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Problem
Nuisance or false close
Circuit breaker will not trip
Nuisance or false trip
Symptoms
Electrical problem
Mechanical problem
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. Nuisance or false closing signal to secondary
disconnect 13. Check protective relay logic. Correct as
required.
2. Closing coil (52SRC) terminal A2 is shorted-to-ground.
Check to determine if problems are in wiring or coil.
Correct as required.
1. Mechanical failure of operating mechanism. Check and
contact regional service centers, the factory or
telephone Siemens field service at +1 (800) 347-6659
or +1 (919) 365-2200 outside the U.S.
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 1.
Check for continuity and correct protective relay logic.
4. Secondary disconnect contacts 1 or 2 are not engaging.
Check and replace if required.
5. Failure of trip coil (52T). Check and replace if necessary.
6. Auxiliary switch 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 regional service centers, the factory or
telephone 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-
disconnect contact.
2. Check for improper protective relay logic.
1. Mechanical failure of operating mechanism. Check and
contact regional service centers, the factory or
telephone Siemens field service at +1 (800) 347-6659
or +1 (919) 365-2200 outside the U.S.
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