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BLD-WIND70-02 · Lesson 12 · 34.5 clock hours · practice

Integrated Mechanical Maintenance Practical: Drivetrain Inspection and Documentation

Objective. Students independently plan, safely isolate, inspect, service, and document a multi-system mechanical maintenance task on the drivetrain lab trainer, producing a complete work package.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed professional engineer or master 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.

Integrated Mechanical Maintenance Practical: Drivetrain Inspection and Documentation

A wind turbine technician rarely performs a single isolated task. On an actual work order you may be asked to inspect the main bearing, check gearbox oil, measure brake pads, and log pitch-bearing lubrication—all in one site visit. This lesson brings those skills together into a complete maintenance event: plan, isolate, inspect, service, document.

Why a Complete Work Package Matters

Every maintenance event generates a paper trail that follows the turbine for its entire service life. Operations teams, insurance auditors, and OEM warranty reviewers all rely on accurate records. A missing measurement or an unsigned LOTO form can void a warranty claim or trigger a regulatory finding. Your work package is your professional signature; treat it with the same care you give the equipment itself.

Step 1 — Pre-Task Planning and LOTO Procedure

Before you touch any component, write your lockout/tagout (LOTO) procedure. For a drivetrain task it must cover at minimum three isolation points:

Write each step in sequence: identify the energy source, describe the isolation action, identify the lock/tag hardware you will apply, and state how you will verify zero energy (try-out test or pressure gauge reading at zero). Have the procedure reviewed before you begin. On the lab trainer, your instructor verifies each lockout point before you may proceed—this mirrors the buddy-verification practice required on real sites.

Remember: any LOTO omission is an automatic incomplete on your work package. There are no partial-credit exceptions for safety failures.

Step 2 — Performing the Maintenance Tasks

Main-bearing visual inspection and grease application. Inspect the bearing housing for cracks, corrosion, and grease leakage. Check seal condition. Apply fresh grease with the grease gun in the quantity and grade specified on your work order. Record the grease type, quantity applied (in grams or ounces as the form requires), and any visual findings—even "no defects found" is a required entry.

Gearbox oil-level check and filter inspection. Read the oil level from the sight glass or dipstick at the specified operating or static condition noted on the work order. Record the reading against the acceptable range on the form. Inspect the filter indicator (if present) and note whether the filter is within its service interval. If the filter is due, flag it as a recommended follow-up action—you may not swap it without a separate work order authorizing that task.

Brake-pad measurement. Use calipers or a dedicated pad-wear gauge to measure pad thickness on both the drive and non-drive sides. Record both measurements in millimeters. Compare to the minimum thickness listed on the work order or OEM reference sheet. If either pad is at or below minimum, note it as a required corrective action.

Pitch-bearing grease log entry. Verify the lubrication interval, apply grease per the specified amount and grade, and complete the lubrication log with date, grease grade, quantity, technician name, and next-service date.

Step 3 — Photograph Log

Photographs are objective evidence. Capture at least six images: each LOTO device in place, the sight-glass reading before service, the brake-pad gauge in position, the grease fitting during application, and any condition of note (staining, wear, damage). Label each photo with a brief caption and the task step it documents. On a real job site, photos protect both the technician and the employer if findings are disputed later.

Step 4 — Maintenance Summary

Your one-page typed summary is a professional document, not a lab report. Use plain, direct language. State what was done, what was found, what was within limits, and what requires follow-up. Quantify everything: do not write "oil level was okay"—write "oil level read at the lower sight-glass mark; within acceptable range per work order." List every recommended follow-up action with the reason. Sign and date the summary.

Safety Points for This Practical

Rubric at a Glance

| Section | Requirement | Weight |

|---|---|---|

| LOTO procedure | Complete and correctly executed | Pass/fail gate |

| Measurement forms | All values recorded with units | Scored |

| Photograph log | Six or more labeled photos | Scored |

| Maintenance summary | Clear, quantified, signed | Scored |

Overall score of 80% or higher is required to pass. A LOTO omission overrides all other scores and results in an automatic incomplete.

Key terms8

Work packageThe complete set of documents produced for a maintenance event, including the LOTO procedure, inspection forms, photograph log, and written summary.
Lockout/Tagout (LOTO)A written procedure and physical process that isolates hazardous energy sources—electrical, hydraulic, mechanical—and prevents accidental re-energization while work is performed.
Zero-energy verificationThe try-out or test step in a LOTO procedure that confirms all energy has been released or blocked before work begins, such as pressing the start button or reading a gauge at zero.
Sight glassA transparent window or tube on a gearbox or reservoir that shows the fluid level visually without opening the system.
Pad wear limitThe minimum acceptable brake-pad thickness specified by the OEM; pads at or below this measurement must be replaced before the turbine returns to service.
Lubrication logA maintenance record that documents each greasing or oiling event, including date, lubricant grade, quantity applied, technician name, and next scheduled service date.
Hydraulic accumulatorA pressure vessel that stores hydraulic energy in the pitch system; it must be depressurized and locked out before any pitch-circuit work begins.
OEM work orderAn Original Equipment Manufacturer's written task authorization that specifies the scope, sequence, torques, lubricant specifications, and measurement limits for a maintenance procedure.

Worked examples4

1. The acceptable gearbox oil level range is between the lower and upper sight-glass marks, which represent 18 liters and 22 liters respectively. The technician reads the sight glass and estimates the level is one-quarter of the way between the lower and upper marks. What is the approximate oil volume, and is it within the acceptable range?
  1. Find the total range: 22 L − 18 L = 4 L.
  2. One-quarter of the range: 4 L × 0.25 = 1 L above the lower mark.
  3. Add to the lower mark value: 18 L + 1 L = 19 L.
  4. Compare to the acceptable range: 19 L is between 18 L and 22 L.
Answer: Approximate oil volume is 19 liters, which is within the acceptable range. Record '19 L — within limits' on the inspection form.
2. The OEM specifies a minimum brake-pad thickness of 8 mm. A technician measures the drive-side pad at 9.2 mm and the non-drive-side pad at 7.6 mm. What should the technician record, and what action is required?
  1. Compare drive-side reading to minimum: 9.2 mm > 8 mm — within limits.
  2. Compare non-drive-side reading to minimum: 7.6 mm < 8 mm — below minimum.
  3. Record both measurements on the inspection form with units: drive side 9.2 mm (OK), non-drive side 7.6 mm (below minimum).
  4. Flag non-drive-side pad replacement as a required corrective action in the maintenance summary.
Answer: Drive-side pad is acceptable at 9.2 mm. Non-drive-side pad at 7.6 mm is below the 8 mm minimum and must be replaced before the turbine returns to service. Document both values and the corrective action on the form.
3. A pitch-bearing greasing interval requires 30 grams of grease per fitting, and there are 3 fittings on the bearing. The technician's grease gun delivers approximately 1.5 grams per stroke. How many total strokes are needed to complete the lubrication?
  1. Calculate total grease required: 30 g × 3 fittings = 90 g.
  2. Calculate strokes needed: 90 g ÷ 1.5 g per stroke = 60 strokes total.
  3. Distribute evenly: 60 strokes ÷ 3 fittings = 20 strokes per fitting.
  4. Record 90 g applied across 3 fittings (20 strokes each) on the lubrication log.
Answer: 60 total strokes are required — 20 strokes per fitting — to deliver the specified 30 grams to each of the 3 pitch-bearing fittings.
4. A technician's LOTO procedure lists 5 required isolation steps. After completing the isolation, the instructor's verification checklist finds that 1 step was skipped. What is the completion percentage, and what is the rubric outcome?
  1. Steps completed correctly: 5 − 1 = 4.
  2. Percentage complete: (4 ÷ 5) × 100 = 80%.
  3. Check rubric rule: LOTO is a pass/fail gate; any omission results in an automatic incomplete regardless of percentage.
  4. The 80% completion rate does not override the gate — the work package receives an automatic incomplete.
Answer: 80% of LOTO steps were completed, but because any LOTO omission triggers an automatic incomplete per the rubric, the work package does not pass. The student must redo the LOTO procedure correctly before proceeding.

The math in this lesson1

Learners interpolate a sight-glass reading to estimate 19 L of gearbox oil within an 18–22 L range.
N-Q.3
Brush up in the math halls at newSchoolWorks.com:
In class: Each student writes a pre-task LOTO procedure covering main shaft, pitch hydraulics, and mechanical brake, then executes the isolation on the lab trainer with instructor observing—instructor verifies each lockout point before the student may proceed. · Working from an assigned mock OEM work order, the student performs a sequence of maintenance tasks over multiple sessions: main-bearing visual inspection and grease application, gearbox oil-level check and filter inspection, brake-pad measurement, and pitch-bearing grease log entry—recording all measurements and findings on official maintenance forms. · Student produces a complete work package including: completed LOTO procedure, all inspection and lubrication forms, a photograph log of at least six key conditions or task steps, and a typed one-page maintenance summary with findings and recommended follow-up actions.
Materials: Drivetrain lab trainer, all inspection/service tools from prior labs, LOTO tags and locks, grease gun, oil-level dipstick or sight glass, maintenance form set, camera or phone, word processor or pen and lined paper
Check: Work package evaluated against a multi-criteria rubric: LOTO procedure complete and correctly executed (pass/fail gate), all measurement values recorded with units, photograph log complete, maintenance summary clearly written—overall rubric score of 80% required to pass; any LOTO omission results in automatic incomplete.

Practice check8

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

OSHA 10 — Hazardous Energy Control
1. A LOTO procedure for a drivetrain inspection task must include which three isolation points as a minimum?
OSHA 10 — Hazardous Energy Control
2. During a LOTO procedure, the zero-energy verification step requires the technician to:
NCCER Wind Turbine Tech — Mechanical Systems
3. A technician measures a brake pad at 7.1 mm. The OEM minimum thickness is 8 mm. What is the correct action?
NCCER Wind Turbine Tech — Maintenance Documentation
4. When completing a gearbox oil-level check, the technician should record:
NCCER Wind Turbine Tech — Maintenance Documentation
5. The primary reason a photograph log is included in a maintenance work package is to:
GWO Basic Safety Training — Hydraulic Safety
6. While working on the pitch system, a technician notices a hydraulic fitting appears wet. The correct action before loosening the fitting is to:
OSHA 10 — Hazardous Energy Control
7. A student's work package scores 85% on the rubric but is found to have one LOTO step missing from the procedure. What is the correct rubric outcome?
NCCER Wind Turbine Tech — Maintenance Documentation
8. When writing the one-page maintenance summary, a technician should describe an oil-level finding as:
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