How to test a CT Sensor (Alternating Current Clamp)?

Question

I recently purchased a CT clamp. I am left wondering what the best way is to test this in a laboratory environment, specifically with an AC current generator. I just want to know whether the device works properly.

Could I just generate a fixed amount of AC current from the generator and short my negative and positive wires to create a current loop? From this, could I then just clamp my CT sensor around this loop?

If not, I am open to more suggestions! Any help is greatly appreciated!

Kind regards,

Hashim Shamsi

Answer 1

If you have an accurate AC ammeter you can find a reasonably steady, reasonable resistive load (perhaps a heat lamp, for example) that is somewhere between half and full scale of the probe, run one of the AC wires through the probe, through the ammeter, and compare the probe output to the AC ammeter.

If you can only find a load that is (say) between 1/4 and 1/2 or between 1/6 and 1/3 etc. you can thread multiple turns through the clamp-on probe to multiply the effective current.

It is essential that the turns are from one side of the AC and are only threaded through in one direction, otherwise they will cancel.

Answer 2

Take a resistive load of known value (say, a small space heater that lacks a fan), and use the CT on the hot wire going to it, hooked up to a meter. You should be able to get clamp adapters that plug into an outlet and break hot and neutral out to the two "arms" before coming back together into a socket, as depicted below in a representative North American version, at an electrical supply house or even a home-improvement/hardware store.

Once you have everything set up, you should be able to use the docs for your CT to convert your meter reading to a current reading, then match that up with the nameplate wattage on your load. (space heater, electric griddle, what have you)

Answer 3

I suggest you have read the manual yet or even the wiki notes. https://en.wikipedia.org/wiki/Current_clamp#Clamp_meter

Calibration requires standards. If your range is variable then try all known current sources you have ( such as your 50 Ohm generator into a 50 Ohm load) then sweep and see what errors are found. Be aware of DC and degaussing.