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newSchoolWorks.com › VoTechWorks › Manufacturing & Marine › Industrial Maintenance › Capstone Project: Integrated Industrial Maintenance System Build › Lesson 3
MFG-INDU16-08 · Lesson 3 · 60 clock hours · practice

Commissioning, Predictive Maintenance Data Collection, and Fault Diagnosis

Objective. With the system running under supervised energization, the student will collect baseline vibration, temperature, and amperage data, then diagnose and correct three seeded faults—one mechanical, one electrical, and one PLC/control—recording root cause and corrective action for each within a 3-hour timed scenario.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed engineer or certified journey-level tradesperson or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Commissioning, Predictive Maintenance Data Collection, and Fault Diagnosis

This lesson puts every skill you have built during the program to work in a single, timed, real-world scenario. You will start a multi-component industrial system, collect baseline condition-monitoring data, diagnose three seeded faults, and document everything to professional work-order standards—all within three hours.

Pre-Start Checklist: Your First Line of Defense

Before any system is energized, a disciplined pre-start checklist prevents injuries and equipment damage. Verify that all machine guards are in place and fastened. Confirm lubrication levels at gearboxes and bearing housings. Walk the area to ensure no tools, rags, or personnel are in the machine's operating envelope. Check that all control-panel doors are closed and that any previous lockout/tagout (LOTO) has been formally removed by the authorized person who applied it. Only after every item on the checklist is signed off do you request instructor authorization to energize.

PPE for this scenario: Safety glasses are required at all times on the shop floor. Wear hearing protection whenever the system is running. For any measurement on or near energized conductors—including clamping an ammeter on motor leads—wear electrical insulating gloves rated for the voltage present and use only CAT III or higher rated instruments. Never bypass LOTO to take a reading; any such act results in immediate scenario failure.

Collecting Baseline Condition-Monitoring Data

Baseline data is the reference point against which all future readings are compared. Collect it when the system is newly commissioned and running normally.

Vibration (handheld vibration meter): Place the sensor probe firmly against each bearing housing in the same orientation every time—axial, radial horizontal, and radial vertical. Record overall velocity (in/s or mm/s) and note the measurement point on the baseline form using a permanent label or paint pen on the housing. ISO and industry guidelines provide general alarm thresholds by machine class; compare your readings to the thresholds discussed in the Predictive Maintenance module.

Temperature (non-contact IR thermometer): Aim the IR thermometer at the motor frame near the drive-end bearing, the non-drive-end bearing, and each gearbox housing. Hold the instrument at the distance specified by its spot-ratio to cover only the target surface. Record ambient temperature as well, because motor and bearing temperatures are most meaningful when expressed as a rise above ambient. A sharp temperature rise at one bearing compared to others on the same shaft often signals lubrication failure or misalignment.

Amperage (clamp-on ammeter, CAT III): Clamp around one motor lead at a time—never all three simultaneously with a single-jaw clamp. Record full-load amperage on all three phases. Unbalanced phase currents can indicate winding faults or supply-voltage imbalance. Compare measured FLA to the nameplate FLA; running significantly above nameplate indicates overload or a mechanical problem adding drag.

Record every value, the time, and the machine run-time on the condition-monitoring baseline form before moving on.

Systematic Fault Diagnosis

When you return to the system and receive a symptom description, resist the urge to start swapping parts. Use a structured, five-step approach:

1. Define the symptom precisely. What does (and does not) happen? Is there an HMI message, a pilot light on or off, a sound, a smell?

2. Identify the affected circuit or subsystem. Does the symptom point to the control circuit, the power circuit, a mechanical drivetrain, or the PLC program?

3. Test from the simplest and safest point first. Use a multimeter to verify control-circuit voltage before opening the panel. Use the PLC programming laptop in monitor mode to check I/O status before assuming a field device is bad.

4. Narrow the fault to a specific component. Half-split troubleshooting—test the midpoint of the circuit, then go toward the side that shows the problem—minimizes the number of tests.

5. Correct, verify, and document. After correction, restart the system and confirm normal operation, then complete the fault diagnosis form: symptom, test performed, measurement or observation, root cause, and corrective action.

Mechanical fault example—coupling misalignment: Symptoms include elevated vibration at 1× running speed, high bearing temperature at the drive-end, and possible noise. Use a dial indicator or laser alignment tool to measure angular and parallel offset. Correct by shimming and shifting the motor per the coupling manufacturer's tolerance.

Electrical fault example—blown control-circuit fuse: The system will not start and there is no fault light because the control circuit has no power to energize the pilot light either. Use a multimeter to check voltage across the fuse; a fuse open to current flow will show supply voltage across it (full voltage drop). Replace with the correct amp-rated fuse using a fuse puller—never use pliers on an energized fuse block.

PLC/control fault example—disabled output: The PLC scan is running and the input coil for START is true, but the output coil commanding the motor starter never energizes. In the PLC monitor, observe the output rung. If the output bit is forced OFF or the rung contains a forced condition, clear the force, save, and download only after confirming with your instructor that doing so is safe.

Post-Repair Data Collection and Work Orders

After each fault is corrected and the system restarted, repeat vibration and temperature readings at the same points and orientations as baseline. Compare pre- and post-repair values on the baseline form. If any reading remains outside the normal range, write a corrective recommendation—for example, "Drive-end bearing temperature 15 °F above ambient post-repair; recommend re-check lubrication quantity and retest in 8 operating hours."

Complete a formal work order for each fault: equipment ID, date and time, symptom, parts used (with part numbers), labor hours, and recommended follow-up PM tasks. Legible, complete work orders are not a paperwork formality—they feed the maintenance database that predicts the next failure and justifies the maintenance budget.

Passing This Scenario

All three faults must be diagnosed, root-caused, corrected, and documented within three hours. Incomplete documentation is treated the same as an unresolved fault. Any unsafe act—energized work without authorization, bypassing LOTO, using an under-rated instrument—results in immediate scenario failure and a full repeat. Safety and documentation are inseparable from technical competence in industrial maintenance.

Key terms10

Baseline dataA set of vibration, temperature, and electrical readings collected when equipment is newly commissioned and running normally; used as the reference for all future condition-monitoring comparisons.
Condition monitoringThe practice of measuring physical parameters—vibration, temperature, current—at regular intervals to detect changes that indicate developing faults before failure occurs.
Overall vibration velocityA single vibration measurement, typically expressed in inches per second (in/s) or millimeters per second (mm/s), that represents the total energy of vibration across a broad frequency range at a bearing housing.
Half-split troubleshootingA systematic fault-isolation method in which the technician tests the midpoint of a circuit or system and then moves toward the faulty half, minimizing the number of tests required to locate the fault.
Forced I/O (PLC)A software override in a PLC program that holds an input or output bit in a fixed ON or OFF state regardless of real-world field device conditions; a common source of seeded or accidental control faults.
CAT III ratingAn IEC measurement category for electrical instruments indicating they are designed and tested to withstand transient overvoltages found in fixed building installations and industrial panels; required for taking measurements at motor terminals or distribution panels.
Root causeThe fundamental physical or procedural reason a fault occurred, as opposed to the symptom; identifying root cause prevents recurrence and is a required field on a professional fault diagnosis form.
Corrective actionThe specific repair or adjustment made to eliminate a fault and restore normal equipment operation, documented on the fault diagnosis form and work order.
Temperature rise above ambientThe difference between a component's surface temperature and the surrounding air temperature; used to evaluate motor and bearing health independently of seasonal or room-temperature variation.
Lockout/Tagout (LOTO)An OSHA-required energy-control procedure in which the energy source is isolated and locked in the de-energized position, and a tag is applied, before any maintenance work begins on equipment; bypassing LOTO is an immediately disqualifying safety violation.

Worked examples4

1. You clamp your ammeter on each of the three motor leads and read: Phase A = 18.4 A, Phase B = 18.1 A, Phase C = 22.7 A. The nameplate FLA is 18.5 A. Calculate the average current and the percentage deviation of Phase C from the average.
  1. Step 1 – Calculate average current: (18.4 + 18.1 + 22.7) ÷ 3 = 59.2 ÷ 3 = 19.73 A (rounded to two decimal places).
  2. Step 2 – Calculate Phase C deviation: deviation = Phase C reading − average = 22.7 − 19.73 = 2.97 A.
  3. Step 3 – Express as a percentage of average: (2.97 ÷ 19.73) × 100 = 15.1 %.
  4. Step 4 – Compare to nameplate: average 19.73 A is slightly above the 18.5 A nameplate FLA, and Phase C is 15.1 % above average—both warrant investigation for a supply-voltage imbalance or a developing winding fault before the motor overheats.
Answer: Average current = 19.73 A; Phase C is 15.1 % above average, exceeding the commonly cited 2 % phase-imbalance guideline and requiring further electrical investigation.
2. The drive-end bearing housing reads 147 °F on the IR thermometer. Ambient air temperature is 75 °F. What is the temperature rise above ambient, and how does that compare to a general alarm threshold of 60 °F rise above ambient?
  1. Step 1 – Calculate rise: 147 °F − 75 °F = 72 °F rise above ambient.
  2. Step 2 – Compare to threshold: 72 °F exceeds the 60 °F alarm threshold by 12 °F.
  3. Step 3 – Interpret: the bearing is running hotter than the alarm level, which may indicate inadequate lubrication, overloading, or misalignment; document and investigate before continuing extended operation.
Answer: Temperature rise = 72 °F, which exceeds the 60 °F alarm threshold by 12 °F; the bearing requires inspection.
3. Before replacing a suspected blown control-circuit fuse, you take a voltage reading across it with the circuit energized. You read 120 V across the fuse. Is the fuse open or good, and why?
  1. Step 1 – Recall the principle: a fuse in a series control circuit acts like a switch. If the fuse is intact (conducting), both of its terminals are at essentially the same potential, so voltage measured across it is near 0 V.
  2. Step 2 – Apply to reading: you measured 120 V across the fuse, meaning the full supply voltage is dropping across it—current is not flowing through the fuse element.
  3. Step 3 – Conclude: the fuse is open (blown). Replace it with the correct amp-rated fuse using a fuse puller, then retest.
Answer: The fuse is open (blown). A good, conducting fuse shows near 0 V across it; 120 V across the fuse means it is open and must be replaced.
4. Post-repair vibration at the drive-end bearing is 0.31 in/s overall velocity. The baseline reading taken during commissioning was 0.14 in/s. By what percentage has vibration increased, and what does this suggest?
  1. Step 1 – Calculate increase: 0.31 − 0.14 = 0.17 in/s increase.
  2. Step 2 – Express as percentage: (0.17 ÷ 0.14) × 100 = 121 % increase above baseline.
  3. Step 3 – Interpret: vibration more than doubled after the repair. If the coupling misalignment was the seeded fault, a 121 % increase over baseline post-repair suggests the alignment correction may be incomplete or a residual mechanical issue remains; recommend re-checking alignment tolerances and re-measuring after a full thermal soak at operating temperature.
Answer: Vibration increased by 0.17 in/s, a 121 % rise over baseline; alignment should be re-verified and data re-collected after the machine reaches operating temperature.

The math in this lesson2

Learners compute percent current imbalance, temperature rise above ambient and percent vibration increase.
7.RP.3S-ID.2
Brush up in the math halls at newSchoolWorks.com:
In class: Students perform a pre-start checklist (guards in place, lubrication confirmed, area clear), then start the system under instructor supervision; they collect baseline data using a handheld vibration meter on each bearing housing, a non-contact IR thermometer on motor and bearing surfaces, and a clamp-on ammeter on motor leads, recording all values on a condition-monitoring baseline form and comparing readings against alarm thresholds discussed in the Predictive Maintenance course. · Instructor or lab technician seeds three faults in the student's system while the student is out of the area (examples: a deliberately misaligned coupling, a blown control-circuit fuse, and a forced PLC output disabled in the program); the student returns, is given a symptom description (e.g., 'system will not start; no fault light'), and must use systematic troubleshooting—voltage checks, program monitor on PLC laptop, physical inspection—to locate and correct all three faults within 3 hours, documenting each on a fault diagnosis form. · After fault correction and restart, students repeat vibration and temperature data collection and compare post-repair readings to baseline, noting any values still outside normal range and writing a corrective recommendation for each; they also complete a formal work order for each fault using the shop's standard work-order template, including parts used, labor time, and recommended follow-up PM tasks.
Materials: Handheld vibration meter, non-contact IR thermometer, clamp-on ammeter (CAT III rated), condition-monitoring baseline form, fault diagnosis form, standard work-order templates, PLC programming laptop with monitoring software, multimeter, fuse puller and spare control-circuit fuses, coupling alignment tools, personal protective equipment (safety glasses, hearing protection, electrical insulating gloves for any energized-circuit measurements), NCCER Predictive Maintenance and Electrical module references, MSSC CPT Quality Practices and Maintenance Awareness reference
Check: All three faults must be correctly identified, root-caused, and corrected within the 3-hour window; each fault diagnosis form must include symptom, test performed, measurement or observation, root cause, and corrective action. Condition-monitoring forms must show pre- and post-repair data with a written interpretation. Work orders must be complete and legible. Pass standard: all three faults resolved with documented reasoning; any unsafe act (working on energized equipment without authorization, bypassing LOTO) results in immediate failure of the scenario and requires a full repeat.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

NCCER Industrial Maintenance – Safety
1. During the pre-start checklist, you notice that a lockout device and tag are still on the main disconnect. What is the correct action?
NCCER Industrial Maintenance – Preventive and Predictive Maintenance
2. When collecting vibration baseline data with a handheld meter, why is it important to place the probe in exactly the same orientation and location at each bearing housing every time?
NCCER Industrial Maintenance – Electrical
3. You measure 120 V across a control-circuit fuse in an energized 120 V control circuit. What does this reading indicate?
MSSC CPT – Maintenance Awareness
4. A motor's Phase A draws 18 A, Phase B draws 18 A, and Phase C draws 27 A. Which condition most likely explains the high Phase C current?
NCCER Industrial Maintenance – Industrial Controls
5. In the PLC program monitor, the START rung logic is TRUE but the output coil that commands the motor starter does not energize. After checking field wiring and finding it intact, what is the most logical next check?
NCCER Industrial Maintenance – Preventive and Predictive Maintenance
6. A bearing housing temperature rise above ambient is 72 °F, and the general alarm threshold for this machine class is 60 °F. What is the correct immediate action?
MSSC CPT – Safety
7. Which instrument rating is required for taking current measurements at an industrial motor's terminal box or a distribution panel?
NCCER Industrial Maintenance – Preventive and Predictive Maintenance
8. After correcting a coupling misalignment fault, post-repair vibration at the drive-end bearing measures 0.31 in/s compared to a baseline of 0.14 in/s. What should the technician do?
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