1. UH-60 IPC/MOI
CW2 JAMES THOMAS

2. ELECTRICAL SYSTEM FIRE DETECTION AND EXTINGUISHING SYSTEMS
UH-60
ELECTRICAL SYSTEM
FIRE DETECTION AND
EXTINGUISHING SYSTEMS

3. REFERENCES
OPERATOR’S MANUAL
FLIGHT LINE SUPPLEMENT
STUDENT HANDOUT

4. ELECTRICAL SYSTEM OVERVIEW
AC SYSTEM AND COMPONENTS
DC SYSTEMS AND COMPONENTS
EP’s

5. Alternating Current is the primary source of power.

6. The primary electrical system consists of two independent systems, each of which is capable of supplying the total helicopter power requirements.

7. COMPONENTS OF AC SYSTEM
TWO MAIN GENERATORS
ONE AUXILIARY GENERATOR
ONE EXTERNAL RECEPTACLE
THREE GENERATOR CONTROL UNITS
ONE EXTERNAL POWER MONITOR
TWO AC PRIMARY BUSES
ONE AC ESSENTIAL BUS
SIX CURRRENT LIMITERS

8. GENERATORS
The two main generators are identical and interchangeable. They are located on the right and left hand transmission accessory gearboxes.

9. The main generators are: three phase, 115/200 volt ac, 400 Hz, OIL COOLED generators.

10. APU GENERATOR
The auxiliary generator is located on the auxiliary power unit.

11. The auxiliary or APU generator is a three phase, 115 volt ac, 400 Hz, AIR COOLED generator. It provides AC power for ground operations and for in-flight emergencies.

12. Each generator is capable of assuming another generators load in case of a failure.

13. This system works in priority;
The main generators have priority over the APU generator and the APU generator has priority over external power.

14. GENERATOR CONTROL UNIT
A GCU controls voltage output and provides circuit protection.

15. There are three Generator Control Units in this system:
one for each generator.

16. FUNCTIONS OF THE GCU Voltage Regulation Under Voltage Protection
Over Voltage protection
Under Frequency Protection
Feeder Fault

17. AC BUSES #1 AC primary bus is powered by the #1 main generator.
AC essential bus is normally powered by the #1 primary bus.

18. CURRENT LIMITERS Six Current Limiters Three for each Primary Bus
60 Amp
Works like a fuse - excessive amps melt metal and open circuit that goes across the current limiter

19. EXTERNAL POWER External Power Receptacle Third Priority
External Power Monitor

20. EXTERNAL POWER MONITOR
Under Voltage Protection
Over voltage protection
Under frequency Protection
Over frequency Protection
Correct Phase Rotation

21. DIRECT CURRENT SYSTEM

22. DC SYSTEM COMPONENTS BATTERY CHARGER/ANALYZER TWO DC PRIMARY BUSES
ONE DC ESSENTIAL BUS
TWO AC/DC CONVERTERS
CURRENT LIMITER

23. CONVERTERS Two 200 amp air cooled converters
Input voltage… 3 phase,115 volt ac, 400 Hz
Output voltage… 28 volts dc

24. DC BUSSES 2 DC PRIMARY BUSSES 1 DC ESSENTIAL BUS 1 BATTERY UTILITY BUS
1 BATTERY BUS

25. When battery is sole source of DC power….
DC BUSSES
When battery is sole source of DC power….

26. Battery Utility Bus is hot when battery is connected.
Battery Bus is hot when battery is connected and battery switch is on.
DC Essential Bus is hot when battery is connected, switch is on and 35% charge.

27. CURRENT LIMITER One 100 amp current limiter
Provides protection to circuits in the event of excessive amperage or draw.

28. The battery is 24 volts dc, 5.5 amp hours, with 20 cells.
(Nicad only)

29. The battery is the secondary or emergency source of DC power.

30. When the battery is the sole source of DC power, it is limited to 22 minutes of day operation and 14 minutes of night operation at 80% capacity.

31. CHARGER ANALYZER
Provides a constant charge to the battery when the #2 AC primary and #2 DC primary busses are energized.
Analyzes the battery, controls Battery Low and Fault Caution Lights, and disengages the DC essential bus when battery capacity drops below 35%.

34. WHICH LIGHTS ILLUMINATE WHEN THE BATTERY SWITCH IS PLACED ON?

35. #1 CONV AND #2 CONV
AC ESS BUS OFF
BOOST SERVO OFF
STABILATOR
SAS OFF

36. WHEN DOES THE BATT LOW CAUTION LIGHT ILLUMINATE?

37. THE BATT LOW CAUTION LIGHT ILLUMINATES WHEN THE BATTERY STATE OF CHARGE IS AT OR BELOW 40% CAPACITY.

38. EMERGENCY PROCEDURES

39. MASTER CAUTION
#1 GEN

40. 9.26.2 #1 OR #2 GEN Caution Light On
1. Affected GENERTORS switch RESET; then ON if caution light remains on:
Affected GENERATORS switch OFF

41. MASTER CAUTION
#1 CONV
#2 CONV
AC ESS BUS OFF
STABILATOR

42. 9.26.1 #1 and #2 Generator failure
SAS 1 switch - press off.
Airspeed - Adjust ( 80 KIAS or less )
GENERATORS NO. 1 and NO. 2 switches - RESET; then ON If caution lights remain on:
GENERATORS NO. 1 and NO. 2 SWITCHES - OFF.
EMER APU START
SAS 1 switch - ON
LAND AS SOON AS PRACTICABLE.

43. FIRE DETECTION AND EXTINGUISHING SYSTEMS

44. OVERVIEW
DEFINITIONS
COMPONENTS
OPERATION
EP’s
WARNINGS

45. FIRE DETECTION SYSTEM
The fire detection system provides fire warning to the cockpit in case of fire in either main engine or APU compartments.

46. The system consists of the following components.
5 Radiation Sensing Flame Detectors
3 Control Amplifiers
3 Arming Levers
Fire Detector Test Panel

47. FIRE EXTINGUISHING SYSTEM
A high-rate discharge extinguishing system provides a two shot, main and reserve capability to either main engine compartment or APU compartment.

48. The Fire Extinguishing system consists of the following components
3 Fire Extinguishing Arming Levers
Fire Extinguisher Control Panel
High Rate Discharge System
Omni-directional inertial switch

49. System Sequence Fire Master Caution and Warning light
T-Handle Pull Aft
Fire Extinguisher Switch
High-Rate Discharge

50. Engine Fire in Flight.
ENG POWER CONT lever ( affected engine ) - OFF.
ENG EMER OFF handle - pull.
FIRE EXTGH switch - MAIN/RESERVE as required.
LAND AS SOON AS POSSIBLE.

51. WARNING
If AC electrical power is not available, only the reserve fire bottle can be discharged and fire extinguishing capability for the #2 engine will be lost.

52. REVIEW
DEFINITIONS
COMPONENTS
OPERATION
EP’s
WARNINGS