XT2640 Operating Manual
13 July 2016
Page 30 of 187
11.5
INDIVIDUAL
VPA
TOTAL
RESULTS
11.5.1
VOLTAGE
RESULTS
VPA total measurement results given for voltage is the average phase voltage for the VPA depending on the WIRING setting for the
VPA‐
3ø3w(2ch) or 3ø3w(3ch) The mean of the øAC, øBC and øAB voltages.
Otherwise
The mean of all channel voltages in the VPA
11.5.2
WYE
VOLTAGE
RESULT
This is only available for a VPA configured as 3ø3w(2ch) or 3ø3w(3ch) and is (mean of the øAC, øBC and øAB voltages)/√3.
11.5.3
DELTA
VOLTAGE
RESULT
This is only available for a VPA configured as 3ø4w and is the mean of the measured øAC, øBC and øAB voltages.
11.5.4
CURRENT
RESULTS
VPA total measurement results given for current is the average phase current for the VPA depending on the WIRING setting for the
VPA‐
3ø3w(2ch)
The mean of the øA, øB and øC currents.
Otherwise
The mean of all channel currents in the VPA
11.5.5
WATTS
RESULTS
VPA total measurement results given for Watts are the total power computed for the entire VPA. This is always the sum of the Watts
for each channel in the VPA.
11.5.6
VAR
AND
VA
RESULTS
VPA total measurement results given for VAR and VA are the total power computed for the entire VPA. Depending on the VA/VAR
preference configuration setting for the VPA this is one of the following‐
Σ(VAR) setting
VAR is the sum of the VAR for the channels in the VPA
VA is computed directly from the W and VAR using (total VA)
2
= (Σ(W))
2
+ (Σ(VAR))
2
Σ(VA) setting
VA is dependent on the WIRING setting–
3ø3w(2ch) setting: total VA = (Σ(VA)) * (√3) / 2 or for other settings: total VA = Σ(VA)
VAR is computed directly from the W and VA using (total VAR)
2
= (Σ(VA))
2
‐ (Σ(W))
2
with polarity taken
from the sum of the VAR for the channels in the VPA
11.5.7
POWER
FACTOR
RESULTS
VPA total measurement results given for PF are always computed from the total Watts and VA for the VPA.
11.6
INRUSH
RESULTS
In most cases measurement results denoted as Inrush in the XT2640 are the highest recorded respective measurement result since
inrush measurement collection was last reset. The exceptions to this are –
Valley Inrush
The lowest recorded valley measurement result.
VPA Voltage Inrush
The highest recorded voltage of any phase in the VPA depending on the WIRING setting for the VPA
3ø3w(2ch) or 3ø3w(3ch)
øAC, øBC and øAB voltages
Otherwise
Each phase voltage
VPA Current Inrush
The highest recorded current of any phase in the VPA depending on the WIRING setting for the VPA
3ø3w(2ch)
øA, øB and øC currents
Otherwise
Each phase current
11.7
PHASE
RESULTS
All phase measurement results are given in degrees using either a ‐180° to +180° or a 0° to 360° range as defined by the preferences
menu setting (see 12.3.1.6).
In many situations the mathematical definition of phase is used, i.e. if a phase ø
21
is returned for signal S
2
with respect to signal S
1
,
then signal S
2
is mathematically S
2
.sin(ωt + ø
21
) and S
1
is S
1
.sin(ωt). However it is not uncommon in some industry segments to use a
“delay” based definition of phase as illustrated by the drawing shown below‐
