[TenTec] Induction Field [WAS - PS grounding]

[tongaloa]

Pete-

OK
But I still don't understand how enough EMF can be generated to cause 
problems.

I'm probably confused by the ratings they use on MRI machines.
When I'm in the MRI machine and it's a 0.5T field (according to the
operator) does he really mean 0.5T/s or does he mean the maximum field 
strength is 0.5T
which at MRI operating frequencies is lots more than the 0.02T field 
strength at a meter
from a pretty good sized, real, lightning bolt.

If the lightning bolt takes 10 microseconds to go from 'small' to 'full' 
current then
it's roughly 200T/s which would produce a LOT more EMF than a 0.5T/s MRI...
I don't know MRI operating frequency but at 500kHz it would be roughly 
500T/s
if the 0.5T (operator number) is the max. (I think 500kHz is abotu 
right??? Any MRI
ops out there?)

I didn't croak in the MRI machine and I was there for an hour ;-)

73,
-Bob




ac5e at comcast.net wrote:

>Bob, an induction field is an induced current, or voltage, resulting from current flow. Lotsa current equals lotsa induction field. Which, according to the local street preacher, is often followed by checking out a harp and wings. 
>
>The human body is essentially a high resistance one turn inductor. In lab testing during the 1950's more than 5 Kv at 10 A was measured in a cadaver near a lab lightning stroke. And lab lightning is a very mild cousin to the wild lightning generated in a thunderstorm. Do not put your unshielded self or anything you value near anything that will attract the wild stuff. 
>
>And I forgot who asked, but yes, your rotor cables need to be lightning arrestored, grounded, and anything else that can be done to keep the big sparks away. 
>
>73  Pete Allen AC5E
>
>
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