Why can you not install the Enercept Meter on the line or load side of a Variable Frequency Drive (VFD) unit?

Issue:
A user wants to use an Enercept meter to monitor a Variable Frequency/speed Drive (VFD), and perhaps on the line side.

Product Line:
Enercept Meter

Environment:
Enercept Meter and VFDs

Cause:
The Enercept meter cannot be used to monitor a Variable Frequency/Speed Drive on the line or load side.

The reason is that, by design, the processor and electrical components are mounted on the current transformer (CT). Any frequency other than 60 Hz, such as harmonics from a VFD, will degrade the electrical components on the CTs.

This has been verified by Veris.

Resolution:
Installation manuals prior to Z205397-0C indicate that it is OK to install the meter on the line side of a VFD. As of January 2011, this is no longer supported for any Enercept Meters regardless of their Date of Manufacture.