trivector meters are used to measure kVAh and also kVA of
maximum demand.it has a kwh meter and reactive kvah meter in
a case with special summator mounted between them.
this is a instrument, which measures kvah and also kva of maximum demand. it consists of a kwh meter and a reactive kvah meter in the common case with a special summator mounted between them. the summator is driven by both the meters through a complicated gearing, which makes the summator to register kvah at all power factors.