Operation: CP1SD/T/L Version
CENTRON® Polyphase Meter Technical Reference Guide
89
Meter Single Phase Test Constants (SPTC)
Form
Series
A Phase
Only
B Phase
Only
C Phase
Only
9 or 16
3Ø, 3W,
0.911
.866
.0866
1
9, 16, or 14
3Ø, 4W, wye
1
1
1
1
This test method is valid for kWh, kVAh, kvarh, kW, kVA, and kvar at any load or
power factor.
Demand Calculations
With solid-state metering, conducting energy and demand tests may be considered
redundant since they are both results of the same measurement.
Calculation A: Actual Active Energy (kWh)
Actual active energy is calculated using the following formula:
kWh = P
T
x Kh x N/1000
where:
Kh = watt-hours per pulse output value from the reference
standard. (A watt and/or a VA standard must be used.)
P
T
= Total pulses accumulated from the reference standard
N = Coil factor (See Testing With the infrared Test LED)
Pre-calculate the total pulses expected with the following formula to ensure that the pulse
counter display does not overflow:
P
T
x Kh = V x I x T/(Kh x 60)
where:
V = Voltage applied to standard
I = Current applied to standard
T = Test Mode demand interval length in minutes
If Test Mode display is in watt-hours (Wh), divide by 1000 to get kWh.
Calculation B: Actual Active Demand (kW)
Actual active demand is calculated using the following formula:
kW = kWh x 60/T
where:
T = Test Mode demand interval length in minutes
Calculation C: Actual KVA Hours
kVAh = P
T
x Kh x N/ (1000*SPTC)
