NAMTS GAS TURBINE REPAIR TECHNICIAN V-651-4140 INFORMATION SHEET 131.64 ...

NAMTS GAS TURBINE REPAIR TECHNICIAN PROCESS 131.64

V-651-4140 Sheet 1 of 28

INFORMATION SHEET 131.64-2 POWER AND TRANSMISSION FUNDAMENTALS

A. INTRODUCTION

This lesson is an introduction to the equipment and associated components that transmit power developed by the main propulsion engines to the propulsors. Personnel shall become knowledgeable of this information to be proficient as a gas turbine repair technician and to provide reliable support in shipboard repair and maintenance efforts.

B. REFERENCES

1. Naval Sea Systems Command (NAVSEA) S9234-GA-GTP-010, Propulsion Plant Manual, Propulsion Plant System for DDG 51 Class Ships

2. NAVSEA 0901-LP-430-0012, Naval Ships' Technical Manual (NSTM) Chapter 243, Propulsion Shafting

3. NAVSEA S9086-HN-STM-000, NSTM Chapter 244, Propulsion Bearings and Seals

4. Naval Education and Training (NAVEDTRA) 14113A Gas Turbine Systems Technician (Electrical/Mechanical) GSE/GSM

5. NAVEDTRA 14104A, Fireman

C. INFORMATION

1. Introduction.

a. This lesson is an introduction to the equipment and associated components that transmit power developed by the main propulsion engines to the propulsors. Personnel shall become knowledgeable of this information to be proficient as a gas turbine repair technician and to provide reliable support in shipboard repair and maintenance efforts.

2. Safety Precautions.

a. Specific warnings, cautions, and notes regarding the system and equipment appear throughout the technical manuals following paragraph headings and immediately preceding the text to which they apply.

1) Warning - Used to draw special attention to potential hazardous situations which if not avoided could result in minor personal injury, serious injury, or death.

2) Caution - Used to draw special attention to anything that could damage equipment or cause the loss of data and includes what could happen if the caution is ignored.

3) Note - Used to highlight essential procedure(s) by visually distinguishing it from the rest of the text and can contain any type of information except safety information.

FOR TRAINING USE ONLY

NAMTS GAS TURBINE REPAIR TECHNICIAN PROCESS 131.64

V-651-4140 Sheet 2 of 28

3. Power Transmission.

a. Ship propulsion is achieved through the conversion, transmission, and utilization of energy in a sequence of events that includes the development of power in a prime mover, the transmission of power to the propellers, the development of thrust on the working surfaces of the propeller blades, and the transmission of thrust to the ship's structure in order to move the ship through the water, as shown in Figure 131.64-2.1.

Figure 131.64-2.1: USS Curtis Wilbur (DDG 54)

1) When the Gas Turbine Engine (GTE), prime mover, is coupled to the Main Reduction Gear (MRG), it transmits its rotation and torque through a series of gears to reduce its speed.

FOR TRAINING USE ONLY

NAMTS GAS TURBINE REPAIR TECHNICIAN PROCESS 131.64

V-651-4140 Sheet 3 of 28

2) This rotation and torque are then relayed to the propeller through the propulsion shafting and develops thrust, the reactive force, as shown in Figure 131.64-2.2.

Figure 131.64-2.2: Propulsion Components (Typical) b. The power train of gas turbine powered ships consists of one or more of the following

components: 1) Reduction gear. 2) Clutch. 3) Oil Distribution (OD) box. 4) Propulsion shafting system. 5) Hub blade assembly. 6) Water jet. 4. Power Transmission Terms.

FOR TRAINING USE ONLY

NAMTS GAS TURBINE REPAIR TECHNICIAN PROCESS 131.64

V-651-4140 Sheet 4 of 28

a. Drive mechanism - The basic characteristics of a propulsion unit usually make it necessary for the drive mechanism to change both the speed and the direction of shaft rotation, as shown in Figure 131.64-2.3.

Figure 131.64-2.3: Main Reduction Gear (MRG) (Typical)

1) A drive mechanism coupled to the driven member by gears or belts is an indirect drive. a) The engine in many installations includes a device that permits a speed reduction from the engine to the propeller shaft so that both the engine and the propeller may operate efficiently. This device is a combination of gears and is called a reduction gear.

2) A drive mechanism coupled directly to the driven member is a direct drive. b. Feet of pitch - The local pitch indicator is a pointer which slides along a scale

calibrated in percent of pitch and feet of pitch. c. Frozen clutch - When a clutch fails to disengage, it is frozen. Failure of the clutch to

disengage may be caused by a defective clutch mechanism or by water absorbed in the material that lines the clutch plates. When a clutch becomes frozen, inspect the operating mechanism.

FOR TRAINING USE ONLY

NAMTS GAS TURBINE REPAIR TECHNICIAN PROCESS 131.64

V-651-4140 Sheet 5 of 28

d. Lock shaft - The shaft locking device, as shown in Figure 131.64-2.4, locks to prevent the shaft from rotating.

1) There may be times when it is necessary to stop and lock the main propeller shaft for an emergency or casualty.

2) Some ships have the shaft locking device incorporated into the turning gear assembly and other classes of ships have the shaft locking device as a separate component.

3) The best way to lock a propeller shaft while the ship is underway is to wait for the shaft to stop, engage the turning gear, and then apply the brake.

Figure 131.64-2.4: Shaft Locking Device (Typical) FOR TRAINING USE ONLY

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