Propulsion/ Aux Turbines & Reduction Gears/ Propellers

Question 1

what type of turbine blading is used for installation in circumferential groves?

Answer 1

tee-rot blading

Question 2

outside dovetail type turbine is used with what type of entry?

Answer 2

circumferential entry

Question 3

how is axial-entry type turbine blading secured to the rotor wheel (disk)?

Answer 3

by a platform interlock, pin or key

Question 4

end play cold thrust bearing clearance is defined as?

Answer 4

the distance the thrust collar can be moved between the forward and aft thrust bearing faces without applying appreciable load to either face

Question 5

typical end play with the engine cold is?

Answer 5

.008 - .014 inch

Question 6

the term total float clearance refers to what?

Answer 6

the axial clearance taken with the thrust bearing shoes removed

Question 7

when taking bearing depth micrometer readings, bridge gage readings and the taking of leads the lube oil system should be secured when?

Answer 7

24 hours prior to taking the readings

Question 8

what material are oil deflectors manufactured from?

Answer 8

aluminum or bronze

Question 9

what NSTM covers general information on SSTG turbines?

Answer 9

NSTM 231

Question 10

what two types of impulse turbines used exclusively for auxiliary use?

Answer 10

curtis-rateau or straight rateau

Question 11

the lube oil cooler should be bypassed on an operating auxiliary turbine until the discharge oil temperature reads what?

Answer 11

100 degrees F

Question 12

if a metal edge filter is installed in the oil line on an auxiliary turbine, the filter handle shall be turned how many ties per watch?

Answer 12

at least once per watch

Question 13

when starting SSTG’s what is the minimum allowable lube oil temperature?

Answer 13

60 degrees F

Question 14

after starting an SSTG, at what vacuum is the generator brought up to speed?

Answer 14

15 inches

Question 15

what is the major difference critical RPMs on an SSTG compared to a auxiliary turbine?

Answer 15

critical SSTG RPMs are achieved at 20-25 percent below normal operating speed, auxiliary turbine critical RPM’s is achieved above normal operating pressure

Question 16

temporary distortion of the SSTG rotor after the numerous start/stop episodes is known what?

Answer 16

a bowed motor

Question 17

what must the lube oil temperature be on a SSTG prior to bringing it up to operating speed?

Answer 17

100 degrees F

Question 18

SSTG gland sealing steam pressure has a range of what?

Answer 18

1/2 - 2 psi

Question 19

speed limiting governors installed on auxiliary turbines are deigned to limit maximum speed to what percentage of designed speed?

Answer 19

110 percent

Question 20

on an SSTG turbine, what action must be taken if clearance between the nozzle diaphragm and the adjacent row of blades is outside the limits prescribed by the manufacturer?

Answer 20

adjusts the position of the rotor by changing the filler piece in the thrust bearing

Question 21

SSTGs are fitted with what type of governor?

Answer 21

constant speed

Question 22

on an SSTG, what protects the turbine casing from excessive pressure?

Answer 22

back pressure trip

Question 23

what is installed on non condensing turbines to protect the turbine casing from excessive pressure?

Answer 23

combination exhaust relieve valves

Question 24

the combination exhaust relief valve is set to lift at what range?

Answer 24

2 - 3 psi above exhaust line pressure

Question 25

what is installed upstream in the steam line of the governor to protect an SSTG turbine from debris?

Answer 25

steam strainer

Question 26

who is the approving authority for turbine casing and rotor weld repairs

Answer 26

NAVSEA

Question 27

how is a damaged auxiliary turbine blade removed when it is not feasible or the situation does not permit reblading?

Answer 27

the damaged blade and the blade diametrically opposite must be cut off at the junction of the vane portion and the root and the root checked for balance if practical

Question 28

turbine failure must be reported to whom?

Answer 28

NAVSEA

Question 29

how are failed turbine parts documented?

Answer 29

word description and photographs

Question 30

turbine blading erosion is usually limited to what area?

Answer 30

the blade or nose tips of the last few rows of low pressure turbine

Question 31

when steam is being admitted to the propulsion turbine the rotor should not remain idle for more than how many minutes?

Answer 31

5 minutes

Question 32

when warning a propulsion turbine, the turbine should be rotated with steam at what interval?

Answer 32

every 2 - 3 minutes

Question 33

what is the quickest means to determine any change in the relief position of the propulsion turbine rotor caused by bearing wear?

Answer 33

depth gauge micrometer

Question 34

what maintains the axial position of the propulsion turbine rotor?

Answer 34

thrust bearings

Question 35

what maintains the radial position of the propulsion turbine rotor?

Answer 35

journal bearings

Question 36

how is the propulsion turbine bearing wear determined?

Answer 36

by measuring the outside of the diameter of the rotor journal and the inside diameter of the bearing to determine actual oil clearances. the difference between the old and the new clearance readings will be the amount of bearing wear.

Question 37

what type of gauge is used to measure the clearance between the high pressure and low pressure turbine?

Answer 37

taper gauge

Question 38

when replacing a propulsion turbine journal bearing, the rotor must be lifted vertically to what maximum height, in order to ease the removing of the lower half of the bearing ?

Answer 38

.005 inch

Question 39

if damaged labyrinth packing cannot be replaced due to operation commitments, how can the packing be repaired?

Answer 39

by use of a chisel bar and. hand chisel to straighten the teeth

Question 40

what action must be taken if you suspect internal turbine damage that warrants lifting the turbine?

Answer 40

a request to lift is made to NAVSEA

Question 41

whenever a propulsion turbine casing joint is opened for any reason, a final contact check is required by taking red and blue check of the made up joint, what is the required contact for non pumping groove joints?

Answer 41

75 percent contact over the entire joint plus 1/2 inch minimum continuous contact and inside the bolts and across each pressure section

Question 42

when is the work considered complete on a propulsion turbine that was opened for inspection and repair?

Answer 42

after satisfactory dock and post repair trials

Question 43

how many types of propulsion turbines are used in the Navy?

Answer 43

five

Question 44

on an SSTg, what is used to seal the nozzle diaphragm and the rotor to prevent steam leakage?

Answer 44

labyrinth packing

Question 45

what is the function of the staff packing on an SSTG?

Answer 45

to prevent leakage of steam from an ingress of air into the turbines

Question 46

to obtain maximum effective sealing of the labyrinth packing the rip width of packing should be maintained within what parameter?

Answer 46

.010 inch

Question 47

what NSTM contains information on the repair and care of labyrinth packing?

Answer 47

NSTM 231

Question 48

what is the most common slant that is used on turbine casing joints?

Answer 48

copalite

Question 49

what is the most common cause of turbine blade failure?

Answer 49

resonant blade vibration

Question 50

what method of measurement is used to determine radial seal wear?

Answer 50

crown thickness method

Question 51

prior to conducting thrust bearing measurements on the main engine, the turbine must be at ambient temperature with the throttles shut for what duration?

Answer 51

24 hours

Question 52

steam turbine rotos and bearings are classified as what level of repairable part?

Answer 52

depot level

Question 53

when a defective turbine part is received from the navy stock system, what report must be filed?

Answer 53

the quality deficiency report (QDR), SF 364

Question 54

what is the most commonly used propulsion turbine?

Answer 54

Type II-A (straight through unit)

Question 55

a constant security watch must be maintained when conducting turbine nozzle clearances, the watch must be who?

Answer 55

a responsible E-5 or above

Question 56

turbine lagging pads must be verified as non asbestos by using what guidance?

Answer 56

NSTM 635

Question 57

what advantage does a locked train reduction gear have over other designs?

Answer 57

has the capability of transmitting higher powers, lower sensitivity to misalignments and ease of misalignments

Question 58

main reduction gears are inspected by NAVSEA at what interval?

Answer 58

every ten years or when conditions warrant

Question 59

who is authorized to extend the ten year reduction gear inspection?

Answer 59

by TYCOM when operating conditions indicate that a longer interval between inspection is desirable

Question 60

detailed information on reduction gear security can be found in what NSTM?

Answer 60

NSTM 241

Question 61

what are two types of reduction gears used in auxiliary type ship?

Answer 61

worm and helical

Question 62

what type of reduction gear would you expect to find inane auxiliary type ship?

Answer 62

tandem articulated double reduction with one or more power inputs

Question 63

define transverse diametrical pitch of a reduction gear?

Answer 63

the ratio of the number of teeth of the number of inches of the pitch diameter

Question 64

when the ship is within 1 hour of port or anchorage and maintaining standard speed the reduction gear lube oil temperature is lowered to what?

Answer 64

10-15 degrees F or 100 degree minimum

Question 65

while import, how often must the secured reduction gear be rotated with lubrication?

Answer 65

weekly

Question 66

during the weekly lubrication of the reduction gear, the propeller shaft should be jacked how many turns?

Answer 66

one and quarter ( 1 1/4) turns

Question 67

what inspection is accomplished bi weekly on a secured reduction gears?

Answer 67

visual inspection

Question 68

inspection plates, connections, fittings or covers, which permit access to the reduction gear casing, must not be removed without whose authority?

Answer 68

engineer officer

Question 69

what NSTM has general reduction gear information?

Answer 69

NSTM 241

Question 70

reduction gears having a 125 k-factor or less must have a tooth contact of what, to be considered satisfactory?

Answer 70

80 percent

Question 71

what determines the blacklash on a pair of double helical gears?

Answer 71

longitudinal movement

Question 72

a standard SSTg reduction gear has a gear ratio of what?

Answer 72

8 to 1

Question 73

after installing new bearings on an SSTG reduction gear, what is the required gear tooth contact?

Answer 73

90 percent contact

Question 74

what is the required reduction gear tooth contact for an SSTG with helical gear?

Answer 74

80 percent of the face width

Question 75

where is the pre close out inspection of the main reduction gear logged?

Answer 75

in the engineering log

Question 76

who conducts the pre close out inspection of the main reduction gear?

Answer 76

engineer officer

Question 77

what is the requirement for the installation of locks on main reduction gear panels and plates?

Answer 77

locks are required on all apnea and plates with 1 or fewer bolts and nuts

Question 78

who performs the ten year reduction gear inspection?

Answer 78

naval shipyard or contracts shipyard

Question 79

all reduction gears are fitted with oil spray nozzles oil onto the gears, if these nozzles become clogged when corrective actions must be taken?

Answer 79

secure the gears and clean the affected oil spray nozzles. scary nozzles are required to be kept open during any gear operation

Question 80

main engine turbine bearings are measured for what at what normal interval?

Answer 80

annually

Question 81

when must a constant be re-estalished on a main engine bearing?

Answer 81

upon bearing replacement

Question 82

where are bearing measurements recorded and by whom?

Answer 82

by the work center supervisor and logged in a permanent bearing book

Question 83

define the term blacklash?

Answer 83

the amount by which the width of a tooth spaces exceed the tooth thickness of the engaging tooth at the operating pitch circle

Question 84

define the term K-factor when associated with reduction gears

Answer 84

an index that indicates the intensity of tooth from the standpoint of tooth surface durability

Question 85

what two processes are used to Harden gear elements?

Answer 85

carburizing and nitriding

Question 86

what is the most common bearing found in MRG's?

Answer 86

sleeve type

Question 87

how is a dental type coupling lubricated?

Answer 87

by a continuous flow of oil to the coupling teeth through the adjacent bearing feed line or spray nozzle

Question 88

the electric motor driven turning gear to what on the MRG?

Answer 88

1st reduction gear

Question 89

what is used to remove airborne oil fog emanating from the MRG vent airstream before it can be discharged into the machinery space?

Answer 89

the electrostatic (vent fog) precipitator

Question 90

what is located after the air inlet within the bottom of the vent fog precipitator?

Answer 90

a flame arrestor assembly

Question 91

what is the only acceptable criteria for an operating MRG lube oil sample?

Answer 91

clear and bright

Question 92

when does torsional critical speed normally occur in an operating MRG?

Answer 92

at low speed

Question 93

after securing the MRG, the main lube oil pump is secured IAW what criteria?

Answer 93

once the lube oil temperature is within 10 degrees F of engine room ambient temrpature

Question 94

when the ship is docked and the gears are rotated by the turning gear, throttles are close and secured with chain and lock. who is responsible for the key to that lock?

Answer 94

the engineer officer

Question 95

when a dehumidifier is installed during an extended MRG lay-up, the dehumidifier must maintain what relative humidity within the MRG casing?

Answer 95

less than 35 percent relative humidity

Question 96

access covers or plates installed on MRG attached with less than 12 nuts and bolts have what percentage secured with a lockable cover?

Answer 96

25 percent

Question 97

who authorizes any dismantling or removal of any MRG casing or its access openings, piping, matched fixtures, or fittings?

Answer 97

engineer officer

Question 98

custody of keys for all security locks are the responsibility of whom?

Answer 98

OEM personnel

Question 99

at what frequency is the main shaft inflatable seal tested?

Answer 99

semi-annual or IAW PMS

Question 100

what medium is used to inflate the main shaft seal under normal conditions?

Answer 100

CO2

Question 101

what NSTM covers general information on all types of propellers?

Answer 101

NSTM 245

Question 102

the area most likely to cavitate on a propeller is?

Answer 102

the suction side of the outer radii and areas near the leading edge

Question 103

a propeller that vibrate at natural frequency is characterized by what term?

Answer 103

singing

Question 104

propellers that have been in operation for more than five years must be inspected by what technique?

Answer 104

liquid penetrant

Question 105

upon completion of a propeller visual inspection report, the report is submitted to whom?

Answer 105

type commander or ship's CO

Question 106

what type of proper cleaning uses non siliceous material?

Answer 106

hone blasting

Question 107

who approves all procedures for repairing non bronze propellers?

Answer 107

NAVSEA

Question 108

waterborne propeller visual inspections are conducted at what frequency?

Answer 108

every six months