W DOC AIRBUS | TSM A320F

Failure of the Automatic Switching Circuit of the AC Essential Bus

TASK 24-50-00-810-817-A
Failure of the Automatic Switching Circuit of the AC Essential Bus

1. Possible Causes
  • wiring
  • RELAY-ESS NTWK AUTO SWTG (17XC)
  • RELAY-BUS 2XP CTL (20XN2)
  • RELAY-BUS 1XP CTL (20XN1)
  • C/B [6XC]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 24-00-00-810-803-A
Circuit Breaker Tripped and/or C/B TRIPPED Warning
AMM 24-25-00-710-001
Operational Test of the AC Essential-Generation Switching
ASM 242501
ASM 242502
3. Fault Confirmation
Subtask 24-50-00-710-082-A
A. Test
Do the operational test of the AC essential generation switching AMM 24-25-00-710-001.
4. Fault Isolation
Subtask 24-50-00-810-068-A
A. If the test confirms the fault:
  • Do a check of the wiring ASM 242501 and ASM 242502 between:
    . Pin 2 of the C/B-CNTOR 3CX SW SPLY (5XC) and pin A/B1 of the RELAY-ESS NTWK AUTO SWTG (17XC)
    . Pin A/A of the CNTOR-AC ESS BUS SWITCHING (15XE) and pin A/B2 of the RELAY-ESS NTWK AUTO SWTG (17XC).
   (1) If the wiring is not correct:
  • Repair the wiring .
   (2) If the wiring is correct:
  • Do a check of the status of the C/B-ESS NTWK AUTO ALTN (6XC).
     (a) If the circuit breaker (6XC) is closed:
  • Do a check for 28VDC at pin 2 of the circuit breaker (6XC).
       1 If there is 28VDC:
  • Replace RELAY-ESS NTWK AUTO SWTG (17XC).
         a If the fault continues:
  • Do a check of the wiring ASM 242501 and ASM 242502 between:
    . Pin 2 of the C/B-ESS NTWK AUTO ALTN (6XC) and pin A/X1 of the RELAY-ESS NTWK AUTO SWTG (17XC)
    . Pin A/X2 of the RELAY-ESS NTWK AUTO SWTG (17XC) and pin A/A2 of the RELAY-BUS 2XP CTL (20XN2)
    . Pin A/A1 of the RELAY-BUS 2XP CTL (20XN2) and pin A/A2 of the RELAY-BUS 1XP CTL (20XN1)
    . Pin A/A3 of the RELAY-BUS 1XP CTL (20XN1) and the ground.

    * If the wiring is not correct:
    * - Repair the wiring .
    * If the wiring is correct:
    * - Replace RELAY-BUS 2XP CTL (20XN2).

    ** If the fault continues:
    ** - Replace RELAY-BUS 1XP CTL (20XN1).
       2 If there is no 28VDC:
  • Replace C/B [6XC] .
     (b) If the circuit breaker (6XC) is open:
5. Close-up
Subtask 24-50-00-710-083-A
A. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:26:57 UTC
"WTRUIB" 2025