737 CL + NG Electrical

Question 1

(CL) What does the “STANDBY POWER OFF” light tell you?

Answer 1

AC standby bus is inactive.

Question 2

(CL) On the ground, if you lose all AC power with the STANDBY POWER switch in AUTO, what happens?

Answer 2

No automatic switching; AC and DC standby power buses are unpowered.

Question 3

(CL) What happens if you move the BUS TRANS switch to OFF?

Answer 3

Isolates transfer busses by preventing operation of the bus transfer relays, and opens TR3 disconnect relay. Prevents the battery charger from switching to its alternate source of power, main bus 2.

Question 4

(NG) What happens if you move the BUS TRANSFER switch to OFF?

Answer 4

OFF – isolates AC transfer bus 1 from AC transfer bus 2 if one IDG is supplying power to both AC transfer busses
• DC cross tie relay opens to isolate DC bus 1 from DC bus 2.

Question 5

(CL) In flight; if the APU is powering one generator bus and you move the other APU GEN switch to ON, what will happen?

Answer 5

The second generator bus will not connect to the APU generator.

Question 6

(CL) What does the GROUND SERVICE switch do?

Answer 6

Provides manual control of ground service bus. Enables servicing airplane using external power without activating generator busses.
• ON – connects the ground service bus to the external AC bus. Trips off when the GRD PWR switch is ON
• OFF – disconnects external AC bus from the ground service bus.

Question 7

(CL) Is it possible to connect external power with the battery switch OFF?

Answer 7

No

Question 8

(CL) On the generator drive oil temperature indicator, readings above ( ? ) deg. C indicate excessive generator load or poor condition of the drive.

Answer 8

20C