Siemens 3AH3 Instruction Manual page 49

Problem
Circuit breaker will not trip.
Nuisance or false trip
Symptoms
Tripping coil or solenoid (52T) does not
energize. There is no tripping sound.
Tripping coil (52T) energizes. No tripping
sound is heard, and circuit breaker contacts do
not open. In other words, they remain closed.
Tripping coil (52T) energizes. Tripping sound is
heard, but circuit breaker contacts do not
open.
Electrical problem
Mechanical problem
Table 8: Troubleshooting (continued)
Possible causes and remedies
1. Secondary control power is de-energized or
control power fuses are blown. Correct as
indicated.
2. Damage to wiring, terminals or connectors.
Check and repair as necessary.
3. No tripping signal to secondary disconnect
contact C2. Check for continuity and correct
protective relay logic.
4. Secondary multi-pin plug contacts C1 or D2
are not engaging. Check and replace if
required.
5. Failure of trip coil (52T). Check and replace
if necessary.
6. Auxiliary switch 52a NO contacts 23 to 24
or 33 to 34 are open when circuit breaker is
closed. Check linkage and switch. Replace
or adjust as necessary.
1. Failure of tripping spring or its mechanical
linkage. Check and replace if required.
1. Mechanical failure of operating mechanism.
Check and contact the factory or Siemens
field service at 1-800-347-6659 or 1-919-
365-2200 outside the U.S.
2. One or more of the vacuum interrupters are
held closed. Check and replace as necessary.
1. Tripping signal remains energized on
secondary multi-pin plug contact C2.
2. Check for improper protective relay logic.
1. Mechanical failure of operating mechanism.
Check and contact the factory or Siemens
field service at 1-800-347-6659 or 1-919-
365-2200 outside the U.S.
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