I.B. 17555
Page 39
Effective 03/97
Symptom
Probable Cause
Possible Solution(s)
Reference
Table 6.1 Troubleshooting Guide
Circuit Breaker Trips
Incorrect Settings
Check Settings
Paragraph 3-3.2 and
Much Faster than
Table 5.1
Expected on Inverse
Time Overcurrent
Phase Zone Interlocking not
Check for Phase Zone Interlocking
Figure 3-1
used and Jumper Missing
Jumper Between TB1-13 and TB1-14
Ground Zone Interlocking not
Check for Ground Zone Interlocking
Figure 3-1
Used and Jumper Missing
Jumper Between TB1-11 and TB1-12
Zone Interlocking Used
Check for Absence of Blocking
Paragraph 4-2
Signal from “Down-Stream” Breaker
NOTE: During an Internal Test, there
is No Blocking Signal from a
“Down-Stream” Breaker, there-
fore, add jumper for test.
Circuit Breaker Trips
The Short Delay Time
Check Coordination Curves for Short
Section 7,
Much Slower than
Setting Determines the
Delay and Inverse Time Overcurrent
Paragraph 3-3.1
Expected on Inverse
Minimum Inverse Time
Settings
Time Overcurrent
Overcurrent
Protective Relay
Improper Wiring from
Check Trip Relay Wiring
Figure 3-1
Indicates a Trip, but
Protective Relay
NOTE: Instantaneous and Override
Circuit Breaker Doesn't
Trip Functions Close the
Open
Contact Between TB2-12 and
TB2-13, while Inverse Time
Overcurrent and External Trip
Functions Close the Contact
Between TB2-14 and TB2-15
Check that Trip Contact on Protective
Figure 3-1
Relay makes
Unit in Test Mode with “No
Select Trip Test while in the Test Mode
Paragraph 3-3.3
Trip Test Selected”
Check Wiring from Protective Relay to
Wiring Plan Drawing
Circuit Breaker Trip Coil
Check that Circuit Breaker has Source
Wiring Plan Drawing
of Tripping Power
Auto-Reset Function not
Breaker “b” Contact to
Check wiring from Breaker “b” Dry
Figure 3-1 and 5-3
Operational
Protective Relay not
Contact to TB1-9 and TB1-10 of
Functioning
Protective Relay Terminal Block
DIP Switch S9 not set correctly
Check DIP Switch S9 Setting
Table 5.1
Check that “b” Contact is Operational
Figure 5-3
Manual Reset Function
Dip Switch S9 not set correctly
Check DIP Switch Setting
Table 5.1
not Operational
Damaged Reset Pushbutton
Replace Protective Relay
Paragraph 6-3
Caution: When the Digitrip 3000 Protective Relay is Powered, it Supplies Voltage to the “b” Contacts