International School of Aerospace NDT Limited
Eddy Current Phase Analysis
(24 hour/3 day Course)
This course is designed for NDT technicians and engineers already practising eddy current inspection requiring a more in depth understanding of impedance plane analysis and involves both theoretical and practical applications allowing the student to gain experience in a wide variety of NDT inspection procedures using this method of NDT.
Ideally the candidate should have attained Level II in eddy current inspection prior to attending this course.
The course comprises:
- Review of basic eddy current theory.
- Basic test equipment.
- Generation of eddy currents.
- Magnetic field around ac coil.
- Calculations regarding the generation of eddy currents.
- Properties of eddy current flow.
- Standard depth of penetration.
- Depth of penetration in finite thickness samples.
- Standard phase lag.
- Phase lag in finite thickness of samples.
- Calculations regarding depth of penetration and phase lag.
- Electrical circuits.
- Introduction.
- Calculations regarding impedance.
- Simplified impedance diagrams.
- Bridge circuits description and typical example of test equipment.
- Resonance circuits.
- General impedance type of equipment.
- Multifrequency equipment.
- Calculations of impedance at resonance.
- Testing with surface probes.
- Types and sensitivity.
- Factors affecting sensitivity to defects.
- Effects of resistivity , permeability, thickness and frequency.
- Probe diameter.
- Definition of phase.
- Measuring resistivity, thickness and non-conducting/conducting layer on a conductor.
- Probe cable resonance.
- Eddy current signal characteristics.
- Coil impedance changes with other variables.
- Ferromagnetic indications, electrical resistivity geometry.
- Testing ferromagnetic materials.
- Factors affecting resistivity.
- Magentic hysterisis.
- Permeability.
- Factors affecting permeability.
All students are continually assessed during the course by homework and progress tests together with a theoretical end of course examination.
For further information please contact the Training Manager.