Current transformer

Sylvia Else · 2015-12-08T04:30:53+00:00

I was looking for a cheap clip-on current transformer to use to monitor my power usage, and I found this: which I guessed (correctly) was a current transformer. I that have no intention of using it with Efergy's products, since they don't seem concerned about the voltage, which can vary somewhat from nominal, and are certainly unconcerned about the phase. Anyway, when it arrived, I noticed that it has a three contact plug which made me wonder what was actually inside the sensor. It came apart easily enough, and I inferred the circuit appended to the end of this posting. Note that the inductor on the AC current side is really just the wire carrying the current to be sensed. I supposed that the 220 ohm resistor was the required load, but when I tested the device, I found that the output was clearly being clipped by the diodes and 33 ohm resistor. In fact, a resistance of just a few ohms will be required to get a linear output up to the rated 70 amps. It looks like the idea behind having the 33 ohm resistor there is that the rest of the electronics can determine when the sensor is overloaded by the resulting asymmetry in output. I can't see what output B is for. Any thoughts? Version 4 SHEET 1 880 680 WIRE 16 16 -96 16 WIRE 80 16 16 16 WIRE 128 16 80 16 WIRE 192 16 128 16 WIRE 256 16 192 16 WIRE 80 32 80 16 WIRE 192 80 192 16 WIRE 256 80 256 16 WIRE 448 80 368 80 WIRE -64 112 -96 112 WIRE 16 112 16 16 WIRE 80 128 80 112 WIRE 128 128 128 16 WIRE 288 160 288 80 WIRE 304 160 304 80 WIRE 320 160 320 80 WIRE 448 160 368 160 WIRE 80 224 80 192 WIRE 80 224 -96 224 WIRE 128 224 128 192 WIRE 128 224 80 224 WIRE 192 224 192 160 WIRE 192 224 128 224 WIRE 256 224 256 160 WIRE 256 224 192 224 FLAG -96 16 A FLAG -96 112 B FLAG -96 224 C SYMBOL ind 240 64 R0 SYMATTR InstName L1 SYMBOL diode 112 128 R0 SYMATTR InstName D1 SYMBOL diode 96 192 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D2 SYMBOL res 64 16 R0 WINDOW 0 30 49 Left 2 WINDOW 3 26 82 Left 2...

Dec 08, 2015 42 Replies

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Jeff Liebermann 10 years ago

Cheap? Plenty on eBay for much less money.

Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

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Robert Baer 10 years ago

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tabbypurr 10 years ago

thank you :)

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