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|Posté le: Jeu 30 Nov - 13:30 (2017) Sujet du message: Current Transformer Questions
I'm working on a project which in its final form will need to be connected directly to a power line between 7kv-100kv. Already know I need to use a current transformer, but after looking transformer portion of AAC's, my application is a bit different and was wondering if anyone could steer me in the right direction. Not looking for circuit designs, just knowledge.
I intend to use the current transformer to power a device which requires only 3Vdc and about 20-40ma when active, and 0ma when inactive. Device will be inactive 99.9% of the time which give me concern about it building up a crazy voltage across the secondary when it is inactive. Luckily, the other components which I intend to drive are not ICs and only 1 concerns me regarding the voltage builing up, the one component which is 1.5-3Vdc.
When the current is generated by the CT, I know there will be no guarantee what the voltage will be but obviously I will have a ton of current at my disposal.
Since I have no ground reference nor any other sources, I am rather limited in what I can do because I haven't ever dealt with a situation like this.
Old school AC/DC transforming comes into mind with some diodes, and a cap/zener to limit the voltage, but am I going to be dumping around 5 amps when not in use? I really can't have that. Don't have the room to disipate that much heat. At most, I'd like to disipate no more than 100mW.
I need to come up with a real cheap, out of the box solution for this if possible. No component that would cost more than 10-20 cents in bulk.
I didn't find the right solution from the Internet.
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