How to measure the KW of a Generator

I have a question just for my own understanding. I have a generator with has L1, L2 and N

To measure the total KW output, do I measure the amps on L1 and L2, add them together and x 120?

so 10a on L1 and 5a on L2 would be 15a total, and x120 would be 1800w

Would I need a CT on the neutral?

What you are describing is VA not Watts. IoTaWatt will give you VA for each of L1 and L2 and you can add them together.

Watts is something else and is always <= VA.

To monitor generator output, VA may be a better choice as it must produce the reactive power as well.

Thanks, thanks good information

I’m correct that I would calculate it by x120? I’m actually comparing the Genmon output which appears to be incorrect as its seems to be x240 which ends up doubling the output

Not sure what you are trying to do. Are you trying to get this with Graph+, query or something else?

In general, a script that adds together L1 and L2 with units = Watts will give you the total generator output. (You don’t need to measure the N). At issue is whether your VT is connected to the generator output so that you get a voltage reference. If your VT is on a circuit not fed by the generator, you cannot measure anything from the generator accurately unless you:

  1. Add the VT circuit to the generator output.
  2. Move the VT to a circuit on the generator output.
  3. Add a second VT on the generator output (input 13 or 14) and specify that as the reference for the generator L1 and L2 CTs.

If you have a situation where some of the house is on the grid and some is on the generator, then option 3 is your only choice.