Iskra MC320 - Voltage; Current; Active, Reactive and Apparent Power; Power Factor and Power Angle

MEASUREMENTS

Measuringcentres–M
C
320,MC330,MC350&MC350H ‐ User’sManual 43

Voltage  
Instrumentmeasuresrealeffective(rms)valueofallphasevoltages(U
1
,U
2
,U
3
)connectedtothemeter.Phase‐
to‐phase voltages (U
12
, U
23
, U
31
), average phase voltage (U
f
) and average phase‐to‐phase voltage (U
a
) are
calculatedfrommeasuredphasevoltages(U
1
,U
2
,U
3
).
N
u
=
U
2
n
N
1=n
f



N
2
ynxn
N
1=n
xy
uu
=
U



Allvoltagemeasurementsareavailableviacommunication,serialandcustomizeddisplaysonLCD.
MainmenuMeasurementsPresentvaluesVoltageOK
Current  
Thedevicemeasuresrealeffective(rms)valueofphasecurrents,connectedtocurrentinputs.Neutralcurrent
(I
n
),averagecurrent(I
a
)andasumofallphasecurrents(I
t
)arecalculatedfromphasecurrents.
N
i
=
2
n
I
N
1=n
RMS


Allcurrentmeasurementsareavailableviacommunication,serial(exceptI
t
)andcustomizeddisplaysonLCD.
MainmenuMeasurementsPresentvaluesCurrentOK
Active,reactiveandapparentpower  
Active power is calculated from instantaneous phase voltages and currents. All measurements are seen via
communicationoraredisplayedonLCD.FormoredetailedinformationaboutcalculationseechapterEquations
onpage72.
MainmenuMeasurementsPresentvaluesPowerOK
Powerfactorandpowerangle  
Powerangleiscalculatedasquotientofactiveandapparentpowerforeachphaseseparately(cos
1
,cos
2
,
cos
3
)andtotalpowerangle(cos
t
).Asymbolforacoilrepresentsinductiveloadandasymbolforacapacitor
represents capacitive load. For correct display of PF via analogue output and application of the alarm, ePF
(extendedpowerfactor)isapplied.Itillustratespowerfactorwithonevalueasdescribedinthetablebelow.For
adisplayonLCDbothofthemhaveequaldisplayfunction:between‐1and‐1withtheiconforinductiveor
capacitiveload.

Load C
 
L
Angle[°] ‐180 ‐90 0 +90 +180(179.99)
PF ‐1 0 1 0 ‐1
ePF ‐1 0 1 2 3

MainmenuMeasurementsPresentvaluesPF&PowerangleOK
ExampleofanalogueoutputforPFandePF(MC350andMC350Honly):

