| 摘要 |
<p>Sheet metal eddy current principle spot weld quality checking device comprises a coil system including a prim. and a sec. coil placed above the weld zone. A suitable frequency sinusoidal a.c. current is passed through the prim. coil. This sets up a magnetic pulsating field which produces eddy currents in the weld zone generating in turn a current in the sec. measuring coil which is passed into a resonance amplifier, rectified and then fed into a display instrument. The two soils are pref. enclosed in a ferrite shell core which is mounted in a plastic handle holder. The eddy currents are displaced pref. on an oscillograph screen. The system permist the non-destructive routine testing of spot welds.</p> |
