Quality and Inspection Process Knowledge
Quality and Inspection Services
Eddy current is used to detect surface cracks, pits, subsurface
cracks, corrosion on inner surfaces, and to determine alloy and heat-treat
A wide variety of eddy current test instruments are available.
The eddy current test instrument performs three basic functions: generating,
receiving, and displaying. The generating portion of the unit provides an
alternating current to the test coil. The receiving section processes the signal
from the test coil to the required form and amplitude for display. Instrument
outputs or displays consist of a variety of visual, audible, storage, or
transfer techniques utilizing meters, video displays, chart recorders, alarms,
magnetic tape, computers, and electrical or electronic relays.
Principles of Operations: Eddy currents are induced in a
test article when an alternating current is applied to a test coil (probe). The
alternating current in the coil induces an alternating magnetic field in the
article which causes eddy currents to flow in the article.
Generating an Eddy Current
Detecting an Eddy Current