Current transformer Q

[ishiboo]

I purchased a 20kw PTO generator for my tractor, and I'm adding a digital frequency meter/voltage/current/etc. to it. The current portion uses a single current transformer.

If I put both hot legs through it, will I see the sum of the current, or the difference? I believe they cancel out, so if was 20A/20A flowing through I would see 0A since they are opposing phases, but I want to make sure.

Need to know if I'll need to have two (one per phase) or if one is sufficient.

 

[nehog]

Only one leg. Can't be neutral unless you want to measure the difference between the two legs. So you will need two meters (one for each leg...)

 

[Rookie2]

You will need two , you can use an toggle switch on-off-on to switch between them.

 

[rockwithjason]

If you run both legs thru the ct you will see the difference in the two. Be careful with the toggle switch as cts become step up voltage transformers when disconnected from the circuit. This can cause a flash over and destroy expensive things. Any ct on a live circuit must either be loaded or shorted, never open.

 

[ishiboo]

Sounds great all, thanks. I was pretty sure I was right but it helps to have confirmation.