How many questions are on the Red Seal Millwright exam?

The Red Seal Industrial Mechanic (Millwright) exam consists of 135 multiple-choice questions with a 4-hour time limit.

What is the passing score for the Red Seal Millwright exam?

You need a minimum score of 70% to pass, which means answering at least 95 out of 135 questions correctly.

What topics are covered on the Red Seal Millwright exam?

The exam covers 6 Major Work Activities (MWAs): Occupational Skills & Safety (25q), Rigging/Hoisting (17q), Mechanical Power Transmission (32q), Material Handling Systems (24q), Fluid Power/Hydraulics (21q), and Preventive Maintenance (16q).

Is the Red Seal Millwright exam the same across all provinces?

Yes. The exam is based on the Red Seal Occupational Standard (RSOS) and is standardized across all participating provinces and territories in Canada.

Are calculators allowed on the Red Seal Millwright exam?

Personal calculators are not permitted. A calculator is provided by the exam centre. You will not be allowed to bring your own.

Is power transmission heavily tested on the Red Seal Millwright exam?

Yes — MWA C (Mechanical Power Transmission) is the largest single section on the Red Seal exam with 32 questions out of 135. Expect pulley and gear ratio calculations, coupling selection, shaft alignment methods, and belt/chain inspection questions.

What is the formula for calculating pulley speed ratio?

Use the formula: D₁ × RPM₁ = D₂ × RPM₂. Example: drive pulley is 150 mm at 1200 RPM, driven pulley is 300 mm — driven speed = (150 × 1200) ÷ 300 = 600 RPM. Key rule: a larger pulley always rotates slower; a smaller pulley always rotates faster.

What is the difference between a positive drive and a non-positive drive?

A positive drive (chain, gear, synchronous/timing belt) cannot slip — the speed ratio is mechanically fixed regardless of load. A non-positive drive (V-belt, flat belt) relies on friction and will slip under overload. On the exam, if precision speed ratio is required, a positive drive is the correct choice.

When should V-belts be replaced on industrial machinery?

Replace V-belts when you observe cracking, fraying, glazing, or when the belt has stretched beyond the tensioner's adjustment range. Critical rule: always replace all belts in a multi-belt drive simultaneously — mixing new and old belts causes uneven loading and rapid wear of the new belts.

What are the two types of shaft misalignment and how do you correct them?

The two types are: (1) Angular misalignment — shaft centerlines meet at an angle, corrected by shimming the motor feet; (2) Parallel (offset) misalignment — shafts are parallel but offset, corrected by moving the motor laterally. Most installations have both types simultaneously.

Red Seal Exam Preparation

Millwright Power
Transmission Guide

Power transmission covers how mechanical energy moves from a prime mover to a load. This guide covers belt drives, gears, chains, couplings, ratio calculations, and maintenance principles for the Red Seal Millwright exam.

What Is Power Transmission?

Power transmission systems transfer mechanical energy from a power source (motor, engine) to a driven machine. Millwrights install, align, maintain, and troubleshoot these systems daily.

Main transmission methods:

Belt drives

Chain drives

Gear drives

Couplings

Shaft drives

Friction drives

Belt Drive Types

V-Belt Drives

Common in industrial machineryAbsorbs shock loadsQuiet operationRequires periodic tension adjustmentMultiple belts can run side by side

Flat Belt Drives

Used in older machinery and conveyorsEfficient over long distancesAllows crossed-belt configurationsSensitive to misalignment

Synchronous (Timing) Belt Drives

Positive drive — no slippagePrecise speed ratiosUsed in conveyors and roboticsRequires accurate alignment

Chain Drives

Positive drive — no slippageHigh load capacityRequires lubricationUsed in heavy-duty industrial applications

Pulley Speed Ratio Formula

Pulley Speed Ratio

Larger pulley = slower speed

Larger driven pulley → lower speed. Smaller driven pulley → higher speed.

Key Formula

D₁ × RPM₁ = D₂ × RPM₂

D₁ = Drive pulley diameter

RPM₁ = Drive pulley speed

D₂ = Driven pulley diameter

RPM₂ = Driven pulley speed

Worked Example

Drive pulley: 150 mm diameter at 1200 RPM. Driven pulley: 300 mm diameter.

RPM₂ = (150 × 1200) ÷ 300 = 600 RPM

Larger pulley = slower speed. Smaller pulley = faster speed.

Can you solve pulley ratio problems under exam time?

Practice timed Red Seal–style calculations with instant feedback.

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Belt Tension & Maintenance

Too Loose

Belt slips, reduces power transmission, causes overheating and glazing.

Too Tight

Overloads shaft bearings, causes premature belt and bearing wear.

Maintenance checks:

Check belt tension with a tension gauge or deflection method

Inspect for cracking, fraying, or glazing

Verify sheave alignment using a straightedge

Check sheave grooves for wear

Never use belt dressing on V-belts — it causes glazing and degrades the belt material

Gear Types

Spur Gears

Straight teeth parallel to shaft axis. Simple, efficient, but noisy at high speeds.

Helical Gears

Angled teeth for smoother, quieter operation than spur gears. Can transmit higher loads.

Bevel Gears

Transmit power between intersecting shafts, typically at 90°.

Worm Gears

Large speed reduction in a single stage. Self-locking in many configurations. Lower efficiency.

Rack and Pinion

Convert rotational motion to linear motion. Used in positioning systems.

Gear Ratio Calculations

Gear Ratio (3:1 Reduction)

More teeth = slower speed

Fewer teeth on driven gear = speed increase. More teeth = speed reduction.

Key Formula

Ratio = Driven Teeth ÷ Drive Teeth

Ratio > 1 = Speed reduction, torque increase

Ratio < 1 = Speed increase, torque decrease

Worked Example

Drive gear: 15 teeth at 900 RPM. Driven gear: 45 teeth.

Ratio = 45 ÷ 15 = 3:1

Driven gear speed = 900 ÷ 3 = 300 RPM

Coupling Types

Coupling Types Comparison

Tap to compare flexibility and applications

Jaw (Flexible) Coupling

Two hubs with interlocking jaws and a rubber spider insert. Common flexible coupling.

Flexibility

Moderate

Used For

Pumps, compressors, conveyors

Rigid Coupling

Precisely aligned shafts

Joins two shafts with no flexibility. Requires near-perfect alignment.

Flexible Coupling

Most industrial machinery

Accommodates minor misalignment and absorbs vibration and shock.

Jaw Coupling

Pumps, compressors, conveyors

Two hubs with interlocking jaws and a rubber spider insert. Common flexible coupling.

Grid Coupling

Heavy industrial drives

Uses a metal grid element between two hubs. High torque capacity.

Gear Coupling

High-torque applications

Uses meshing gear teeth to transmit high torque while allowing misalignment.

Fluid Coupling

Conveyors, crushers

Uses hydraulic fluid to transmit power. Provides smooth start-up and overload protection.

Shaft Alignment Basics

Shaft Misalignment Types

Angular vs. parallel offset

Always check both angular and parallel alignment when installing couplings.

Proper shaft alignment is critical for all power transmission systems. Misalignment causes increased vibration, bearing wear, coupling wear, seal failure, and reduced equipment life.

Angular Misalignment

Shaft centerlines meet at an angle. Creates cyclic loading on bearings.

Parallel (Offset) Misalignment

Shaft centerlines are parallel but not collinear. Causes vibration and coupling wear.

Common alignment methods:

Dial indicator (rim and face method)

Reverse dial indicator method

Laser alignment (most precise)

Straightedge and feeler gauges (for initial rough alignment)

Chain Drive Maintenance

Chain drives provide a positive (non-slip) drive with high load capacity, but require regular lubrication and tension adjustment.

Lubricate regularly — dry chains wear rapidly

Check chain sag — typically 2–3% of span length is acceptable

Inspect for tight links, wear, and elongation

Replace chain when elongated more than 3% (standard roller chain limit)

Align sprockets using a straightedge across the face

Replace chain and sprockets together to prevent premature wear

Sample Practice Questions

A drive pulley has a diameter of 200 mm and rotates at 1800 RPM. The driven pulley has a diameter of 400 mm. What is the speed of the driven pulley?

A drive gear has 20 teeth and meshes with a driven gear that has 60 teeth. What is the gear ratio?

What is the most common cause of V-belt failure?

Which type of coupling requires the most precise shaft alignment?

What is the purpose of a sheave in a belt drive system?

Frequently Asked Questions

Key Takeaways

When studying power transmission, focus on:

Belt drive types and selection

Pulley/sheave ratio calculations

Gear types and applications

Gear ratio calculations

Coupling types and alignment requirements

Belt tension and maintenance

Chain drive lubrication

Failure signs and troubleshooting

Continue Your Red Seal Preparation

Power transmission is just one area of the Millwright trade. Continue building your knowledge with guides on hydraulics, bearings, rigging, alignment, and safety.

Start Free Practice Start a Full Mock Exam

Continue studying:

Hydraulics Guide Bearing Installation Rigging Guide

Last updated: August 2026 · MW Red Seal Millwright Prep is built by a millwright, for millwrights. Content is aligned with the National Occupational Analysis (NOA) for Industrial Mechanic (Millwright) — the same document that structures the Red Seal exam.

Millwright PowerTransmission Guide