Issues with SCT-013-030

Hey there,

I decided to do some power consumption measuring this week. Unfortunately, the SCT-013-000 was out of stock at my local supplier, but they fortunately still had the SCT-013-030. 

I left out the burden resistor and connected everything similar to https://roysoala.files.wordpress.com/2012/04/ardu_ct_ac.jpg?w=700
While the voltage monitoring works perfectly, the current monitoring doesn't work at all. 

Some observations:

a) only gnd and + are connected on the 3,5mm connectors
b) my multimeter tells me that there is continuity / contact between gnd and + 
c) there is a wire between the coil and the cable on the lower one of my 2 CTs (see picture). I'm assuming it shouldn't be there? 

So. Connecting + and gnd to my multimeter (which is in VAC mode), I don't get any output at all. (Tested for various devices). Any ideas?

Cheers,

th0br0

Robert Wall's picture

Re: Issues with SCT-013-030

I don't know what that 3rd party site recommends.

"gnd and + are connected on the 3,5mm connectors"
Do you mean "Sleeve" and "Tip"? If you do, that is correct. The cable screen is normally not connected.

"c) there is a wire between the coil and the cable"
I don't understand what you are trying to say there. The two ends of the secondary winding should connect to the plug tip and sleeve respectively via the two cores of the cable. The internal burden resistor should connect in parallel with the secondary winding.

If you need connection data for the SCT-013-030, it is identical to the -000 in the report under CT sensors - Introduction in the Building Blocks section here, except that the internal burden resistor replaces the two diodes present in the -000.

Also, as you note, the output is a voltage rather than a current. Are you installing your CT as described in "CT Installation" (also in the same Building Blocks section).

th0br0's picture

Re: Issues with SCT-013-030

Apologies, it was indeed a case of bad installation. Both CTs seem to work fine.

Regarding c) see the image... (unsharp, I know :/) the lower one has 2 unshielded copper wires while the other doesn't. The point where the upper wire is connected to the board is different as well...

And I referred to gnd and + as the 3,5mm connectors I've got here have got 3 poles even though only 2 are connected.

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