optical elements for converging incident light in a direction parallel to a surface of the second substrate and for converging an outgoing light beam from the light emitting element and a light beam reflected by an object in the direction parallel to the surface of the second substrate, and lenses for converging incident light in a direction perpendicular to the surface of the second substrate and for converging the outgoing light beam from the light emitting element and the light beam reflected by the object in the direction perpendicular to the surface of the second substrate, respectively.

Optical distance sensor

A photoelectric rotary encoder includes a light source that emits a light beam, a returning section that returns the emitted light beam to a direction opposite to an emitting direction of the beam, and a photodetector that is disposed on a substrate on which the light source is disposed and that detects the returned light beam via a disk having a detection pattern section. The photoelectric rotary encoder detects rotational displacement of the disk based on the detected returned light beam. In this photoelectric rotary encoder, an optical element that lets a stray beam component of the light beam from the light source escape via a side surface of the optical element, is disposed in front of the substrate on which the light source and the photodetector are disposed. The optical element covers the substrate and integrates the optical element and the substrate.

Photoelectric rotary encoder

A scale generates a periodic light-intensity distribution pattern having a pitch upon irradiation by emission light from a light source. Light-detecting element groups are shifted relative to the scale to generate phase signals having fixed phase differences. Light-detecting elements are adjacently positioned to have the same phase to form each light-detecting element group. Area centers of gravity on a phase axis of the light-detecting element groups having a fixed phase difference are made coincident with each other.

Phase-shift photoelectric encoder

A sensor head includes a first substrate provided with a light emitting element and a light detecting element, a one-piece optical structure body on a second substrate, the optical structure body having optical elements for converging incident light in a direction parallel to a surface of the second substrate and for converging an outgoing beam from the light emitting element and a light beam reflected by an object in the direction parallel to the surface of the second substrate, and lenses for converging incident light in a direction perpendicular to the surface of the second substrate and for converging the outgoing beam from the light emitting element and the light beam reflected by the object in the direction perpendicular to the surface of the second substrate, respectively.

Sensor head

An optical distance sensor is provided with a substrate on which a light emitting element and a light detecting element are disposed, and a single optical structure including a first converging mechanism for converging a light beam emitted from the light emitting element, a second converging mechanism for converging a light beam reflected by an object at a distance to be measured, and a reflecting mechanism for deflecting the light beam reflected by the object twice.

A detecting unit provided with an optical system is disposed away from a control unit formed by an electric circuit and an optical transmission/receiving means, and the detecting unit and the control unit are coupled through a transmission optical fiber. The control unit transmits to the detecting unit through the optical fiber a light wave which was subjected to the intensity modulation by a sinusoidal wave of a predetermined frequency. The transmitted light wave is branched into at least two branched optical paths within the detecting unit thereby to perform the phase modulation as to the respective light waves. The light waves passed through the respective branched optical paths are subjected to the phase modulation by the sinusoidal waves which differ in phase 1/4 period by 1/4 period from one another according to a position on a straight line or a rotation angle of a subject to be detected. Then, the light waves thus subjected to the intensity modulation are coupled to a single transmission optical fiber through the branched optical paths and transmitted to the control unit through the transmission optical fiber. In the control unit, the modulated light wave is received and subjected to the phase detection, thereby to calculate and output the position and the rotation angle in accordance with the phase modulation amount of the received light wave.

A radiation detector obtains radiation information by detecting a light pulse occurred in response to a radiation in a scintillation fiber at one end or opposite ends of the scintillation fiber. The scintillation fiber is surrounded by a scattering member which emits an electron by interaction with the radiation.

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Tokyo, Japan

Toru Oka