Rockwell Automation 1902 Syncpro II - Manual (Page 51)

Rockwell Automation Publication 1902-IN001B-EN-E - April 2013 53
Chapter
6
Monitoring
Phase Angle/Power Factor A key protection component of the SyncPro II is to monitor Power Factor.
Monitoring Power Factor is one of the most reliable methods to determine if a
motor is running properly. The SyncPro II system utilizes a Phase Angle
Transducer which provided a proportional signal to the measured phase angle
(angle difference between motor voltage and current).
The phase angle transducer board provides a 4...20mA output proportional to
-90...90º. The SyncPro II utilizes this input to calculated Power Factor.
To provide an accurate measurement the voltage and current inputs must be in
the proper relationship, V
ab
and I
c
.
Figure 30 - Voltage and Current Inputs Relationship
) (θ Cos PF =
Va
Vb
Ic
Vab