Rim & Face Flashcards
What is Shaft Alignment
Shaft alignment is the positioning of the rotational centers of two or more shafts in such a way that they are co-linear when the coupled pieces of equipment are under normal operating conditions
Collinearity
The practice of lining up the shafts of two machines that are or will be coupled to each other
Misalignment
When two shaft rotational centerlines are not collinear when the machines are in operation under normal operating conditions
Parallel or Offset misalignment
When shafts are still parallel and do not line up in either the horizontal or vertical plane
Angular misalignment
at least one of the shafts is out of place causing them to be at an angle to each other in either the horizontal or vertical plane
Combination misalignment
A combination of both offset (parallel) and angular misalignment. This is the most common form of misalignment.
Rigid coupling
a fixed union between two shafts, requires accurate alignment for smooth operation
Flexible coupling
allows for minor misalignment, the most common coupling
Special purpose couplings
completely unique, some require accurate alignment and others require a set amount of misalignment
Seals
verious types: Lip, labyrinth and mechanical. misalignment stresses components and leads to premature seal failure
Vibration
Misalignment causes vibration which leads to early failure of components, also nearby equipment
Downtime
Apart from cost of parts, there is the potential for a much greater cost in production downtime
Alignment accuracies
The better the alignment, the longer the equipment lasts between overhauls, also the better the alignment the faster a machine can rotate.
Work permit
Before doing any job, get a safe work permit, very important. Test for nearby hazards. Sets conditions for safe work such as ppe, barrier tape, signage, fire extinguisher and a watchperson
Lockout
Disabling the device you’re working on so it cannot operate during repair, also removing fluids and gases from piping and lube oil systems.
Hazard assessment
before doing the job look for potential hazards and provide controls. Know escape routes and fill out HA document. Put tools where they aren’t a tripping hazard. Familiarize with pinch points and sharp edges.
Foundation
Inspect foundation on which the equipment base is mounted. Needs to be solid and have enough mass (2.5 times equipment weight) to prevent vibration being transmitted to or from machine.
Base
Equipment mount to a base plate, must be level, solid and secured (Grout)
Hardware
Inspect all hardware associated with the job. Clean tapped holes, replace washers that are dished. Dished washers can cause motor to move sideways when tightening.
Pipe strain
Piping fastened to equipment stresses the housing due to improper alignment or not supported correctly.
Soft foot
A situation where the weights distribution of a machine is not equal on all supports. Uneven base, bent feet, feet not being same length or loose material under feet. Angular or parallel.
Parallel soft foot
Baseplate and foot are parallel
Angular heel touching soft foot
the part of the foot closest to the machine is touching the baseplate
Angular toe touching soft foot
the part of the foot furthest from the machine is touching the baseplate
