TPC 303.1 Flashcards
In belt drives, force is transmitted how?
By friction, the power transmitted equals the force multiplied by the speed of the belt
What is sheave pitch diameter?
In a v-belt sheave, the pitch diameter is always less than the outside diameter of a sheave
Conventional belts are designated how?
A, B, C, D, E. A being the narrowest and E being the widest
How are group belts made?
The backing is applied during manufacturing and actually becomes part of the belt, it gives the belt uniform strength
Manufacturing include Lubrication fittings on the unit on what type of sheave?
Spring-loaded sheaves
What’s the difference between chain drive and belt drives?
Energy is not wasted and the chain drive is more efficient than a belt drive
Roller chains include the following parts…
Roller, Bushing, Pin link, Roller link
In offset roller chains the sidebars are?
Close together
What are type B sprockets?
Flat on one side, but have a slightly extended hub on the other side.
What are type C sprockets?
Have hubs extending in both sides
How do you install a chain?
Slight amount of sag on the slack side and with the driving side in tension
What is working depth in gears?
The depth to which a gear tooth extends into the open space between the teeth of a mating gear
Why helical gears over spur gears?
Because of the smooth action of motion
In what gear type is there no interference between the teeth?
Herringbone gears
What is worm axial pitch?
Distance between the screw threads
Because miter-gear boxes are usually used for changing the direction of motion, they are not often thought of as speed reducers, however…
Miter gear boxes can provide small gear ratios, usually between 1:1 and 2:1
The first and most important step you must take when you are installing a gear drive is to?
Make sure that it is aligned properly with the machine it is driving
The mechanical power rating of a gear drive tells how much power the unit can transmit under a given set of conditions, this rating depends on?
The speed and torque of the gear drive, just as in motors
The service factor depends on the?
Duty cycle
When is splash lubrication used and what are the cons?
It is commonly used In parallel-shaft gear drives, its cons are the slow speed of some units does not cause enough splashing to provide enough lubrication. In these cases pressurized systems are used
What factors are involved in selecting adjustable speed drives?
The drive is selected by the speed required, the speed range, and the power it must deliver
How do belt type adjustable speed drives work?
The output shaft rotates at its lowest speed, as the flanges of the sheave are forced closer together, the belt rises to the outer edges of the flanges. The change in position of the belt increases the speed of the output shaft
Some adjustable speed drives use?
Gear mechanisms
Pneumatic pistons
Electric motors
Adjustable speed drives belts resemble timing belts, when chain is used it is of a?
Modified leaf
In roller type adjustable speed drives the conical roller move how?
Axially to change speed
How are indicators setup when aligning using the reverse indicator method?
One dial indicator is mounted on the coupling flange of the motor and takes measurements on the pump
The other is mounted on the coupling flange of the pump and takes measurements on the motor
A problem may be that the two units need to be lowered however…
You cannot lower one or both below the support base
How does face-rim alignment work?
Both indicators are supported on one machine and take measurements from the other machine
What is the setup for long shaft alignment?
Two dial indicators on opposite coupling flanges
What are the pros of laser alignment?
It makes alignment much easier, faster, and more accurate
What are the two classes of jaw couplings?
Rigid and flexible
What coupling can be replaced without disturbing the coupling hubs?
Chain coupling
Why do shear pin couplings have breakable metal pins that connect the driving hub to the driven hub?
In case of an overload in the driven component
The limited end float coupling is made with a?
Thrust plate
What couplings simplify the process of disconnecting a driving shaft from the driven shaft?
Spacer couplings
While the clutch is disengaged the two devices are ________ of eachother.
Independent, one device can rotate while the other remains stationary.
The friction clutch has a shifting mechanism, moving the shifting arm engages?
Or disengages the friction plates
An overrunning clutch also called a one way clutch, is often used on machines where the driven equipment…
Can speed up and damage a motor by forcing it to run too fast
What clutches start and stop frequently?
Electric clutches
What are the main components of a single impeller fluid clutch?
- Impeller
- Fluid
- Clutch housing
