Different kw readings

[Estiban]

Hello,

I’m testing some electric meters.
As the circuits have no load on them to prove each ct I’ve plugged a hair dryer to simulate a load and put the ct around the line of the hair dryer to check measurements are the same as a calibrated meter.
The Ct’s from each phase read the same Amps however the kw reading is twice as high for the L2 Ct which is the circuit the socket is plugged into.
This also occurred when the sockets where L3 circuits in a different location then the L3 ct had twice the kw but the same amps as the other phases.
This was the same every time.

Would anyone know why this occurs ?
Many thanks

 

[plugsandsparks]

I think a diagram could help, also i assume your KW readings are from the meter you are testing. Again assume your hairdryer is single phase and the meters are three phase. How the meters are connected ? Type of meter?
End of the day to get accurate KW you need an accurate current and an accurate voltage.

 

[Estiban]

I think a diagram could help, also i assume your KW readings are from the meter you are testing. Again assume your hairdryer is single phase and the meters are three phase. How the meters are connected ? Type of meter?
End of the day to get accurate KW you need an accurate current and an accurate voltage.

hi,
Yes your right single phase dryer, Carlo gavazzi 271 meters and yes the reading is from the meter.

 

[plugsandsparks]

Have fitted those before. Not wanting to state the obvious but it is vital that the voltage inputs to the meter, L1, L2, L3 match exactly with the L1, 2, 3 current transformers. i.e. the line that you designate as L1 for voltage has to be the same line you designate for L1 for the CT
Please see connection diagrams in https://www.gavazzi.no/wp-content/uploads/EM271DS.pdf
Dont forget the neutral connection to the meter , also