DC power indicators

STUDENT GUIDE T-39N/G NATOPS

b. ESS - manual connection of batteries to essential bus with dual gen fail (only to be

selected if auto transfer fails).

c. OFF - disconnects battery bus from paralleling bus.

3. DC gen switches: generators online at 40% rpm provided the Electrical Master is ON,

Fire Pull handle is in, or the Engine Start (ground or air) is off. Positions are ON-OFF-

RESET.

4. DC MISSION PWR switch:

a. NORM - power to DC mission bus A and B from essential bus.

b. EMER - power to DC mission bus A if single gen failed.

c. OFF - removes power from both DC mission bus A and B.

5. Battery isolation switches:

a. OVERRIDE - Used during 2nd engine start with battery switch off (allows the battery

to start the 2nd engine while the 1st engine generator powers the paralleling bus).

b. ISOL - Removes the respective battery from the battery bus via the isolation relay.

c. NORM - Normal connection of batteries to battery bus.

D. DC power indicators

1. Voltmeter - shows essential bus voltage unless PUSH LH/RH GEN VOLT is depressed.

2. Loadmeter - LH/RH, should be within 1 division (after engine start, up to 30 min allowed

to stabilize).

Caution lights single DC GEN OFF - reset ( Gen will kick off line btwn 31-33v)

LH/RH DC GEN HOT - gen OFF (155 C)

BATT HOT - Battery switch off (150 F) ESS BUS CB OUT - extra loads OFF

MISSION A or B FAIL - select EMER if the radar is desired.

E. Single DC Generator Ops

1. Max load on operating generator =

.8 - sea lvl to 30,000'

.5 - 30,000' to 40,000'

2. Maintain .65M for cooling, max op altitude = 40,000

F. AC power source

1. Main or Stdby inverter (1500 or 1250 v-a, 115 + 8 volts)

2. Instrument inverter (1000 v-a, 115 + 8 volts)

ELECTRICAL SYSTEM 3-3