| Fault | Effect on System | Possible Consequence | Detection/Monitors | Response/Action Taken |
| Water leak inside magnet | Temperature rise in affected FEMs. Moisture collected inside the magnet. | Overheating of FEMs. Corrosion inside magnet. | Water detector at bottom of magnet interior. Water flow to input manifold monitored. Water temperatures monitored at input and output manifolds. Temperature sensors on all FEM cards. | Operator can identify the octant where the leak occurs and remotely turn power off to the octant. If the water leak is serious, then all power and water may need to be shut off for the whole set of octants. FEE cards have passive overcurrent protection. |
| Water leak outside magnet | Temperature rise in affected FEMs. Water possibly collected near power feeds. | Overheating of FEMs. Electrical hazard. | Water flow @ input to water supply manifold. FEM temperature sensors. | Operator can identify the octant where the leak occurs and remotely turn power off to the octant. If the water leak is serious, then all power and water may need to be shut off for the whole set of octants. FEE cards have passive overcurrent protection. |
| Water pump malfunction | Temperature rise in affected FEMs. | Overheating of FEMs. | Water flow @input to water supply manifold. FEM temperature sensors. | All octants serviced by the defective pump should be powered off remotely. FEE cards have passive overcurrent protection. |
| Dry gas leak outside magnet | Moisture may form inside FEMs. | Increased current draw or electrical breakdown in FEMs. | Dry gas flow monitored at input manifold. FEM current sensors and polyfuses. | Operator cannot identify where the leak occurs without an entry into the IR. No response for small leaks. For large leaks: An FEE power shutdown, a dry gas shutdown and an entry are required. FEM cards have passive overcurrent protection. |
| Over voltage at power supply output | Excess voltage or current at attached FEMs. | Failure of power regulation or voltage conversion in attached FEMs. Excess current draw in attached FEMs. | Voltage @ each LV power supply output. FEM voltage and current sensors and polyfuses. | Alarms will identify the affected octant; operator can remotely turn off power to the octant. FEM cards have passive overcurrent protection. |
| Low voltage at power supply output | Insufficient voltage or current at attached FEMs. | Failure of power regulation or voltage conversion in associated FEMs. Unstable operation of attached FEMs. Readout errors. | Voltage @ each LV power supply output. FEM voltage and current sensors. FEM output data stream and readout system status. | Alarms will identify the affected octant; operator can remotely turn off power to the octant. Operator will also monitor FEM data output and readout system status. |
| Over current at power supply output | Excess current at attached FEMs. | Failure of power regulation or voltage conversion in attached FEMs. Excess current draw in attached FEMs. | Current @ each LV power supply ouput. FEM current sensors and polyfuses. | Alarms will identify the affected octant; operator can remotely turn off power to the faulty LV power supply. FEM cards have passive overcurrent protection. |
| Over current on any FEM card | High current leads to temperature rise on circuit. PTC polyfuse opens on card. | Self-protecting shutdown of associated FEM card. Readout errors may ensue, depending on specific card missing. | PTC polyfuses. FEM current sensors. FEM output data stream and readout system status. | Alarms will help operator identify faulty FEM and even specific card if Slow Controls Interface or Power Card are not faulty; operator can remotely cycle power to attempt reset, or leave power off if failure cannot be obviated. |
| Low current at power supply output | Insufficient power to attached FEMs. | Failure of power regulation or voltage conversion in associated FEMs. Unstable operation of attached FEMs. Readout errors. | Current @ each LV power supply ouput. FEM current and voltage sensors. FEM output data stream and readout system status. | Alarms will help operator identify the affected octant; operator can remotely turn off power to the octant. Operator will also monitor FEM data output and readout system status. |
| Short circuit at power connector to chassis | LVDC power supply shuts down. All chassis connected to supply have no power. | Readout errors. | Remote on/off indicator on FEM power card. FEM output data stream and readout system status. | Alarms will help operator determine which LVDC PS has failed. Operator will also monitor FEM data output and readout system status. |
| Open circuit at power connector to chassis | LVDC power supply not affected. Only single chassis has no power. | Readout errors. | Remote on/off indicator on FEM power card. FEM output data stream and readout system status. | Alarms will help operator identify faulty chassis; operator can remotely shut off power to associated FEM(s). Operator will also monitor FEM data output and readout system status. |
| Voltage regulator on power card fails. No output from FEM power card | All FEM cards have no power. | Readout errors. | FEM output data stream and readout system status. | Operator can determine which FEM has failed from lack of FEM data output and via readout system status. |
| Voltage regulator on other FEE card fails. | Non-power FEE card goes unstable or catatonic. | Readout errors. | FEM output data stream and readout system status. FEE card current and voltage sensors. | Operator can determine which FEM has failed from data output and readout system status. If Slow Controls Interface and Power Card are okay specific FEE card can be identified from FEE card current and voltage sensors. |