Abstract: An instantaneous current and instantaneous voltage of a three-phase coil of a brushless DC motor are detected, and the internal condition of a compressor is predicted from these detection values. The prediction about the internal condition of the compressor is made in such a way that motor driving torque which is a parameter of a motor model is identified and poor lubrication, liquid compression or the like is predicted from this identified motor driving torque. This enables it to make, in real time, a failure forecast, failure diagnosis etc. on the compressor.

Abstract: An instantaneous current and instantaneous voltage of a three-phase coil of a brushless DC motor are detected, and the internal condition of a compressor is predicted from these detection values. The prediction about the internal condition of the compressor is made in such a way that motor driving torque which is a parameter of a motor model is identified and poor lubrication, liquid compression or the like is predicted from this identified motor driving torque. This enables it to make, in real time, a failure forecast, failure diagnosis etc. on the compressor.

Abstract: An automatic tube circumference scanning apparatus automatically performs inspections, repairs and other operation on a group of tubes arrayed in a narrow space and extending in horizontal directions. The apparatus includes an upper support/traverse section mounted on an upper tube in the group of tubes so as to be able to travel along a tube axis and to stop and grip the upper tube, a lower support/traverse section mounted on a lower tube so as to be able to travel, stop and grip the lower tube, a flexible rail extending vertically between the upper and lower support/traverse sections and fixed thereto, and a probe scanning section mounted on the flexible rail so as to be able to move up and down and which grips any arbitrary tube between the aforementioned upper and lower tubes for making a probe scan around such tube.

Abstract: An automated ultrasonic examination system for heat transfer tubes in a boiler makes it possible to perform ultrsonic examination from inside of the heat transfer tubes without necessitating the removal of scale from the outer surfaces of the boiler tubes by polishing and without necessitating access to places where manual measurements are difficult or impossible to make.