鋼索の無速度電磁探傷

抄録

the search coil.This semiconductor device is somewhat similar to well known magneto-electric converting devices, except that the sensitivity of this device is several hundred times greater than that of them.
The most significant feature of the new system is its independency of the sensitivity on the rope speed, which substantiated the inspection virtually at any speed including motionless state.
Several units of the device, whose number is consequential to its physical dimensions and also to the inherent directional sensitivity, are laid on a pair of split bobbin to encircle the rope simultaneously at a close two sections to form a twin annular detector assembly.
Serial or cummulative connection of all the units in one section covers the effect of lateral vibration of the rope, and the differential connection between the both halves of the twin results in a satisfactory enhancement of overall noise immunity.
The output voltage ranges approximately ten times greater than the e.m.f.on the conventional search coils at a pertinent magnetization, and may be fed into an appropriate differential amplifier for following signal processing.
For general inspection, the number of the units in each half should not be consistent with the number of strands in the rope in order to reduce the periodical noise caused by the inevitable periodic change in radial clearance between the relief of rope surface and the annular detector assembly while the rope passes.
This system with another version of the detector assembly may also be applied to measuring the let out length of a rope, determining the elongation and examining the uniformity of rope strand, in which assembly the number of the units in each half should be consistent with the number of strands.