Important Things to Know Flashcards
What is the turbine called that has HP and LP section on separate shaft?
Cross Compound
The greatest amount of steam expansion takes place in the?
LP Stage
On a reaction turbine the largest blades are in the?
LP Reaction
Gas turbines have the highest pressure in the?
Compressor Diffuser
Emergency blowdown valves prevent?
Over Pressuring the system
what does large diameter steam blading allows for?
High Volume Of Steam
What is used to help prevent steam leakage from blade sections?
Shrouding or Shrouds
Condenser in the turbine allows steam to perform more work by reducing pressure and?
Less Back Pressure and Recycle Condensate
Time more efficient
S.A.V is closed by?
Governor
Is the overspeed trip mounted on the rotor shaft?
Yes, the bolt has the center of gravity slightly of center of the shaft.
What is the first step in starting a gas turbine?
Start button but always follow Manufactures Pre-startup Checks
The transition piece connects the inner lines of the power plant combustor to?
Combustion chambers to the turbine and it’s duct.
What do the moving blades of the turbine consist of?
Disc or Drum Wheels
Name for stationary blades?
Nozzles
For expansion on turbines sliding dovetails are used?
On rotors for holding reaction blades
Spherical bearings used on turbines to?
To compensate for sag on shaft
Carbon rings are machined because they?
Fit with very close tolerance
On a gasoline carburetor how is the amount of gas delivery controlled?
(Butterfly Valve) Throttle Valve
Propane and most carbs used a?
Spray Bar or Nozzles
Excessive crankshaft deflection will most likely cause?
Broken crank or fatigue failure
What is a micron?
Millionth of a meter
.001 mm
What does a magneto ignition system consist of?
- Magnets
- Coil (transformer)
- Spark Plug
- Generates its own power
On a 4 stage cycle engine, intake valves opens and closes once, while the crankshaft turns how many degrees?
720°
What is artificial respiration when dealing with stationary engines?
Air is forced in to the cylinder
What controls the collapse of the primary field of the coil on an electric ignition system?
Transistors
Lacing is used in what section of the turbine?
LP Section
Reaction Blades
Labyrinth seals, seal on the principal of?
Bernoulli Principle
Knife edges
You start up a piece of equipment after an overhaul you get very high vibration readings, the next step is to?
Shut it down!
If you get fluctuations readings when you first start the equipment, wait for readings to settle, this is known as?
Hunting
On electric motor, vibration readings are highest in the axial direction, the problem is most likely?
Misalignment
Drive belt vibrations amplitude is most likely the highest in-line with?
Direction of belts, because they are pulling on the sheave
When taking vibration readings on bearings, the readings should be taken on?
Acceleration and on the Horizontal, vertical, and Axial
vibration signals are also known as?
Signatures
What is the cause of too low suction lift?
blocked intake
If you are taking vibration under 600 rpm use?
Displacement
Everything is working the way it should but the input light never comes on?
Bulb burnt-out or the switch is bad
How is the suction and discharge valves operated?
by pressure differential of the pump
Where does maximum impeller wear widely with semi fluids solids?
Blade tips
Two major types of seals used in pumps?
- Static
* Dynamic
What is the advantage of wear rings in centrifugal pump?
Increase efficiency prevent recirculation
When pumping clear unconcentrated H2O (water) with constant pressure suction side of pump, the stuffing box should work well with what kind of packing?
Solid Packing
What is the major reason for using steam throttle valves on large pump?
Direct connected valves require too much force
What can be done to modify a reciprocating pump to make it provide a steady and continuous flow?
Add air chambers to outlet side.
Accumulator
What happens when discharge valve is close on a centrifugal pump?
Pump Slip
Gate valves are used as intake and discharge valves because of?
Low Pressure Loss
7:1 compression ratio, what is most likely cause of pre-ignition?
Carbon deposits glowing red cause.
What is gear mesh frequency of a single gear reduction gear box with an input speed of 3600 rpm and output speed of 1060 with 24T.pinion
1440 hz
What is cause of too low suction lift?
Blocked Intake
What precautions is to be observed when handling and installing mechanical seals?
keep fingers away from the face of the seal
any damage with the seal face
Which process is used to seal mechanical seals in an emergency?
Lapping
How do you bring coil packing down to exact size?
Roll it with a piece of pipe (or monery) and cut all at once
How do you bring coil packing down to exact size?
Roll it with a piece of pipe (or monery) and cut all at once
When installing packing rings the joints should be installed?
90° to each other
What safety precaution is observed when working on a conveyor to make sure it does not start while you are working on it?
lock and tag (test start button)
What is the function of an electrical interlock to enable system shutdown anywhere along the line?
Times the functions
What is the probable cause of gravity take-up system that slips on start-up?
Take-up weight to light
On a belt conveyor that must be started under full load, what kind of drive should be used?
fluid coupling
What chain is best used in abrasive conditions?
mill chain or H-type
On an overload conveyors with a compound vertical curve the purpose of the straight section of track is?
to gain the required amount of elevation
On a long screw type conveyor sections of screws are joined by?
coupling or dungeon shaft
A belt that has a section of it that always runs out of alignment is probably caused by?
Improper or Uneven splice
Increasing coefficient of friction on drive pulley without increasing tension, can be accomplished by?
lagging
Snub-pulley= arc of contact
Easiest way to change speed at a conveyor?
Change sheave or sprocket diameter
On a bucket elevator the length of splice should be?
equal to the width of the belt
On pneumatic dust conveyor piping the amount of wear is?
on outside radius of elbow
If the diameter of the snub pulley is too small
adjustment will not allow for proper arc of contact
Millwright measures electrical pressure with what kind of meter?
volt meter
What steps up or down voltage?
transformer
Bearings on electric motor lock bearing at what end?
drive end
Most common way to reverse direction at DC motor
reverse armature lead
Balancing of 3 blade for imbalance of 85°
SIN LAW
Who is responsible for providing MSDS
supplier
Foot valve
on a centrifugal pump
Regenerative pump
How do you know it is one?
The way its mounted and the housing
pump curve question
10.7 psi gauge pressure
alignment question
Line # 1
Which one is the Lowest pressure from first to fourth stage
fourth stage is the lowest pressure
gate valves
are used because they are low pressure drop
butterfly valve
for lowest pressure drop
pressure drop
across both blades in a reaction turbine
belt stretch
from overloading
driven gear
on picture
balancing device on what?
single suction
open closed
diaphragm pump
2 pressure limiting valves two diaphragms
rotating part
sleeve
low npsha
suction is clogged
measure clearance
tdc on compression
condenser
to increase pressure drop
to maintain straigth flow in an axial pump
diffuser vane
how to attach long screw conveyor
couplings (dungeon)
conveyor that moves cylindrical objects
hour glass
cyclone moves material apart by
centrifugal
where is the intercooler with a turbo
after the outlet of the turbo
most wear in a pipe elbow
outside radius
blade on fan
6 or 7 weight on 120 degrees
how much ounce weight do you add to balance out
1.7 ounces
Phase are the same
Static
coil on distributor
primary voltage
semi closed impeller
on other picture
idlers spaced
for belt sag
shaft sleeve used
save on shaft costs
Your employer wants you to do computer training in addition of technical training?
Contact LAC
Local Apprenticeship Committee
where to put thermo couples
each end of turbine
camshaft changes
linear motion to rotational motion
holds belts together
Friction
how does cooling tower remove heat
By Air
Excessive crankshaft deflection
Fatigue Failure or Broken shaft
Emergency blow down valves
prevent over pressuring
Brass ring in packing
lantern ring
impeller wear
blade tips
types of seals used in pumps
dynamic and static
when pumping clear uncontaminated h2o water
used solid packing
unbalanced pump
off center in a concentric housing
best chain to use in abrasive conditions?
mill chain
blow by
oil leaking into the crankcase
in an emergency
lap mechanical seal
overspeed trip on turbine
110% to 115%
measure stroke
distance from BCC- TDC
how do you measure growth
with laser, optical, etc
axial growth in a turbine is controlled with
a key
tenon
shrouds - tip of the blade?
full load to no load
speed droop
To change the operating speed (rpm) on the governor
Adjust the spring
troubleshooting question
systematic approach
ask good question
do one thing at a time
maintenance on a valve stem
tighten nut
how is shroud attached?
it’s riveted in sections over a tenon
what is the critical speed of a rotor?
Is determined by it’s natural frequency. At this speed the motor will shake violently. The machine must accelerate quickly through the critical speed to avoid this
