Iskra MT440 - Equations

AppendixB:Calculations&equations
User’sManual 53
8.2 Equations
Voltage
N
u
=
U
2
n
N
1=n
f
∑
Phase voltage
N − 128 samples in one period (up to 65 Hz)
N − 128 samples in M
v
periods (above 65 Hz)
Example: 400 Hz → N = 7
()
N
2
ynxn
N
1=n
xy
uu
=
U
−
∑
Phase-to-phase voltage
u
x
, u
y
− phase voltages (U
f
)
N − a number of samples in a period
Current
N
=
i
I
2
n
N
1=n
RMS
∑
Phase current
N − 128 samples in a period (up to 65 Hz)
N − 128 samples in more periods (above 65 Hz)
()
N
iii
=
2
n3n2n1
N
1=n
n
I
++
∑
Neutral current
i − n sample of phase current (1, 2 or 3)
N = 128 samples in a period (up to 65 Hz)