300 A current sensor CT

Hi, I m very happy with the <100 A current transformers form the openenergymonitor shop.

To measure the total power from a test field with small and middle scale wind turbines ( 5 - 75 kW)

I need a non invasive current transformer that can handle up to 300 Amps.

Has anyone some experience / suggestions?



Robert Wall's picture

Re: 300 A current sensor CT

Your main problem will be finding one with a sufficiently high VA rating (often not quoted!) to give you the 1.1 V rms or so that the emonTx analogue input needs. You may find it easier to find a 300:5 or 300:1 which will certainly need a higher power off-board burden resistor.

If you can only find one with a 0.333 V output, you could use an amplifier (external to the emonTx of course) with a gain of 3 to boost the signal, or you could try switching the analogue reference to use the internal 1.1 V reference, which would give you a better usable range (reading up to 330 A approx), hence better resolution. But that requires some fairly advanced programming. IIRC, calypso_rae has tried a Magnelab one like that, and was happy with it, but it was not the 300 A model.

tomtobback's picture

Re: 300 A current sensor CT

I'm using a 200A CT from the same manufacturer (YHDC Beijing, China) as the standard SCT-013


Main reason i got it is not high currents, but the standard SCT-013 did not fit around a wire i wanted to monitor, see http://lantaukwcounter.blogspot.hk/2013/04/calibrating-sct-019-000.html

A bit hard to open and close, but works fine after repairing sloppy soldering on the jack. I don't find its VA rating in the specs.

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