Operation: CP1SD/T/L Version
90
CENTRON® Polyphase Meter Technical Reference Guide
where:
N = Coil factor (See Testing With the Infrared Test
LED)
SPTC=Single phase test constant (See the table in
Demand Test Method)
Calculation D: Actual kVA Demand
kVA = kVAh x 60/T
where:
T = Test Mode demand interval length in minutes
Field Testing
Field testing of the CENTRON Polyphase meter may be accomplished with conventional
methods using either the infrared test pulses or the load emulation annunciator.
Required Hardware
The typical field test setup consists of a phantom load, a portable standard, and an infrared
test pulse adapter with counter or snap switch assembly.
Test Method Using Infrared Pulse Adapter
The pulse adapter runs the test for a programmed number of pulses. The number of pulses is
set on the test pulse adapter by the use of counter switches. The adapter will automatically
start the test when the START COUNT button is pressed.
When the test begins, the test pulse adapter counts the pulses it receives from the meter until
the programmed number of pulses have been received.
When this occurs, the pulse adapter automatically shuts off the portable standard. The
standard then displays the number of equivalent disk revolutions which is then compared to
the number of pulses for the test.
Test Method Using a Snap Switch Assembly
This method is similar to the above except starting and stopping of the standard is
performed manually.
To conduct the test, the technician observes the position of the load emulation annunciator
and simultaneously starts the standard through the snap switch. After observing a
predetermined number of emulated disk rotations, the technician stops the standard with the
snap switch. A comparison is then made between the predetermined number of emulated
disk rotations and equivalent disk rotations indicated on the watthour standard.
