The Current Transformers (CTs) of TeSys T are deigned to work under the frequency range between 47 to 63 Hz only.
However, the output frequency range of Altivar Variable Speed Drive varies from 0 Hz to 400 Hz. So when the TeSys T is placed in the downstream of the Variable Speed Drive, the CTs of TeSys T will not be able to sense the current values correctly, as the frequency of the current is not as per design specifications.
This will affect the TeSys T working and the outcome will not be the actual. So, it is not recommended to use the TeSys T in downstream of the Altivar Range Variable Speed Drives.