A9MEM3255 energy meters connected in series

[Itch]

I have 2 x A9MEM3255 energy meters connected in series with one CT per phase on a switch board. The problem I am experiencing is the current reading on the display of the meters are not the same value. Can someone explain to me why this may be occurring. One party monitors one meter and another party monitors the other on the RS485 ports. They need to record the same value from each meter. The values are way out with each other.

[Mehran_Mehrnia]

Hi @Itch 

Please make sure CT ratios, and other config settings as well as wiring and installation are the same on both A9MEM3255 meters.

Thank you.

Best Regards,

-Mehran
L3 Expert Tech Support Specialist

[Itch · Accepted solution]

Hi Mehran,

I had the electricians check again and they had wired the meters in parallel with the CT's instead of putting the CT's in series with the 2 meters. They made the changes and now both meters are reading the correct values. 

They also earthed the S2 connection as the wiring diagram of the meters.

Cheers.

Cheers.

[Mehran_Mehrnia]

Hi @Itch 

Thank you for the update and now it makes sense.
Yes, CT's and PT's secondary grounding ensures safety of personnel and equipment and enhances the reliability of the power system and measuring devices.

Best Regards,

-Mehran

L3 Tech Support Specialist