Abstract: The rotary transformer 5 includes a plate-shaped stator 51 having a coil arranged on one surface thereof, and a plate-shaped rotator 52 having a coil arranged on one surface thereof, in which the respective coil-arranged surfaces are disposed to face with each other so that signal transmission in a frequency range of 1 to 10 MHz is performed between the coils. The stator includes a substrate 512 on which a plurality of one-turn coils are formed into a concentric shape, and a supporting member 513. The rotator includes a substrate 522 on which one-turn coils 521 of same number are formed into a concentric shape, and a supporting member 523. Air or a material M which is an insulator and has a relative magnetic permeability substantially equal to 1 is lying between the substrate 512 and the supporting member 513, and between the substrate 522 and the supporting member 523.

Abstract: The rotary transformer 5 includes a plate-shaped stator 51 having a coil arranged on one surface thereof, and a plate-shaped rotator 52 having a coil arranged on one surface thereof, in which the respective coil-arranged surfaces are disposed to face with each other so that signal transmission in a frequency range of 1 to 10 MHz is performed between the coils. The stator includes a substrate 512 on which a plurality of one-turn coils are formed into a concentric shape, and a supporting member 513. The rotator includes a substrate 522 on which one-turn coils 521 of same number are formed into a concentric shape, and a supporting member 523. Air or a material M which is an insulator and has a relative magnetic permeability substantially equal to 1 is lying between the substrate 512 and the supporting member 513, and between the substrate 522 and the supporting member 523.

Abstract: A method for ultrasonically detecting flaws in a welded portion of a pipe by using an ultrasonic wave phased array probe having an array of a plurality of transducer elements for emitting and receiving ultrasonic wave beams, wherein at least one monitoring probe is located in the vicinity of the welded portion to receive the ultrasonic wave beam, whereby peak values of the ultrasonic wave beams are detected within a predetermined gate, a maximum peak value of the detected peak values is determined to determine a pilot beam having the maximum peak value, and effective beams which reach the portion of the welding portion to be tested are determined from the determined pilot beam.