Electrical

Question 1

How many independent generating systems provide primary AC power to the UH-60?

Answer 1

Primary AC power is provided by two independent generating systems.

Question 2

What APU generator output parameters does the APU Generator Control Unit (GCU) monitor?

Answer 2

The APU Generator Control Unit monitors:

over-voltage

under-voltage

feeder fault

under-frequency.

Question 3

What components does the No.1 Junction Box contain?

Answer 3

The No. 1 Junction Box contains:

No.1 generator contactor (K1)

current transformer (T-13)

current limiters (CL4, 5, 6)

one test receptacle.

Question 4

What is the purpose of the 60 ampere current limiters?

Answer 4

Protect the operating generator from excessive overloading during transfer operations.

Question 5

What external AC inputs does the external power monitor panel monitor?

Answer 5

The external power monitor panel monitors:

under-voltage

over-voltage

under-frequency

over-frequency

correct phase rotation

Question 6

The AC electrical system consists of what 3 types of power?

Answer 6

The AC electrical system consists of:

primary AC power

auxiliary AC power

external AC power

Question 7

The No. 1, No. 2, and the APU generator control units continuously monitor and regulate generator output to provide what 6 functions?

Answer 7

The No. 1, No. 2, and the APU generator control units continuously monitor and regulate generator output to provide:

voltage regulation

current regulation

over-voltage protection

under-voltage protection

feeder fault protection

under-frequency protection.

Question 8

The AC bus tie contactor (K-4) provides three-phase AC power from the . . or . ., to the . _._buses.

Answer 8

The AC bus tie contactor (K-4) provides three-phase AC power from the APU generator, or external AC power receptacle, to the AC primary buses.

Question 9

On the pilot circuit breaker panel, the AC essential bus transfer (XFER) relay (K-8) provides connection of . ., B phase power to the . . bus.

Answer 9

On the pilot circuit breaker panel, the AC essential bus transfer (XFER) relay (K-8) provides connection of 115 VAC, B phase power to the AC essential bus.

Question 10

What component supplies power to the DC essential bus when no AC electrical power is supplied to the helicopter buses?

Answer 10

The battery supplies power to the DC essential bus when no AC electrical power is supplied to the helicopter.

Question 11

What component provides connection between the No. 1 and the No. 2 DC primary buses?

Answer 11

The DC bus tie contactor (K15) provides connection between the No. 1 and the No. 2 DC primary buses.

Question 12

What is the percentage of charge in the battery that allows the DC ESS BUS OFF capsule to illuminate?

Answer 12

The charge in the battery supplying the DC ESS BUS falls to 35%, will cause the DC ESS BUS OFF capsule to illuminate.

Question 13

What parameters does the Battery Analyzer/Conditioner not monitor?

Answer 13

The Battery Analyzer/Conditioner monitors Battery Voltage, temperature conditions, and charging circuit for battery charging.

Question 14

What component provides primary DC power for helicopter equipment?

Answer 14

The converter provides primary DC power for helicopter equipment.

Question 15

The primary DC system consists of what?

Answer 15

The primary DC system consists of:

two converters, supplied from the AC power system, and associated caution/advisory capsules.

Question 16

The converters operate from . / VAC. three-phase, . Hz. power and provide outputs of . VDC. at no load to . VDC. at . AMPS.

Answer 16

The converters operate from 115/200 VAC, three-phase, 400 Hz power and provide outputs of 31 VDC at no load to 25 VDC at 200 amperes.

Question 17

The DC bus tie current limiter (CL7), in the No. . . junction box, is a _. ._fuse that protects the connection between the . . and the . . primary DC buses.

Answer 17

The DC bus tie current limiter (CL7), in the No. 1 junction box, is a 100 ampere fuse that protects the connection between the No. 1 and the No. 2 primary DC buses.

Question 18

The current limiter (CL7) operates when one primary DC bus is supplying the other DC primary bus as a result of a . . caused by a load short-circuits.

Answer 18

The current limiter (CL7) operates when one primary DC bus is supplying the other DC primary bus as a result of a converter failure caused by a load short-circuits.

Question 19

The battery supplies power to what….when no AC power is supplied to the helicopter buses?

Answer 19

The battery supplies power to the DC essential bus when no AC power is supplied to the helicopter buses.

Question 20

The battery always supplies what bus?

Answer 20

The battery always supplies the battery utility bus.

Question 21

The No. 1 and No. 2 converters receive three-phase AC power from the No. 1 and No. 2 what? With both converters operating normally, the No. 1 converter supplies the . . bus and the No. 2 converter supplies the . . bus.

Answer 21

The No. 1 and No. 2 converters receive three-phase AC power from the No. 1 and No. 2 AC primary buses. With both converters operating normally, the No. 1 converter supplies the No. 1 DC primary bus and the No. 2 converter supplies the No. 2 DC primary bus.

Question 22

If the No. 1 converter fails and its output drops to zero, No. 1 DC primary bus contactor (K16) . . DC power from the No. 2 DC primary bus is applied through the normally closed auxiliary contacts of contactor K16 to . . DC bus tie contactor (K15). With contactor K15 energized, DC power from the No. 2 DC primary bus is applied through the . . to supply the No. 1 DC primary bus.

Answer 22

If the No. 1 converter fails and its output drops to zero, No. 1 DC primary bus contactor (K16) de-energizes. DC power from the No. 2 DC primary bus is applied through the normally closed auxiliary contacts of contactor K16 to energize DC bus tie contactor (K15). With contactor K15 energized, DC power from the No. 2 DC primary bus is applied through the 100 amp current limiter to supply the No. 1 DC primary bus.

Question 23

The . . AC power is applied from the external power receptacle through the normally closed main contacts of contactor K3, the energized main contact of contactor K4, and the normally closed main contacts of contactor K2 to supply the . . primary bus. The No. 1 AC primary bus is supplied through current limiters . . and the normally closed main contacts of contactor K1. The No. 1 AC primary bus supplies 115 VAC, . . power, through the AC ESNTL BUS SPLY circuit breaker, to the coil and contacts of AC essential bus XFR relay K8. With relay K8 energized, and 115 VAC, B phase power is supplied to the AC essential bus. The . . applies 115 VAC, B phase power to an autotransformer that supplies 26 VAC to navigation instrument loads.

Answer 23

The three-phase AC power is applied from the external power receptacle through the normally closed main contacts of contactor K3, the energized main contact of contactor K4, and the normally closed main contacts of contactor K2 to supply the No. 2 AC primary bus. The No. 1 AC primary bus is supplied through current limiters. CL1, CL2, and CL3 and the normally closed main contacts of contactor K1. The No. 1 AC primary bus supplies 115 VAC, B phase power, through the AC ESNTL BUS SPLY circuit breaker, to the coil and contacts of AC essential bus XFR relay K8. With relay K8 energized, and 115 VAC, B phase power is supplied to the AC essential bus. The AC essential bus applies 115 VAC, B phase power to an autotransformer that supplies 26 VAC to navigation instrument loads.

Question 24

The battery switch is what kind of switch?

Answer 24

2 poles

Question 25

Primary source of power for AC ess bus is from what?

Answer 25

B phase #1 AC primary bus

Question 26

•When the generator control switch is placed to TEST, system operation is the same as for the ON position, except that generator contactor K1 remain de-energized. Power from the GCU flows through the normally closed contacts of K1, to illuminate the No. 1 Generator capsule on the Caution/Advisory Panel. The GCU test relay, which is located inside the GCU, is energized. With the GCU test relay energized, its contacts open and the caution/advisory panel GEN capsules go off. The generator outputs are not applied to the AC buses, but are applied to the test receptacles for monitoring.

Answer 26

•When the generator control switch is placed to TEST, system operation is the same as for the ON position, except that generator contactor K1 remain de-energized. Power from the GCU flows through the normally closed contacts of K1, to illuminate the No. 1 Generator capsule on the Caution/Advisory Panel. The GCU test relay, which is located inside the GCU, is energized. With the GCU test relay energized, its contacts open and the caution/advisory panel GEN capsules go off. The generator outputs are not applied to the AC buses, but are applied to the test receptacles for monitoring.

Question 27

•With the No. 1 and No. 2 generators OFF and the APU generator operating at its rated value, APU/external power contactor (K3) is energized. DC voltage is applied through a blocking diode and the normally closed auxiliary contacts of No. 2 and No. 1 generator contactors (K2 and K1), to energize AC bus tie contactor (K4). The three-phase AC output of the APU generator is applied through the energized main contacts of contactors K3 and K4, and the normally closed main contacts of contactor K2, to supply the No. 2 AC primary bus. The No. 1 AC primary bus is supplied through current limiters and the normally closed main contacts of contactor K1.

Answer 27

•With the No. 1 and No. 2 generators OFF and the APU generator operating at its rated value, APU/external power contactor (K3) is energized. DC voltage is applied through a blocking diode and the normally closed auxiliary contacts of No. 2 and No. 1 generator contactors (K2 and K1), to energize AC bus tie contactor (K4). The three-phase AC output of the APU generator is applied through the energized main contacts of contactors K3 and K4, and the normally closed main contacts of contactor K2, to supply the No. 2 AC primary bus. The No. 1 AC primary bus is supplied through current limiters and the normally closed main contacts of contactor K1.

Question 28

•If the No. 1 generator fails, the No. 2 generator supplies the No. 1 AC primary bus through current limiters and the normally closed main contacts of No. 1 generator contactor (K1).

Answer 28

•If the No. 1 generator fails, the No. 2 generator supplies the No. 1 AC primary bus through current limiters and the normally closed main contacts of No. 1 generator contactor (K1).

Question 29

•With No. 1 GENERATORS switch OFF, the No. 1 generator output does not build up. The No. 1 generator contactor (K1) is de-energized, and voltage flows through the normally closed auxiliary contacts of K1 to illuminate the No. 1 GEN capsule on the caution/advisory panel. The three-phase output of the No. 2 generator is applied from the No. 2 AC primary bus, through current limiters CL1, 2, and 3, and through the normally closed main contacts of the No. 1 generator contactor (K1), to supply the No. 1 AC primary bus. With the failure of the current limiters 1, 2, and 3, voltage is unable to flow from the No. 2 AC Primary Bus to supply the No. 1 AC Primary Bus.

Answer 29

•With No. 1 GENERATORS switch OFF, the No. 1 generator output does not build up. The No. 1 generator contactor (K1) is de-energized, and voltage flows through the normally closed auxiliary contacts of K1 to illuminate the No. 1 GEN capsule on the caution/advisory panel. The three-phase output of the No. 2 generator is applied from the No. 2 AC primary bus, through current limiters CL1, 2, and 3, and through the normally closed main contacts of the No. 1 generator contactor (K1), to supply the No. 1 AC primary bus. With the failure of the current limiters 1, 2, and 3, voltage is unable to flow from the No. 2 AC Primary Bus to supply the No. 1 AC Primary Bus.

Question 30

•If a failure occurs to the AC essential bus, the AC ESS BUS OFF capsule on the caution/advisory panel will light. Also, voltage will be removed from the 26 VAC bus.

Answer 30

•If a failure occurs to the AC essential bus, the AC ESS BUS OFF capsule on the caution/advisory panel will light. Also, voltage will be removed from the 26 VAC bus.