So I recently bought 3 current transformers with the goal to measure the current of 3 washing machines. All I want to measure is if the machines are running or not so accuracy isn't really a concern. Now I ordered them a bit hasty and didn't think of the actual working logic of these guys. From what I read, I thought I can just clamp them around a power cable and read the current.
Which apparently is not the case because I can only measure one phase with a CT as far as I understand. I live in a country with a 3 phase system and I don't understand that much about alternating current. I tried to read into this 3 phase system but its quite a bit over my head.
Now from what I think I understand, this means if I clamp this around a standard power plug I wont get any output voltage because the phases cancel each other out and I don't get any magnetic field that the ct could sense, is that correct?
Question: Would it be possible to remove the outer isolation of a power cable and clamp the CT to just one of the three cables/phases? Or would they be too close and interfere and still cancel each other out? Or is it a stupid idea all together because I totally didn't get how this 3 phase alternating current system works?
This is the CT sensor I'm using: http://www.seeedstudio.com/depot/noninvasive-ac-current-sensor-30a-max-p-519.html Datasheet: http://garden.seeedstudio.com/images/b/bc/SCT013-030V.pdf