Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
74 Cards in this Set
- Front
- Back
What are the LOTO steps?
|
P - Prepare to shut down the machine
S - Shut Down/off the machine I - Isolate power supply from machine A - Apply lockout device C - Control stored energy V - Verify de-energization |
|
Why are LOTO procedures used?
|
Protects the worker who is working on the equipment. Requires a test to ensure the equipment has been de-energized. ALL sources of power must be isolated, controlled and tested before beginning work.
|
|
What 2 things must be included on a tag that has been placed on a machine?
|
"DO NOT OPERATE" and installer's name
|
|
Who is authorized to remove a LOTO device?
|
ONLY the person who installed it.
|
|
Main shaft primary function and the general function of any shaft
|
Transfers mechanical/rotary power in the for of torque to the gearbox. / Generally, a shaft transfers rotary power from one location to another.
|
|
What is the function of the gearbox in a turbine and what can it NOT do?
|
To convert low speed high torque of the main shaft to high speed low torque at the output shaft. It cannot increase overall power.
|
|
What is the purpose of the clutch?
|
Allows two shafts to be disconnected while in operation
|
|
List the four methods of power tranmission
|
Thermal, Fluid, Mechanical, Electrical
|
|
Name three types of shaft-to-adjacent shaft power transmission.
|
Belt, Chain drive, Gear Drive
|
|
What is the function of the bedplate/baseplate? What procedure is necessary before mounting?
|
Provides a rigid, level surface for mounting a motor, generator, gearbox etc. Bedplate must be leveled beforehand.
|
|
What circumstances would an adjustable motor mount be used?
|
When the tension on a belt needs to be adjusted routinely.
|
|
What are accuracy and precision? How do they differ?
|
Accuracy is how close the measured value is to the true or actual value. Precision is how close the measured values are to each other.
|
|
List the parts needed to attach a motor to a bedplate
|
hex head bolt, two flat washers, one lock washer, one nut
|
|
What ensures the bolt will not slip through the bolt hole?
|
the flat washer
|
|
How do you determine the grade of a bolt?
|
Reading/interpreting the markings on the head of the bolt.
|
|
Revolutions per Second (RPS) convert to Revolutions per Minute (RPM)
|
Multiply said number by 60 or divide if going from RPM to RPS
|
|
What two things can a level determine?
|
True horizontal and True vertical
|
|
What do you do to a key after cutting it from keystock?
|
Lightly chamfer the ends of the key
|
|
How does the torque load on the shaft of an electric motor affect the amount of electric current?
|
As torque increases, current increases. As torque decreases, current decreases
|
|
Where does the key fit in a keyed shaft and how should it fit?
|
Fits into the key seat of the shaft without being forced
|
|
Convert 25 HP to Kilowatts using Pkw = Php x 0.746
|
18.65kW
|
|
What types of motor mounts are there?
|
Foot mount, c-face/flange mount (attaches directly to the face of a component), adjustable mount.
|
|
What is end float and its tolerance?
|
The amount the shaft moves along its axis. Tolerance = .001"
|
|
What is TIR? What is run out and its tolerance?
|
Total Indicator Reading. Runout is the dynamic radial eccentricity (wobble that occurs when a shaft rotates) = 1/2 the TIR. Tolerance = .002"
|
|
What is soft foot? How do you correct it? What is the tolerance?
|
Condition of a machine where it rests on three feet instead of four. Corrected by shimming the affected foot. Tolerance = .002"
|
|
What are the four types of misalignment?
|
Vertical offset, Horizontal offset, Vertical angular, Horizontal angular. VO HO VA HA
|
|
What are the eight steps of rough alignment (including pre-alignment)?
|
Level the shaft(s) of all machines, Measure and correct soft foot, Measure shaft runout, Measure the shaft end float, Measure and correct vertical offset, Measure and correct horizontal offset, Measure and corrrect vertical angularity, Measure and correct horizontal angularity.
|
|
What five precision instruments are required to perform the pre-alignment and rough alignment procedures?
|
Dial caliper, dial indicator, straight edge, feeler guage, spirit level.
|
|
What size bolt would you use for a 1" diameter hole? 3/4" hole? 1/2" hole?
|
One size below the hole: 7/8" bolt, 5/8" bolt and 7/16" bolt.
|
|
Describe the functions of a bearing
|
Reduces friction, Guides and supports a load, replacebale wear surface.
|
|
Describe the function of a coupling
|
Conects two shafts and transfers rotary power
|
|
List and describe three types of loads on bearings
|
Radial - load is at a right angle to the shaft axis, eg: a shear load
Axial - load runs along or parallel to the axis of rotation Combination - radial and axis loads combined, eg: moment loads |
|
What are two primary categories of bearings?
|
Plain (friction) bearings and Rolling element (antifriction) bearings.
|
|
List four different shaft materials and give an advantage of each
|
Cold rolled steel: inexpensive
Hardened steel: heat treated to improve strength and durability Chrome-plated steel: corrosion resistant Stainless steel: resists rusting, stronger than cold rolled steel |
|
What is a lock collar's purpose?
|
Secures the bearing to the shaft
|
|
How do you calculate mechanical efficiency (formula)?
|
Output Power/Input Power x 100
|
|
Give five precision tool handling best practices
|
Handle with care, never drop, ensure the tool is calibrated properly, clean before each use, store in its protective case when not in use.
|
|
What tool is used to take precise outer, inner and depth measurements?
|
Dial caliper
|
|
What four things can a dial indicator be ued to measure?
|
End float, run out, soft float, and gear backlash
|
|
One inch is how many millimeters?
|
25.4mm
|
|
What is a photo tachometer's primary purpose?
|
Determins the rotational shaft speed, in RPM
|
|
What five categories are shafts specified by?
|
Type of material, Nominal diameter, Diameter tolerance, Straightness, Length
|
|
Main difference between a pillow block and flanged mount bearing?
|
Pillow - shaft mounts to a horizontal or angled surface.
Flanged - Shaft orientation is perpendicualr to the mounting surface. |
|
Main purpose of the shrink disk?
|
Couples the main shaft to the hollow gearbox input shaft.
|
|
Function of the high speed coupling?
|
Coupling that ues a rubber-like insert between two hubs to absorb any slight misalignment that may be present.
|
|
How is vertical angular misalignment measured?
|
Measuring the gap between the coupling halves at the top and bottom (90 degrees and 180 degrees)
|
|
How is horizontal angular alignment measured?
|
Measuring the gap between the coupling halves at the sides (90 degrees and 270 degrees)
|
|
What are three benefits to proper shaft and coupling alignment?
|
Reduces vibration, increases efficiency, extends the life of the coupling, bearings and seals
|
|
Main function of the rotor in a wind turbine
|
Used to capture the kinetic energy of the wind and convert it to high torque rotary motion.
|
|
Mechanical Power =
|
Work/Time
|
|
The _____ of a mechanical power transmission system is _______ than the ______.
|
Output power is always less than the input power.
|
|
Two main causes of mechanical inefficiency
|
Friction and Vibration
|
|
Power (Horsepower formula)
|
Torque(lb-ft) x Speed (rpm)/5252
|
|
What is the most common prime mover for a Mechanical Power Transmission System (MPTS)?
|
an electric motor
|
|
A ______ is used to measure both the output power and the mechanical efficiency of a machine.
|
dynomometer
|
|
Torque is determined by multiplying the _____ applied by the _______ from the axis of rotation
|
force, speed
|
|
A ______ is used to measure the electric current drawn by the prime mover
|
Amperes. Measured by inductive ammeters, digital multi-meters, built-in ammeters
|
|
The purpose of a mecahnical power transmission system (mpts) is to ________ and _____ _____ _____
|
transmit and convert mechanical power
|
|
Three methods of axial power transmissions commonly used are __________________.
|
Direct Coupled, Shaft extension, clutch coupled
|
|
Two basic types of mechanical motion
|
Linear and Rotary. Linear eg - solenoid Rotay eg - drill
|
|
Rotary machanical power has what two components?
|
Torque and speed
|
|
Torque can be defined as......
|
the tendency of a force to rotate an object about its axis. Braking force can be expressed as torque.
|
|
What is the best instrument to use when measuring an inside width of a keyseat or the depth of the keyseat?
|
Caliper
|
|
What are three functions of a foundation?
|
Support compressive and shear loads, Maintain alignment between connected components, Absorbs vibration.
|
|
A foundation is typically made of _______ or _______.
|
Solid/reinforced Concrete or Steel
|
|
ISO bolt grade indentification
|
Minimum tensile strength (stress that material can withstand before necking), second numer is yield strength. If a bolt says "8.8" on its head: 8 x 100 MPa = 800 MPa (tensile) .8 x 800 MPa = 640 MPa (yield)
|
|
Shim Ratio and Shim Value
|
Lb/Le = shim ratio (base length divided by effective length)
Lb/Le x feeler guage = shim value |
|
The device most often used to measure motor speed is a __________.
|
tachometer
|
|
Rotational speed of a motor is most often measured in ____.
|
RPM
|
|
Angular speed is measured in _____ units in the International System of measurement.
|
RPS
|
|
The ____ tachometer has attachments which enable it to take direct readings
|
hand-held
|
|
The ____ tachometer determines motor shaft speed by counting the number of times a piece of reflective tape passes through the light.
|
Photo tachometer.
|
|
Torque formula
|
Multiply load (lbs) by radius (feet) ... answer is torque.
|
|
LOTO procedures.. other than PSIACV
|
Notify affected personnel
Evaluate hazards Shut down, isolate, block + lock Tagout Flag the machine Clear Area De-energize, test it! |