Chapter 20 - Preventative Maintenance Flashcards

Question

Describe the operating principles of “moving coil” and “piezoelectric” velocity transducers

Answer 1

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responding to breakdowns as they occur with servicing, adjustments, and minor repairs
or it may be and elaborate program designed to prevent breakdown or to detect minor problems that, untreated, can lead to breakdown

Answer 2

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Answer 3

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sometimes sudden failures result in injury or fatalities
replacement parts and overworked maintenance workers may not be readily available
special tools are sometimes difficult to arrange for or keep on hand
overtime cost to get equipment up and running can become exorbitant
large amounts of expensive spare parts or even entire spare machines have to be kept on hand, adding to the cost
erratic and sporadic minor breakdowns can be disruptive to efficient production

Answer 4

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- advantages
replacement of worn components usually lessens the frequency and severity of critical breakdowns
detailed inspection can be used to reveal even the most detailed problems - through inspection and NDT
problems can be analyzed further to determine their cause and prevent or eliminate them.
-disadvantages
time between inspections could be difficult to determine, resulting in over inspection which is time consuming and expensive
parts may be replaced too soon (over-maintenance)
occasionally, machinery is damaged or degraded by too frequent disassembly
some machinery problems are not evident unless the machine is running. These may be overlooked

Answer 5

A

problems can be detected in the very early stages, without interrupting the operation of the machinery
production shutdown for adjustments, more thorough investigation and repairs can be scheduled for the most opportune time
labour, tools, and spare parts can be prepared far in advance
extensive damage can be averted or minimized
repairs can be reduced
inspection time can be shortened
inspection for quality standards and help in the development and testing of new equipment

Answer 6

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takes action to correct conditions that could lead to machine degradation
identifies and corrects root causes of failures
factory personnel monitor equipment constantly to ensure normal operation – “condition based monitoring”

Answer 7

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Answer 8

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primitive - maintenance has little to no equipment documentation
elaborate - recorded and reviewed equipment records showing work history and equipment repairs

Answer 9

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manufacturer’s name
serial, model, inventory number
specifications for: horsepower, speed, wattage, amperage, voltage, speed ratio, pressure, flow capacity, etc.
in addition, blueprints, parts lists, stock numbers, suppliers’ names and information about availability may be included
operating requirements may include temperature limitations, maximum pressures and flows, allowable wear limits, normal service life or production capacity

Answer 10

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the dates, times, nature, and extent of repairs to machinery are all useful information, that help in the analysis of problems
a record of spare parts and materials used to make repairs, hours of work by maintenance personnel, and any special tools or equipment used can all help to determine type and frequency of problems likely to occur
minor repairs recorded, eventually modifications and design changes can be made to permanently rectify machine weaknesses

Answer 11

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Answer 12

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high priority numbers are assigned to equipment that is so critical that it can shut down the whole plant
next level priority is assigned to machinery relied on to keep whole departments running. Also assigned to those that are critical to product quality
decreasing priorities are assigned, down to auxiliary equipment and even random clean-up and decoration

Answer 13

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Answer 14

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Answer 15

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Answer 16

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Answer 17

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Answer 18

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1 Hz = 1 cps = 60 cpm
(cpm = Hz x 60)

Answer 19

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displacement – the distance of a vibrating object from its original rest position
amplitude – the distance from one extreme to another (when the displacement is at its maximum)

(66 cards)