OT: Current Transformer - size matters?

5000 X 5 current transformer has an oval window about 9" X 5" (23cm x 13cm) but the water cooled buss bar passing through it is only about 1.5" (4cm) in diameter. We're having considerably difficulty calibrating the 5A x 10V signal conditoner to match a calibrated current sensor. While I suspect the problem is the signal conditoner I'm wondering if the size of the CT window can be a factor.

You did mean 5000:5 didn't you? From the dimensions you gave it sounds like a C or U split core, they are not as efficient as toroidal. I have not dealt with current that high but I have had to use or have some made to work with buss bars and the first thing they want to know is buss bar conductor sizing. I have never seen one be that much larger then the conductor.

Its an oval torroidal type CT, and yes, it is a five thousand by five CT. We have multiple 2KA, 5KA and 10KA power supplies (low voltage). I usually use water cooled buss bars. In this case the CT was designed for an air cooled buss bar but I installed a water cooled buss bar but did not replace the CT, and I'm wondering if that is the problem. Another possibility is that the CT burden is close to 30VA - though I'm pretty sure the CT is rated for it.

Try walking past one of these buss bars with a magnet in your pocket.

Please bear with an old tech

I know this is being picky but its 5000:5 as in a ratio; which is expressed 5000 TO 5, your using the terms 5000 by 5 or 5000 x 5 is very confusing to me.

I would suspect the size and design may have an effect on the CT, may want to talk with the manufacturer. I may not have dealt with those current ranges but have dealt with different ranges in numerous application, usually when donut hole was larger it designed for use of multi wire turns thru it.

First the C/T window shouldn't be a problem.

Second, you should be able to gt the max burden for the C/T from the manufacturer's data. Don't forget to include the wiring load if your leads are of any appreciable length. Usually, though, high ratio C/Ts have a pretty high allowable burden.

Finally, I have had problems with a amp transmitter being physically too close to the C/T. It seem that the magnetic field from all that iron throws off the transmitter. This was with a 4-20 mA output unit. If you are using a voltage output the impact is probably even greater. Make sure your output cable from the transmitter is well shielded.

I 2nd this

Finally, I have had problems with a amp transmitter being physically too close to the C/T. It seem that the magnetic field from all that iron throws off the transmitter. This was with a 4-20 mA output unit. If you are using a voltage output the impact is probably even greater. Make sure your output cable from the transmitter is well shielded.

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I have had this problem as well.