High Voltage Metering - E-Mon Class 3200 Installation Instructions Manual

11.0 HIGH VOLTAGE METERING

kWh Meter Installation Instructions for Use with E-MON
Meters in High Voltage Applications
The E-MON model # E34-12025HV kWh meter is designed to be used for monitoring
high voltage (2400, 4160, 13200, etc) circuits, either "stand alone" or in an AMR
application.
This meter is intended to be used with the appropriate high voltage Potential
Transformers (PTs) and Current Transformers CTs) supplied by others. The meter
application is centered around a 120 VAC secondary output from the high voltage PTs
and a 5 amp secondary output from the high voltage CTs.
Items addressed by this document include the installation of the E34-12025HV kWh
meter on high voltage circuits as well as the calculations to provide the correct meter
multiplier based on the PT and CT sizes used on the high voltage conductors.
Installation should be performed by qualified personnel and only according to all
applicable electrical codes.
High Voltage CTs (supplied by others) reduce the primary current (amps) to a directly
proportional 0~5 amp secondary output. As an example, a 0~400 amp primary
becomes a 0~5 amp proportional signal from the secondary output. In our application,
the high voltage CT secondary is installed as a continuous "loop", with a single
conductor connected to both secondary terminals.
To convert the 0~5 amp signal to a 0~ 2 volt signal, E-MON's Current Sensors are
installed on the CT secondary conductor. A set of 25 amp sensors is used in this
application. These sensors have the high voltage CT secondary conductor passed
through them five (5) times (see below) by looping the secondary conductor as shown
in the drawing. The reason for this is so that the 5 amp secondary now appears to the
current sensor as a 0~25 amp signal. This creates a conversion of the CT's primary
current to a directly proportional 0~ 2 volt signal which is utilized by the E-MON meter.
The example from the first paragraph has now become a 400 amp to 2 volt device, by
this technique.
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