AC power distribution (FO-8)

STUDENT GUIDE T-39N/G NATOPS

3. Six-mission inverters (provides power for mission AC bus) Note: inverters change DC

to AC

4. Engine-driven AC generators for forward windshield heat only.

G. AC power distribution (FO-8)

1. AC secondary bus: powered by either the main or stby inverter.

2. AC primary bus: powered by AC secondary bus or directly from the instrument

inverter if both main and stby fail.

3. Mission AC bus: powered from DC mission bus A (radar bus); AC MISSION PWR

switch ON/OFF.

4. #1 - 26 vac bus powered by AC primary bus (oil/hyd/oxy ind).

5. #2 - 26 vac bus powered by AC secondary bus (ADF/alt altr).

6. Four 5 vac indirect light busses powered by AC secondary bus.

H. AC power controls

1. Inverter switch

a. MAIN - essential bus powers main, standby, and instrument inverter, in that order.

(automatic fail down mode available)

b. STBY - essential bus powers stby inv only; no faildown mode.

c. OFF - no ess bus power (no AC power available).

d. MAIN INV FAIL light, STBY INV FAIL light.

2. Only instrument inverter available with battery power only.

I. AC power indicators

1. AC voltmeter: shows voltage of operating inverter.

2. AC INST PWR OFF light - Total loss of AC power, must be accompanied by MAIN and

STBY INV FAIL lights .

3. FT {fault) lights - phase A,B, C (two inverters per phase) - will illuminate if any of the

mission inverters in its particular phase fails; loss of two inverter on the same phase will shut

down the radar (the only way to tell if two inverters in one phase have failed is that the radar will

fail).

3-4

ELECTRICAL SYSTEM