Industrial Maintenance and Condition Monitoring

Flashcards covering electrical connections, industrial software (CMMS/EAM), PLCs, condition-based maintenance, infrared thermography, vibration analysis, ultrasonic inspection, and laser shaft alignment.

What is the requirement for electrical connection tightness according to the National Electrical Code?

Connections must be tight enough to carry the maximum circuit current without overheating, arcing, or significant voltage drop.

What are the temperature limits for conductors at equipment terminations regardless of insulation rating?

They must not be hotter than either $65\,^{\circ}C$ or $75\,^{\circ}C$, depending upon current and conductor size.

What does the acronym CMMS stand for?

Computerized maintenance management system.

What is the primary function of a CMMS?

Software that helps maintenance teams record assets, schedule and track tasks, and maintain historical records of work performed.

How is Enterprise Asset Management (EAM) defined?

The optimal lifecycle management of the physical assets of an organization, covering design, construction, operations, and decommissioning.

What is a Programmable Logic Controller (PLC)?

A small industrial strength computer used to control real-world actions based on its program and real-world sensors.

Which components do PLCs replace in older electrical panels?

Thousands of relays.

What programming language is typically used in PLCs due to its similarity to wiring schematics?

Ladder logic.

What are common examples of inputs to a PLC?

Switches, sensors, bar codes, and machine operator data.

What are common examples of outputs from a PLC?

Motors, air solenoids, and indicator lights.

What is the fundamental principle of a Condition-based (CBM) maintenance strategy?

The simple principle of "if it ain't broke, don't fix it," meaning maintenance is performed only when indicators show equipment performance is deteriorating.

How does CBM improve equipment reliability compared to a planned maintenance approach?

By discovering failures before they happen and ensuring parts are not replaced before the end of their useful life.

What is one benefit of CBM over a strictly reactive maintenance approach?

It eliminates unplanned downtime, emergency parts labor costs, and major failures that lead to health/safety risks.

What is a significant challenge regarding the initial cost of CBM?

The cost to add monitoring instrumentation can be prohibitive, especially for smaller assets where it may exceed the asset's value.

Why does CBM introduce an element of randomness into maintenance operations?

Because it is based on monitoring conditions in real time, making activities reactive and unpredictable.

What is the basic definition of Infrared Thermography?

A method that detects infrared energy emitted from an object, converts it to temperature, and displays an image of temperature distribution.

According to technical terminology, what is the specific difference between a thermograph and thermography?

The equipment is called an infrared thermograph, while the method is called infrared thermography.

What are three key characteristics of infrared thermography equipment?

It captures surface temperature distribution as visible information, measures without contact, and measures in real time.

What are the common causes of excessive equipment vibration in industrial processes?

Misalignment of equipment, unbalanced rotating equipment, or loose components such as bolts.

What is the primary purpose of Vibration Analysis?

To determine how equipment responds to an applied load or external force and to determine the root cause of failure.

What is the simplest way to identify vibration problems during a survey?

Installing portable vibration sensors (probes) in multiple locations to acquire data on vibrational modes.

What is Experimental Modal Analysis (EMA)?

A type of vibration test that applies various loads to a sample while the equipment is not in service to simulate operating conditions.

When is Operational Modal Analysis (OMA) typically used?

When background noise makes vibration signals hard to distinguish and when equipment is currently in service.

Which computational tools are commonly used to solve vibration problems through simulation?

Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD).

How do Ultraprobe ultrasound instruments detect mechanical stress in machinery?

By detecting friction and focusing on a narrow band of high frequencies.

In ultrasound monitoring, what does an $8\,dB$ gain over baseline indicate?

Pre-failure or lack of lubrication.

What does a $12\,dB$ increase over baseline indicate in ultrasound bearing analysis?

The very beginning of the failure mode.

What does a $16\,dB$ gain over baseline signify in ultrasonic bearing inspection?

An advanced failure condition.

What level of gain in ultrasound monitoring warns of catastrophic failure?

A $35-50\,dB$ gain.

What are the three specific methods used for ultrasonic bearing monitoring?

Comparative, historical, and analytical.

What is the definition of shaft alignment, also known as coupling alignment?

A process to make two or more rotating shafts co-linear, or in the same straight line, both vertically and horizontally.

Why are laser beams used in shaft alignment instead of brackets?

Laser beams are not affected by gravity or bracket sag.

What is the advantage of using "live" measuring modes in laser shaft alignment?

It monitors actual shaft rotational centers during movement, accounting for both intended and unintended movements.

Besides alignment, what other conditions can some laser shaft systems correct?

Soft foot, bolt bound, or base bound conditions.

How can laser technology assist with dynamic machinery changes?

It can measure and compensate for thermal growth of machines.