06/25/19
Message Overview:
Fault Message:
GEN1 [PHASE NEUTRAL CROSSED]
Fault Code:
2421109LPS
Associated CAS:
| Reporting LRU: | Variable Frequency Generator (VFG) 1 |
| System Description: | 21-21-00 |
| Schematic Diagram: | 24-21-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 24-21-01 [ Global Express ] [ G5000 ] [ Global XRS ] |
Fault Description:
Variable Frequency Generator (VFG) 1 has tripped off-line or will not come on-line.
Possible Causes:
- Ground Stud (GS144)
- Generator Control Unit (GCU) 1 (A56)
- Variable Frequency Generator (VFG) 1 (G1)
- AC Power Center (ACPC) (A54)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter:
NOTE: The Generator ground stud connection may need to be visually inspected for signs of arcing.
A GCU patch cable (GSE REF # 24X-24-02) can be used to swap GCU 1, GCU 2, GCU 3, GCU 4 and the APU GCU into a different position (for troubleshooting only). You can monitor the GCU faults in CAIMS via the active fault page.
Quick Links:
| Removal of the Variable Frequency Generators (VFG) | AMM 24-21-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Variable Frequency Generators (VFG) | AMM 24-21-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Generator Control Units (GCU) | AMM 24-24-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Generator Control Units (GCU) | AMM 24-24-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the AC Power Center (ACPC) | AMM 24-51-00-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the AC Power Center (ACPC) | AMM 24-51-00-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Electrical Bonding - Adjustment/Test | SPM 51-80-00-05 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 [ Global Express ] [ G5000 ] [ Global XRS ] |
Troubleshooting Recommendations:
- At VFG 1, do a check of the output connections at the terminal block. Are the connections as shown in the table below?
Connection Color T1 White T2 Blue T3 Orange G Green - If YES, continue with next step.
- If NO, reconnect or repair as required.
- At the ACPC, do a check of the VFG input terminals at VFG 1 LCTA 1. Are the connections as shown in the table below?
Connection Color T1 White T2 Blue T3 Orange - If YES, continue with next step.
- If NO, reconnect or repair as required.
- Perform a bonding test of ground stud GS144
From To Expected result Result GS144 Ground <0.010 ohms - If the resistance value is higher than 0.010 ohms, repair ground stud.
- If the resistance value is good, continue with next step.
- Swap GCU 1 with GCU 2 (physically or using the GCU patch cable). Is the fault still present?
- If YES, continue with next step.
- If NO, replace defective GCU.
- Disconnect GCU 1 connector A56P1 and ACPC connector A54P6. Do a continuity checks as follow:
From To Result A56P1-A Ground A56P1-B Ground A56P1-C Ground - If there is continuity, repair defective wiring as required and do close out.
- If there is no continuity, continue with next step.
- Do a continuity checks as follow:
From To Result A56P1-A A54P6-A A56P1-B A54P6-B A56P1-C A54P6-C - If there is continuity, continue with next step.
- If there is NO continuity, repair defective wiring as required and do close out.
- Swap VFG 1 with VFG 2. Is the fault still present?
- If YES, continue with next step.
- If NO, replace defective VFG.
- Replace ACPC.
- Do close out.