GEAR MEASURING MECHANICAL STRESSES IN METAL ARTICLES Russian patent published in 1997 - IPC

FIELD: nondestructive testing by electromagnetic fields. SUBSTANCE: gear measuring mechanical stresses in metal articles has A.C. generator, converter incorporating cruciform magnetic circuit with excitation and measurement windings, amplifier, detector and indicator connected in series. Gear is fitted with mixer placed between measurement winding and input of amplifier, three phase inverters connected to output of generator and three amplifiers. First amplifier is placed between output of phase inverter and second input of mixer, second amplifier is placed between output of phase inverter and second input of detector, third amplifier is placed between output of phase inverter and third input of mixer. Gear is also provided with band-pass filter placed between amplifier and first input of detector and attenuator placed between output of detector and input of indicator. EFFECT: increased precision and expanded measurement range of gear. 1 dwg