Eddy current strength?

[Buz]

n/t

 

[Anonymous]

n/t

 

[Kev]

Hi Wyndham,
The way I understand it, and it could be a little off the mark? The rotation of the eddy currents are changing direction twice every pulse. As the current builds in the coil the eddys rotate in one direction, and when the coil current is cutoff the eddys rotate in the counter direction. This is why it is important to reach steady state current in the coil before switching the current off, then the eddys will have died down in the target, since the di/dt is near enough to zero, and as Al has stated the eddys are induced only when the flux is changing.

If the coil current is switched off before steady state, some of the energy generated from the collapse of the field will be expended reversing the direction of the eddy currents, and will be subtracted from the total return signal.

Therefore, the greatest current strength induced in a target will come from collapsing the field to zero in the shortest possible time after the eddys generated in the target while the field was being generated have died down to zero.

Cheers
Kev.

 

[Prospector Al]

Hi Kev,

"Therefore, the greatest current strength..."

You have stated in one elegant sentence what I tried to prove with a bunch of equatioans...

Good work.

P. Al

 

[wyndham]

Thanks I'm getting a good picture of the process. Wyndham

 

[Kev]

n/t