Phase Measurement Tips
PhaseTrakker
AP30
32
Single-Phase Transformers
Single-phase transformers normally have one primary connection to supply volt-
age and one primary connection to ground. In this situation, one secondary con-
nection will be in phase with the primary, while the other will be 180
°
out of
phase. The transformer polarity determines which of the secondary connections
will be in-phase. The Field Unit can be set to compensate for this phase shift
(refer to the section Adjusting for Phase Shift)
Note: The table below assumes that all measurements (primary and
secondary) were taken with the same Field Unit Phase Shift setting.
Single-Phase Transformer Phase Readings
Primary
Secondary
In Phase
Secondary
Out of Phase
A
0°
A
0°
“No Match”
180°
B
-120° (240°)
B
-120° (240°)
“No Match”
60°
C
120°
C
120°
“No Match”
-60° (300°)
Phase angle readings will typically vary within 20° of values shown.
Phase angles and labels shown are the AP30 default values.
