Abstract: Disclosed are a composite separation membrane structure for a gas sensor for real-time monitoring of degradation of insulating oil of a power transformer, a gas sensor apparatus including the same, and a method and an apparatus for measuring gas concentration using the same. It is possible to locally diagnose whether there is a fault in the power transformer and what kind of fault occurs where in the power transformer by quantitatively measuring the concentration of several gases dissolved in the insulating oil in real time. As a result, breakdown of the power transformer may be prevented and remaining service life of the insulating oil in the power transformer may be predicted.

Abstract: Disclosed are a composite separation membrane structure for a gas sensor for real-time monitoring of degradation of insulating oil of a power transformer, a gas sensor apparatus including the same, and a method and an apparatus for measuring gas concentration using the same. It is possible to locally diagnose whether there is a fault in the power transformer and what kind of fault occurs where in the power transformer by quantitatively measuring the concentration of several gases dissolved in the insulating oil in real time. As a result, breakdown of the power transformer may be prevented and remaining service life of the insulating oil in the power transformer may be predicted.

Abstract: There is provided a bearingless step motor in which a rotating shaft can rotate while rising from a main body by a magnetic force without using a mechanical bearing. The bearingless step motor comprises a stator including stator cores having winding portions and a rotor including a rotating shaft and rotor cores. The rotor rotates by a magnetic interaction between the rotor cores and the stator cores. A first permanent magnet is mounted to the rotor and a second permanent magnet is mounted to the stator. The first permanent magnet and the second permanent magnet are arranged so that a repulsive force is generated between magnetic poles. There is little power consumption for raising the rotating shaft and a complicated system for controlling the rise of the rotating shaft is unnecessary. Thus, the motor can be manufactured with a light and compact structure.

Abstract: There is provided a coating material having heat and abrasion resistance and low friction characteristics, as well as a method of utilizing the same. The coating material comprises 20 to 40 wt % Cr2O3, 40 to 60 wt % binder, 10 to 20 wt % WS2, and 10 to 20 wt % Ag. The binder comprises 60 to 80 wt % Ni and 20 to 40 wt % Cr. The binder may further comprise above 0 to 10 wt % Al. The coating method comprises the steps of pulverizing the coating material, pulverizing a binder, applying the pulverized binder to a surface of a workpiece to form a first layer, applying the pulverized coating material to the first layer to form a second layer, and grinding and polishing the surface of the second layer.

Abstract: There is provided a method and apparatus for monitoring oil deterioration in real time. The method includes the steps of radiating light into an oil medium and measuring light intensities at red, green and blue wavelength ranges of the light after passing through a certain thickness of the oil. A ratio of the light intensity at the red wavelength range to the light intensity at the green wavelength range is computed by using the measured light intensities. These steps are repeated to monitor a change in the above ratio value in real time of oil use.

Abstract: There is provided a bearingless step motor in which a rotating shaft can rotate while rising from a main body by a magnetic force without using a mechanical bearing. The bearingless step motor comprises a stator including stator cores having winding portions and a rotor including a rotating shaft and rotor cores. The rotor rotates by a magnetic interaction between the rotor cores and the stator cores. A first permanent magnet is mounted to the rotor and a second permanent magnet is mounted to the stator. The first permanent magnet and the second permanent magnet are arranged so that a repulsive force is generated between magnetic poles. There is little power consumption for raising the rotating shaft and a complicated system for controlling the rise of the rotating shaft is unnecessary. Thus, the motor can be manufactured with a light and compact structure.

Abstract: There is provided a method and a device of monitoring oil oxidation in real time. The method of the present invention comprises the steps of: irradiating ultraviolet light into oil to be monitored; measuring fluorescence emission intensity of the oil in red, green and blue wavelength bands; determining one value measured in a relatively long wavelength band and the other value measured in a relatively short wavelength band among the fluorescence emission intensity measured in the red, green and blue wavelength bands; calculating a fluorescence emission ratio which is defined as a ratio of the value measured in the relatively long wavelength band to the value measured in the relatively short wavelength band; and monitoring a change in the fluorescence emission ratio. It is then determined whether the fluorescence emission ratio reaches a predetermined critical magnitude. When the fluorescence emission ratio reaches the critical magnitude, the necessity of replacing the oil with new one is indicated.

Abstract: There is provided a method and apparatus for monitoring oil deterioration in real time. The method includes the steps of radiating light into an oil medium and measuring light intensities at red, green and blue wavelength ranges of the light after passing through a certain thickness of the oil. A ratio of the light intensity at the red wavelength range to the light intensity at the green wavelength range is computed by using the measured light intensities. These steps are repeated to monitor a change in the above ratio value in real time of oil use.

Abstract: There is provided a method and a device of monitoring oil oxidation in real time. The method of the present invention comprises the steps of: irradiating ultraviolet light into oil to be monitored; measuring fluorescence emission intensity of the oil in red, green and blue wavelength bands; determining one value measured in a relatively long wavelength band and the other value measured in a relatively short wavelength band among the fluorescence emission intensity measured in the red, green and blue wavelength bands; calculating a fluorescence emission ratio which is defined as a ratio of the value measured in the relatively long wavelength band to the value measured in the relatively short wavelength band; and monitoring a change in the fluorescence emission ratio. It is then determined whether the fluorescence emission ratio reaches a predetermined critical magnitude. When the fluorescence emission ratio reaches the critical magnitude, the necessity of replacing the oil with new one is indicated.

Abstract: There is provided a coating material having heat and abrasion resistance and low friction characteristics, as well as a method of utilizing the same. The coating material comprises 20 to 40 wt % Cr2O3, 40 to 60 wt % binder, 10 to 20 wt % WS2, and 10 to 20 wt % Ag. The binder comprises 60 to 80 wt % Ni and 20 to 40 wt % Cr. The binder may further comprise above 0 to 10 wt % Al. The coating method comprises the steps of pulverizing the coating material, pulverizing a binder, applying the pulverized binder to a surface of a workpiece to form a first layer, applying the pulverized coating material to the first layer to form a second layer, and grinding and polishing the surface of the second layer.

Abstract: An apparatus for measuring oil oxidation is capable of being mounted to mechanical devices for detecting power of fluorescent light reflected from oil in real time as an indication of the oil oxidation. A plurality of first optical fibers are connected to a light-emitting member for introducing the light into oil at different incidence points. A plurality of light-reflecting mirrors are immersed in the oil and disposed opposite to the incidence points. The light-reflecting mirrors are located at different distances from the incidence points. A plurality of second optical fibers are connected to the incidence points, respectively. A plurality of light-receiving members are connected to the second optical fibers for receiving the light and outputting the signals corresponding to the received light.

Abstract: An apparatus for measuring oil oxidation is capable of being mounted to mechanical devices for detecting power of fluorescent light reflected from oil in real time as an indication of the oil oxidation. A plurality of first optical fibers are connected to a light-emitting member for introducing the light into oil at different incidence points. A plurality of light-reflecting mirrors are immersed in the oil and disposed opposite to the incidence points. The light-reflecting mirrors are located at different distances from the incidence points. A plurality of second optical fibers are connected to the incidence points, respectively. A plurality of light-receiving members are connected to the second optical fibers for receiving the light and outputting the signals corresponding to the received light.

Abstract: An apparatus for measuring soot content in diesel engine oil in real time comprises an optical rod capable of transmitting light and having a boundary surface adapted to be in contact with the diesel engine oil and first and second end portions, a light-emitting portion, and a first optical fiber connected to the light-emitting means. The first optical fiber is adapted to transmit light from the light-emitting means to the first end portion of the optical rod in an aperture angle of the optical fiber to the boundary surface. The apparatus also comprises a light-receiving portion adapted to receive light from the optical rod and output a signal corresponding to the received light power. The refractive index of the optical rod is larger than the refractive index of the diesel engine oil. The aperture angle of the optical fiber is equal to or larger than a critical angle reduced to air at which the light is totally reflected by the boundary surface.

Abstract: An apparatus for measuring soot content in diesel engine oil in real time comprises an optical rod capable of transmitting light and having a boundary surface adapted to be in contact with the diesel engine oil and first and second end portions, a light-emitting portion, and a first optical fiber connected to the light-emitting means. The first optical fiber is adapted to transmit light from the light-emitting means to the first end portion of the optical rod in an aperture angle of the optical fiber to the boundary surface. The apparatus also comprises a light-receiving portion adapted to receive light from the optical rod and output a signal corresponding to the received light power. The refractive index of the optical rod is larger than the refractive index of the diesel engine oil. The aperture angle of the optical fiber is equal to or larger than a critical angle reduced to air at which the light is totally reflected by the boundary surface.