DT3000
Instruction Leaflet
I.B. 17555D
Effective: Date 07/02
Page 37
For more information visit:
www.cutler-hammer.eaton.com
Supersedes I.B. 17555C dated November 1999
Circuit Breaker Trips
Much Faster than
Expected on Inverse
Time Overcurrent
(continued)
•
Zone Interlocking Used
•
Check for Absence of Blocking Signal from
“Down-Stream” Breaker
NOTE
:
During an Internal Test, there is No
Blocking Signal from a “DownStream” Breaker,
therefore, add jumper for test.
•
Paragraph
4-
2
Circuit Breaker Trips
Much Slower than
Expected on Inverse
Time Overcurrent
•
The Short Delay Time
Setting Determines the
Minimum Inverse Time
Overcurrent
•
Check Coordination Curves for Short Delay
and Inverse Time Overcurrent Settings
•
Section
7,
Paragraph 3-
3.1
•
Improper Wiring from
Protective Relay
•
Check Trip Relay Wiring
NOTE
:
Instantaneous and Override Trip
Functions Close the 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
Relay makes
•
Figure
3-1
•
Figure
3-1
Protective Relay
Indicates a Trip, but
Circuit Breaker
Doesn’t Open
•
Unit in Test Mode with “No
Trip Test Selected”
•
Select Trip Test while in the Test Mode
•
Check Wiring from Protective Relay to
Circuit Breaker Trip Coil
•
Check that Circuit Breaker has Source of
Tripping Power
•
Paragraph
3-
3.3
•
Wiring
Plan
Drawing
•
Wiring
Plan
Drawing
•
Breaker Contact to
Protective Relay not
Functioning
•
Check wiring from Breaker Dry Contact to
TB1-9 and TB1 -10 of Protective Relay
Terminal Block
•
Figure
3-1
and 5-3
Auto-Reset Function
not Operational
•
DIP switch S9 not set
correctly
•
Check DIP Switch S9 Setting
•
Check that Contact is Operational
•
Table
5.1
•
Figure
5-3
•
Dip Switch S9 not set
correctly
•
Check DIP Switch Setting
•
Table
5.1
Manual Reset
Function 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
SECTION 7: TIME-CURRENT CURVES
7-1 DIGITRIP 3000 INVERSE TIME OVERCURRENT
CURVES
The following pages contain the specific time-current
curves applicable to the Digitrip 3000 Protective Relay.
