Re: Lightning strikes monitor (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Mon, 10 Sep 2007 08:47:13 -0400
From: Russell L Thornton <Russell.L.Thornton@xxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: Lightning strikes monitor

Bert,
Just for your info, here at Cape Canaveral we get strikes that measure 
greater than 100 kamps.
Russell

To:
tesla@xxxxxxxxxx
Subject:
Re: Lightning strikes monitor (fwd)
---------- Forwarded message ----------
Date: Wed, 05 Sep 2007 13:34:19 -0500
From: Bert Hickman <bert.hickman@xxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Lightning strikes monitor (fwd)

Hi Peter,

Sounds interesting! If you do plan to use a Rogowski coil to measure the 
lightning discharge currents, make sure to provide LOTS of clearance 
between the lightning conductor and the Rogowski toroid. The combination 
of very high di/dt (typically 5 - 16 kA/us) and unavoidable path 
inductance can cause very high transient voltages to be developed on 
even a robust, well-earthed conductor. Also, try to locate the Rogowski 
coil close to the point where the conductor is physically grounded to 
minimize voltage from inductive transients. You may also need to add 
electrostatic shielding on the coil itself. I'll forward you some 
additional information (off list) that you may find useful.

BTW, during some recent storms, three holes, about 6 feet apart, and 
each about 4" in diameter and 6" deep were created in a neighbors yard. 
These were from a sequence of three lightning bolts that occurred within 
a fraction of a second. Apparently the high wind during the storm was 
sufficient to blow plasma from the previous strike laterally between 
hits. Mud was blown onto nearby houses, and cable TV was killed on the 
block for several days.

Play VERY safely,

Bert