Hioki 3197, Instruction Manual

Page: 164 / 200

8.5 Calculation Formulas
156
Basic Calculation Formulas
8.5 Calculation Formulas
Wiring
Configuration
Parameter
Single-
Phase
2-Wire *1
Single-Phase
3-Wire
Three-phase, 3-wire Three-Phase 4-Wire
1P2W 1P3W 3P3W2M 3P3W3M 3P4W 3P4W2.5E
Voltage (1/2)
U(1/2) [Vrms]
U
1
U
1
U
2
Inter-line voltage
U
1
U
2
U
3
(U
3s
=-U
1s
+U
2s
)
( U
1s
+(-U
2s
)+U
3s
= 0
are assumed)
Inter-line voltage
U
1
(U
1s
=u
1s
-u
2s
)
U
2
(U
2s
=u
2s
-u
3s
)
U
3
(U
3s
=u
3s
-u
1s
)
Phase voltage
U
1
U
2
U
3
Voltage
U [Vrms]
U
1
U
1
U
2
Inter-line voltage
U
1
U
2
U
3(U
3s
=-U
1s
+U
2s
)
(
U
1s
+(-U
2s
)+U
3s
= 0
are assumed)
Inter-line voltage
U
1
(U
1s
=u
1s
-u
2s
)
U
2
(U
2s
=u
2s
-u
3s
)
U
3
(U
3s
=u
3s
-u
1s
)
Phase voltage
U
1
U
2
U
2
(U
2s
=-U
1s
-
U
3s
)
(
U
1s
+U
2s
+U
3s
=
0
are
assumed)
U
3
•
Subscript definitions
c: Measurement channel (1 to 3); 1, 2, 3: Measurement channel; M: Sample count; s: Sample point
number;
ave
: average of multiple channels; sum: sum of multiple channels
• Variable definitions
U: Inter-line voltage (three-phase 4-wire phase voltage), u: phase voltage from virtual neutral
*1. Formulas that apply to inputs 1 to 3 for single-phase wiring also apply to c in other wiring configurations.
Uc
1
M
----- Ucs
( )
2
S 0 =
M 1 –

=
Uave
U
1
U
2
+
2
------------------
=
Uave
U
1
U
2
U
3
+ +
3
------------------------------- =
Uc
1
M
----- Ucs
( )
2
S 0 =
M 1 –

=