Eaton Power Xpert PXM 4000, User And Installation Manual

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7 Functions on the Graphical Display
7.3. Energy
The Power Xpert Meter measures and accumulates Real Power (Watts), Reactive Power (Vars)
and Apparent Power (VA) every 200 milliseconds. The means of accumulated four different kinds of
accumulation; forward, reverse, net and sum for Real Power and Reactive Power. These measure-
ments are configured to calculate the kWh Forward, kWh Reverse, kWh Net, kWh Sum, kvarh Lag,
kvarh Lead, kvarh Net, kvarh Sum and kVAh.
Real Power (Watts) is the square root of the sum of the instantaneous voltage mutliplied by current.
•
Reactive Power (kvar) is the product of the voltage, the current and the sine of the
phase angle between them.
•
Apparent Power (kVA) is the square root of the sum of the squares of the active and
reactive powers.
Separate energy registers accumulate energy values over a period of one calendar month. At the
end of every month, energy and peak demand values with date and time stamps are saved as last
months values. The energy accumulators then reset and begin accumulating values for next month.
Real-time Pricing
In addition to the above, Power Xpert Meter also computes separate energy values for Real-Time
Pricing (RTP). RTP can be activated by any the discrete inputs to the meter when configured. The
meter determines the energy consumed for individual rate periods and saves the information with
the date and time of the occurrence. Present energy and previous energy values are made avail-
able along with energy consumed data, over any available communication port and display.