| Fault Phenomenon | Core Judgment Basis (What to Check First) | Possible Causes | Risk Level | Handling Reminder |
|---|---|---|---|---|
| Breaker body is already closed, but green lamp remains lit (signal inconsistent with actual position) | 1. Mechanical open/close indicator on breaker body 2. Observe breaker body status and confirm whether primary circuit is actually energized | Auxiliary contact stuck / eroded Secondary wiring short circuit Lamp holder damaged | High risk Easy to misjudge equipment as de-energized, causing electric shock | Never use the lamp as the basis for determining live/de-energized; check control circuit; de-energize before servicing auxiliary contacts. |
| Breaker body is already open, but red lamp remains lit (signal inconsistent with actual position) | 1. Mechanical open/close indicator on breaker body 2. Confirm primary side is de-energized | Auxiliary contact welded/stuck Secondary signal wire shorted to power supply Lamp holder insulation breakdown | High risk Mistakenly believe equipment is running; accidental touch during maintenance | Open secondary control MCB to assist judgment; de-energize and inspect auxiliary contacts and wiring. |
| Red and green lamps both lit | Mechanical position indicator on breaker body, regardless of lamp status | Auxiliary contact partially conducting/intermittent Loose connection or grounding in secondary circuit | High risk Position signal completely invalid | Prohibit open/close operations; troubleshoot secondary signal circuit. |
| Red and green lamps both off | 1. Whether manual open/close operation of breaker body is normal 2. Check secondary control power MCB and fuse | Control power lost Fuse blown Indicator lamp / lamp holder burned out | Medium risk Cannot observe position from panel | Check secondary control power first, then replace indicator lamp for troubleshooting. |
| Body already charged (energy stored), but yellow energy-storage lamp not lit | Mechanical energy-storage indicator plate on breaker body | Energy-storage limit switch fault Energy-storage power supply lost Energy-storage indicator lamp damaged | Medium risk Unable to determine energy-storage status; closing may fail | Verify mechanical energy-storage indication; check energy-storage circuit wiring and limit switch. |
| Body not charged (no energy stored), but yellow energy-storage lamp remains lit | Mechanical energy-storage indicator plate on breaker body | Energy-storage motor fault Limit switch misaligned Wiring error | Medium risk Switch cannot perform closing operation | Check energy-storage motor and limit switch; manually charge to test mechanism. |
| Energy stored in place, but switch cannot close | 1. Mechanical energy-storage indication on body 2. Truck position (service/test position) 3. Interlock contact status | Mechanism not charged Truck not in position Blocking interlock not released Closing coil damaged / circuit broken | Medium risk Equipment cannot be energized and put into operation | First confirm energy storage and truck in position; do not press the closing button repeatedly. |
| Pressing open button, switch cannot open | 1. Mechanical status of breaker body 2. Try manual mechanical emergency open button | Opening coil burned out Secondary circuit broken Mechanism mechanically jammed | Extremely high risk Cannot cut off power in fault state | Prioritize manual mechanical opening; prohibit repeated electrical operation; de-energize and service mechanism. |
| Truck position indicator lamps disordered, inconsistent with actual truck position | Mechanical latch and positioning of truck body; observe racking-in depth | Truck travel switch striker offset/shifted Travel switch damaged | High risk Misjudge truck service/test position; rack truck under load by mistake | Verify truck mechanical positioning; adjust or replace position travel switch. |
| No primary equipment fault, but fault alarm lamp remains lit | Protection device messages, event records, primary equipment status | Protection relay contact stuck/welded Fault signal not manually reset | Low risk False alarm, interferes with judgment | Perform signal reset on protection device; check alarm relay contacts. |
| Tripping has occurred, but fault alarm lamp does not light | Protection device trip event records, messages | Signal circuit broken Alarm lamp damaged Protection did not drive signal contact | Medium risk After trip, no fault indication on site | Check internal protection events; service alarm signal circuit. |
