Advertisement
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 multi-pin plug contact. 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 the factory or 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 multi-pin plug contact C2.
Check for continuity and correct protective relay
logic.
4. Secondary multi-pin plug contacts C2 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.
43
Advertisement
