W DOC AIRBUS | TSM A320F

Loss of the GEN 1 (Failure of the Wiring of the Current Transformers 42XU1 and 42XU3)

TASK 24-20-00-810-821-A
Loss of the GEN 1 (Failure of the Wiring of the Current Transformers 42XU1 and 42XU3)

1. Possible Causes
  • Generator 1 contactor-module 30XN1
  • Terminal block 1999VT
  • Terminal block 400VT1
  • Terminal blocks T1, T2, T3 and N of IDG 1
  • Receptacle 400VC1
  • wiring
  • [4000XU1]
  • GCU-1 [1XU1]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 24-21-51-000-040
Removal of the Integrated Drive Generator - IDG 1(2)
AMM 24-21-51-400-040
Installation of the Integrated Drive Generator - IDG 1(2)
ASM 242201
AMM 24-22-17-000-001
Removal of the AC Current Transformers
AMM 24-22-17-400-001
Installation of the AC Current Transformers
AMM 24-22-34-000-001
Removal of the GCU-1(2)
AMM 24-22-34-400-001
Installation of the GCU-1(2)
AMM 24-41-00-740-004
Operational Check of the GPCU via the CFDS
AMM 24-41-00-861-002
Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002
De-energize the Aircraft Electrical Circuits Supplied from the External Power
AMM 31-60-00-860-001
EIS Start Procedure
AMM 71-00-00-710-003
Engine Automatic Start
AMM 71-00-00-710-028
Engine Shutdown
3. Fault Confirmation
Subtask 24-20-00-700-065-A ** ON A/C NOT FOR ALL
A. Test
Not applicable.
NOTE: As the GEN 1 was set to OFF because of a true failure, the fault confirmation is not necessary.
4. Fault Isolation
Subtask 24-20-00-810-065-B ** ON A/C NOT FOR ALL
A. If the fault symptom is identified by the CFDS message CHECK CT 42XU1 42XU3 GCU 1 PIN B11A TO B11D WIRING and the upper ECAM DU warning GEN 1 FAULT:
   (1) Do a visual inspection and repair or replace as necessary:
  • Generator 1 contactor-module 30XN1
  • Terminal block 1999VT
  • Terminal block 400VT1
  • Terminal blocks T1, T2, T3 and N of IDG 1
  • Receptacle 400VC1 .
   (2) Do a check of the wiring for open circuit between respectively:
. the pins A/1, A/2, A/3, A/4 of the current transformer 42XU3 and respectively:
.. the pins B/11A, B/11B, B/11C, B/11D of the GCU 1,
.. the pins A/1, A/2, A/3, A/4 of the current transformer 42XU1,
. the pins A/1, A/6, A/7, A/8 of the IDG 1 to respectively the pins B/13D, B/13A, B/13B, B/13C of the GCU 1 ASM 242201.
     (a) If there is no continuity:
  • Repair the wiring.
     (b) If the wiring is correct:
Do an impedance check of the coils of the current transformers 42XU1 and 42XU3 between pin A/4 and successively pins A/1, A/2 and A/3.
NOTE: The normal impedance is 10.15 Ohms plus or minus 3.45 Ohms.
       1 If the impedance is out of tolerance:
       2 If the impedance is correct:
  • Make sure, on current transformers 42XU1 and 42XU3 that the pin A/6 is electrically insulated from pins A/1, A/2, A/3 and A/4.
         a If not insulated:
         b If insulated:
  • Do an impedance check of the coil of the IDG 1 current transformer from the pin A/1 to succesively pins A/6, A/7 and A/8.
NOTE: The normal impedance is 26 Ohms plus or minus 2 Ohms at 25°C.
* if the impedance is out of tolerance:
- Replace [4000XU1] AMM 24-21-51-000-040 and AMM 24-21-51-400-040.
* if the impedance is correct:
- Replace GCU-1 [1XU1] AMM 24-22-34-000-001 and AMM 24-22-34-400-001.
Subtask 24-20-00-860-080-A ** ON A/C NOT FOR ALL
B. Do this operational test to make sure that the system operates correctly.
   (1) Aircraft Maintenance Configuration
     (a) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
     (b) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.
   (2) On the ELEC panel 35VU:
  • push, release and push again the GEN 1 pushbutton switch (3XU1).
   (3) Do the operational check of the GPCU with the CFDS AMM 24-41-00-740-004.
   (4) Start the engine 1 AMM 71-00-00-710-003.
Subtask 24-20-00-710-065-A ** ON A/C NOT FOR ALL
C. Do this test:
ACTION
RESULT
On the ECAM control panel:
  • get the ELEC page.
On the lower ECAM display unit:
  • the correct electrical parameters of GEN 1 are shown and AC 1 busbar is supplied by GEN 1.
5. Close-up
Subtask 24-20-00-860-081-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
   (1) Stop the engine 1 AMM 71-00-00-710-028.
   (2) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
   (3) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.
[Rev.8 from Aug 2018] 2026.04.04 04:26:11 UTC
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