IB 6.1.12.1-1B
3
2
ABB
Appendix B
Overcurrent Trip Devices
Table B1 - Standard Electro-Mechanical Overcurrent Trip Devices
Reference IB 8203 for OD Operating Instructions and Testing Procedure
Device Elements
Range of Pickup as a Percentage of
Device’s Coil Rating
Time-Current Curve
Overcurrent
Device
Type
Designation
LT ST INST AC DC
a
OD-3
General Purpose
b
50-125 500-1500 TD-6693 TD-9403
OD-4 Dual Selective 80-160 400-1000 TD-6694 TD-9034
OD-5 Triple Selective 80-160 400-1000 500-1500 TD-6695 TD-9402
OD-6 Dual selective 80-160 500-1500 TD-6695 TD-6695
OD-7 High INST 500-1500 TD-6695 TD-6695
OD-8 Special Low INST 80-250 TD-6695 TD-6695
a
DC devices may be tested with AC current when using a DC equivalent of 0.95AC
RMS
. If measuring device reads
AC
peak
, then obtain an AC
RMS
reading by dividing AC
peak
by √2.
b
The OD-3 long-time delay element has one wide range time delay band. All other OD devices with LT delay have three
time-delay bands.
Table B2 - Standard Solid-state Trip Devices
Reference IB 6.1.2.7-4 for Power Shield Operating Instructions and Testing Procedure
Device Elements Time-Current Curve
Device
Type
LT ST INST GND
Device in Red
a
Case
Device in Gray
Case
SS-3
✓
✓
TD-6966 TD-9001
SS-4
✓
✓
TD-6967 TD-9002
SS-5
✓
✓
✓
TD-6967 TD-9002
SS-13
✓
✓
N/A TD-9003
SS-14
✓
✓
N/A TD-9004
SS-15
✓
✓
✓
N/A TD-9004
SS-nG
b
✓
TD-6968 TD-9005
a
Device in red case was a previous manufacture (Prior 1974)
b
Ground type devices add a ground trip element to the “n” type functions.
SS-13, SS-14, & SS-15 have longer LT delays for special coordination applications.
Courtesy of NationalSwitchgear.com
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