[Amps] Arcing

rlm 2 at vc.net
Sat Mar 8 03:10:55 EST 2003


>...
Tom Rauch:
>> >As you learned, an open termination on a current transformer can produce
>> >some large voltages!! But no more that the turns ratio of the transformer
>> >and operating voltage would indicate.
>>
Me:
>> **  it is my opinion that the counter-EMF spike can be many times the
>> rated primary operating V.
>
>Yes, Rich, this has always been my understanding also. In fact, it's
>difficult to define the extent of the CT primary, to determine the voltage.
>The cable may connect from one phase of a power transformer to a bus feeder
>breaker 300 ft away. It seems there's always more to things than first meets
>the eye. I once listened to a man lecture on "motor stator insulation" for 2
>solid days...and he kept my attention! It seemed he lived for motor stators!
>A life like that is for people who don't know how to fish.
>
>Jeff
>
When DC current abruptly stops, the potential for reverse potential is 
impressive.  I've measured 400v-pk with an o'scope across 24vdc relay 
coils.  I would like to hear Mr. Rauch's explanation of why the operating 
voltage limits reverse potential.

Ever tried fishin' in the amazon?  I understand there's a eel-like fish 
named Electrophorus electricus in there that can do 1kV @ 1A when full 
grown to c. 6-ft.  Presumably, a carbon-fiber fishing rod is not a wise 
choice

cheerz, Jeff


-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
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