Circularly magnetized non-contact torque and power sensor and method for measuring torque and power using same

(57) the torque and the power sensing device (2) which supplies the output signal which shows the power transmitted by the torque added to the torque component (8) which carries out summary rotation, or this torque component (8), It has a magnetic-field-modulation means (25) to modulate a magnetic field the cycle which shows the revolving speed of the magnetoelasticity activity element (4) which generates the magnetic field which changes in connection with the added torque, and a torque component. Magnetic field vector sensors (6), such as a Hall effect sensor, detect the amplitude of the modulated magnetic field which supplies the output signal which shows the torque added to the component (8) to rotate to alignment. Or a coil-like magnetic field vector sensor detects the amplitude of the rate of a variation per hour of the modulated magnetic field which supplies the output signal which shows the power transmitted by the component (8) to rotate to alignment. A magnetic-field-modulation means (25) equips a circumferential side with at least one ring which has the projection form arranged at intervals of equal a gear-like tooth etc.