Operation: CP1SD/T/L Version
CENTRON® Polyphase Meter Technical Reference Guide
77
Refer to the PC-PRO+ Advanced documentation for instructions on how to program this
value into the CENTRON Polyphase meter.
Diagnostic #3 Error Example
This example is for a Form 9S meter wired for a 277 volt, 4-Wire Wye system, but the site
has a shorted current transformer. The “low current value” is set at 25 mA.
The following is the information from the SiteScan snapshot when the Diagnostic #3 error is
triggered.
Phase A Display
(Left Element)
Phase B Display
(Center Element)
Phase C Display
(Right Element)
Voltage Phase
Angles
PhA 0.0° V
PhB 119.4° V
PhC 240.9° V
Phase Voltage
PhA 276.2 V
PhB 277.7 V
PhC 277.0 V
Current Phase
Angles
PhA 9.0° A
PhB ---------
PhC 246.0° A
Phase Current
PhA 11.8 A
PhB ---------
PhC 5.2 A
Diagnostic Counters
d1 000 d2 000
d3 001
d4 000 d5A 000 d5B 000
d5C
000 d5T 000 d6 000
The second step to diagnose a Diagnostic #3 error is to compare the different phase current
readings. In this case A and C phases both have current passing through the elements while
B phase (center element) has no current. The dashes indicate that current is zero or too low
to measure accurately. Accurate measurement is considered to be 0.5% of class rating for
the current:
CL 20 = 10 mA
CL 200 = 1 Amp
CL 320 = 1.6 Amps
This could indicate an open or shorted current transformer or current diversion. Also note
that diagnostic counter d3 has incremented to “001”.
It is possible to see dashes where the current information should be, but have no
Diagnostic #3 error present. See the SiteScan Toolbox Mode for more information.
