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Technical Discussions
Alan
Sales
GEIT, Hong Kong, China, Joined Jan 2008, 1

Alan

Sales
GEIT,
Hong Kong, China,
Joined Jan 2008
1
05:08 Jan-02-2008
About pulsed eddy current testing

What is principle of pulsed eddy current?
What are the differences to the traditional method?


 
 Reply 
 
Catalin Mandache
Catalin Mandache
05:12 Jan-03-2008
Re: About pulsed eddy current testing
Hi Alan,

Here are the main differences (there are many others):
- Pulsed (or Transient) eddy current uses a square wave or step function excitation instead of a sinusoidal one, as used for conventional eddy current testing.
- The received pulsed eddy current signal response is usually represented in the time domain (as with ultrasonic waves testing); conventional eddy current instruments use the impedance plane diagram for signal representation.

The biggest advantage of pulsed eddy current testing comes from deeper penetrability than in conventional technique. This is due mainly to the rich frequency content in a square wave, but also to the large diameter types of excitation coils used.

Some of these differences are discussed in an article right on this site:
http://www.ndt.net/article/v10n06/mandache/mandache.htm

----------- Start Original Message -----------
: What is principle of pulsed eddy current?
: What are the differences to the traditional method?
------------ End Original Message ------------




 
 Reply 
 
Michael Moles †2014 *1948
, Joined ,
03:48 Jan-03-2008
Re: About pulsed eddy current testing
----------- Start Original Message -----------
: Hi Alan,
: Here are the main differences (there are many others):
: - Pulsed (or Transient) eddy current uses a square wave or step function excitation instead of a sinusoidal one, as used for conventional eddy current testing.
: - The received pulsed eddy current signal response is usually represented in the time domain (as with ultrasonic waves testing); conventional eddy current instruments use the impedance plane diagram for signal representation.
: The biggest advantage of pulsed eddy current testing comes from deeper penetrability than in conventional technique. This is due mainly to the rich frequency content in a square wave, but also to the large diameter types of excitation coils used.
: Some of these differences are discussed in an article right on this site:
: http://www.ndt.net/article/v10n06/mandache/mandache.htm
: : What is principle of pulsed eddy current?
: : What are the differences to the traditional method?
------------ End Original Message ------------

Alan:

Try the following web site: http://www.ndt-ed.org/EducationResources/CommunityCollege/EddyCurrents/AdvancedTechniques/background.htm. This gives a good outline of pulsed eddy currents.

Michael



 
 Reply 
 
Alan
Alan
02:43 Jan-08-2008
Re: About pulsed eddy current testing
Hello Michael,

Thank you!
The web is so useful.
I am new in NDT. It is so good to find friends here.
=]

----------- Start Original Message -----------
: Hi Alan,
: Here are the main differences (there are many others):
: - Pulsed (or Transient) eddy current uses a square wave or step function excitation instead of a sinusoidal one, as used for conventional eddy current testing.
: - The received pulsed eddy current signal response is usually represented in the time domain (as with ultrasonic waves testing); conventional eddy current instruments use the impedance plane diagram for signal representation.
: The biggest advantage of pulsed eddy current testing comes from deeper penetrability than in conventional technique. This is due mainly to the rich frequency content in a square wave, but also to the large diameter types of excitation coils used.
: Some of these differences are discussed in an article right on this site:
: http://www.ndt.net/article/v10n06/mandache/mandache.htm
: : What is principle of pulsed eddy current?
: : What are the differences to the traditional method?
------------ End Original Message ------------




 
 Reply 
 
Alan
Alan
02:47 Jan-08-2008
Re: About pulsed eddy current testing
Hi Catalin,

Thank you for your information.
You must be a expert in ET.

----------- Start Original Message -----------
: Hi Alan,
: Here are the main differences (there are many others):
: - Pulsed (or Transient) eddy current uses a square wave or step function excitation instead of a sinusoidal one, as used for conventional eddy current testing.
: - The received pulsed eddy current signal response is usually represented in the time domain (as with ultrasonic waves testing); conventional eddy current instruments use the impedance plane diagram for signal representation.
: The biggest advantage of pulsed eddy current testing comes from deeper penetrability than in conventional technique. This is due mainly to the rich frequency content in a square wave, but also to the large diameter types of excitation coils used.
: Some of these differences are discussed in an article right on this site:
: http://www.ndt.net/article/v10n06/mandache/mandache.htm
: : What is principle of pulsed eddy current?
: : What are the differences to the traditional method?
------------ End Original Message ------------




 
 Reply 
 
Riccardo Scottini
Riccardo Scottini
04:39 Jan-11-2008
Re: About pulsed eddy current testing
Hi Alan,

Our Pulsed Eddy Current equipment is called RTD-INCOTEST, where INCOTEST is an acronym for INsulated COmponent TESTing. The principle of pulsed Eddy Current is that once a stable magnetic field is created with a sending coil (DC current) in the carbon steel plate under examination. The sending circuit is opened and the receiving coil record the signal of the Eddy Currents induced in the base material during this "transitorium". No Eddy Current is induced when the magnetic field is constant. These are induced when the Magnetic Field changes therefore during the “transitorium”.
The technique does not need any contact or special cleaning and may is efficient through insulation and weather proofing even of Galvanised cladding or through fire proofing and coating. The equipment needs the object under examination to be ferromagnetic, therefore Carbon Steel or Low Alloy Carbon Steel.
The main difference with traditional Eddy Current Methods is that mostly they measures continuously and they are mainly performed on not Ferro materials and INCOTEST needs a ferro base material and it is perform with steady measurement because on each measurement position the induced DC magnetic field must first get uniform and constant, once this condition is reached (some ms) the equipment “listen” to the transitorium (some ms) and only after that the probe may be replaced to the next position. Other difference is that INCOTEST gives Average Wall Thickness values in a lift-off range up to 200mm and may inspect WT up to 65mm.

I linked our INCOTEST site where you may find more information also regarding the technology main applications.

Any question… feel free to contact me.
Regards
Riccardo




 
 Reply 
 
karthikeyan.J
karthikeyan.J
05:29 Jan-26-2008
Re: About pulsed eddy current testing

What is principle of pulsed eddy current?
What are the differences to the traditional method?
what is the difference of the eddy current from other NDT methods?


 
 Reply 
 

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