Table 7-1 Measuring Instruments
Item
Instruments
Type of Instrument
Remarks
Supply voltage
E1
E
L1-L2
, E
L2-L3
and E
L3-L1
Moving iron type voltmeter or
Rectifier type voltmeter
Fundamental wave
effective value
Supply current
I1
I
L1
, I
L2
and I
L3
Moving iron type ammeter
Total effective value
Supply power
W1
W
11
and W
12
Electrodynamics wattmeter
Total effective value
Supply power
Factor Pf1
Calculate from above measured values E1, I1 and W1
Pf
W
E I
1
3
100
1
1
1
=
⋅ ⋅
×
(%)
Output voltage
Eo
E
U-V
, E
V-W
and E
W-U
According to Fig.7-1 and Fig.7-2
Total effective value
Output current
Io
I
U
, I
V
and I
W
Moving iron type ammeter
Total effective value
Output power
Wo
W
O1
and W
O2
Electrodynamics wattmeter
Total effective value
Output power
factor Pf2
Calculate from above measured values Eo, Io and Wo
Pf
W
E
I
O
O
O
1
3
100
=
⋅
⋅
×
(%)
NOTE :
Use a meter indicating a fundamental wave effective value for voltage, and meters indicating
total effective values for current and power.
7-3
