BOEING 737 NG ELECTRICAL SYSTEM

The purpose of the AC ground service bus is to power: The cabin lighting. The utility outlets. The battery charger. All the above.

The TR´s (Transformer rectifier) convert: 115 volts DC to 28 volts AC. 115 volts AC to 28 volts AC. 115 volts AC to 28 volts DC. 115 volts DC to 28 volts DC.

Which is the power source for the AC standby bus?. Transfer bus 1 under normal conditions. Transfer bus 2. AC main bus 1. Battery Bus through the Static Inverter under normal conditions.

A high oil temperature in the IDG would cause an automatic disconnect of the IDG. True. False.

The cross bus tie relay: Must be manually opened using the BUS TRANSFER Switch during a Flight Director approach. Normally powers the Battery Charger and backs-up TR units 1 and 2 through a diode. Opens up if BUS TRANSFER switch is moved to OFF. Will trip off when AC volts reaches 26 volts (plus or minus 4 volts) as displayed on the AC voltmeter.

Illumination of the GND POWER AVAILABLE light indicates: Ground power is connected and meets airplane power quality standards. Ground power is connected however no airplane power quality is measured. The Ground Service Bus is powered by a ground power supply. The external power bus is powered by a ground power supply.

For ground service, a ground service switch is placed: On aft overhead panel on the Flight Deck. On aft attendant´s panel. On forward attendant´s panel. On external receptacle on the right side of the aircraft exterior.

One basic rule of operation for the B737 electrical system is: All generator bus sources can be automatically connected by the Standby Power System. There is no paralleling of the AC power sources. The aircraft must be on ground and GPU connected. An AC power source may be used in parallel with a DC power source.

Illumination of the BAT DISCHARGE light indicates: The battery is being overcharged. Excessive battery discharge is detected with the battery switch ON. The DC meter is in the BAT position with the battery switch ON. The battery bus is not powered.

In the event that the airplane battery is depleted, the APU can be started using DC external power. True. False.

Illumination of the blue GEN OFF BUS light indicates: The associated generator bus is not powered. The associated transfer bus is not powered. The IDG is not supplying power to its associated transfer bus. The generator is not supplying power to its associated generator bus.

Which equipment management the logic of the lights in the electrical panel : SPCU. GCU. AGCU. SCU AND SPU.

Illumination of the DRIVE light indicates: IDG failure. IDG automatic disconnect due to high oil temperature. IDG disconnected through the drive disconnect switch. Any of the above.

The TR UNIT will illuminate in flight if: Any TR unit fails. TR1 fails or TR2 and TR3 fail. TR2 Fails. TR3 Fails.

The ELEC light will illuminate in flight if: A fault exists in the AC or Standby power system. A fault exists in the DC or Standby system. A fault exists in the AC, DC or the Standby system. The ELEC light only operates on the ground.

With external DC power connected to the external DC power receptacle: The APU can be started using DC external power. The battery is paralleled with the DC External power source. All circuits normally powered by the battery are powered. There is no external DC power receptacle.

The main battery charger is powered through: DC bus 1. AC ground service bus 2. AC main bus 1. Transfer Bus 1.

The electrical system incorporates an automatic load shedding feature. What is the first bus that is shed?. Galleys on transfer bus 1 are shed first. Galleys on transfer bus 2 are shed first. The AC standby bus is shed first. None of above.

The electrical system incorporates an automatic load shedding feature. What is the second bus that is shed?. Galleys on transfer bus 1. Galleys on transfer bus 2. The AC ground service bus. The AC standby bus.

After an overload situation has been resolved, how do you recover the galley buses?. It happens automatically. Move the galley power switch to OFF then ON. A ground engineer should reselect the appropriate switch in the E/E.

Once disconnected, the IDG can be reconnected in flight. True. False.