Tachometer for Factory Maintenance: How to Measure Motor and Machine RPM Malaysia
Meta Description: Learn how tachometers help Malaysian factories measure motor, fan, pump, conveyor and rotating-shaft speed for maintenance and troubleshooting.
Rotational speed affects the performance of motors, pumps, fans, conveyors, gearboxes and production machinery.
Incorrect RPM may cause reduced output, abnormal vibration, insufficient airflow, belt slippage, process instability or higher energy consumption.
A tachometer allows maintenance teams to measure rotational speed and compare the actual result with the expected operating condition.
What Is a Tachometer?
A tachometer measures the rotational speed of a moving component.
The result is commonly displayed in:
Revolutions per minute
RPM
Depending on the tachometer type and accessories, some instruments may also measure:
Surface speed
Linear speed
Total revolutions
Frequency
Always confirm the exact functions of the selected model.
Factory Applications for Tachometers
Tachometers may be used to measure:
Electric motors
Industrial fans
Pump shafts
Conveyor rollers
Pulleys
Gearbox shafts
Mixers
Centrifuges
Machine spindles
Generators
Production equipment
RPM data is useful for commissioning, routine inspection, troubleshooting and condition monitoring.
Contact vs Non-Contact Tachometers
Non-Contact Tachometer
A non-contact tachometer usually uses a laser or optical beam and reflective tape.
Advantages include:
No physical contact with the rotating component
Suitable for many accessible shafts and pulleys
Reduced risk of affecting the machine speed
Convenient for routine RPM checks
The reflective target must be visible and safely accessible.
Contact Tachometer
A contact tachometer uses an attachment that physically touches the rotating shaft or moving surface.
Depending on the accessory, it may measure:
Rotational speed
Surface speed
Linear speed
Contact measurement is only suitable when the rotating component can be approached safely.
Non-Contact vs Contact Tachometer
FeatureNon-Contact TachometerContact TachometerPhysical contactNot requiredRequiredTypical targetShaft, pulley or rotating discShaft end or moving surfaceReflective tapeUsually requiredNot requiredSuitable for enclosed componentsOnly if the target is visibleUsually notSafety distanceCan measure from a suitable distanceRequires close accessSurface-speed measurementNormally notAvailable on suitable models
1. Measuring Electric Motor Speed
Motor RPM may be checked to verify:
Expected operating speed
Variable-frequency drive setting
Motor performance
Belt-drive condition
Production-machine speed
Possible slippage
The measured RPM should be interpreted according to:
Motor design
Supply frequency
Number of poles
Mechanical load
Variable-frequency drive output
Slip
The nameplate’s synchronous or rated speed and the actual running speed may not be identical.
2. Measuring Industrial Fan Speed
Fan speed directly affects airflow and system performance.
Incorrect RPM may contribute to:
Reduced airflow
Excessive airflow
Higher noise
Increased vibration
Poor cooling
Increased power consumption
Record fan speed together with vibration, motor current and airflow measurements.
3. Measuring Pump Speed
Pump performance is related to rotational speed.
Speed changes may affect:
Flow
Pressure
Energy use
Cavitation conditions
Vibration
A pump-speed reading should be considered together with pressure, flow and motor-current information.
4. Measuring Conveyor Speed
A tachometer can check the rotational speed of:
Conveyor motor
Drive shaft
Pulley
Roller
On suitable contact tachometers, a surface-speed attachment may measure linear belt or roller speed.
Incorrect conveyor speed can affect:
Production timing
Product spacing
Filling or packaging accuracy
Process synchronisation
Material handling
5. Checking Belt Slippage
Belt slippage may cause the driven component to rotate slower than expected.
Possible signs include:
Reduced fan or pump speed
Belt noise
Belt dust
Heat
Reduced production output
Speed instability
Measure both the driving and driven components where safe and practical.
Pulley diameter and drive ratio must be considered when comparing the results.
6. Verifying Variable-Frequency Drive Output
A variable-frequency drive changes motor speed by controlling output frequency.
A tachometer provides an independent measurement of actual shaft speed.
This helps technicians compare:
Commanded speed
Displayed drive frequency
Actual motor RPM
Actual driven-equipment speed
Differences may be related to motor slip, belt drive, gearbox ratio or mechanical loading.
7. Supporting Vibration Measurements
Vibration behaviour can change with rotational speed.
When recording vibration, also record RPM because:
Similar faults may produce different vibration levels at different speeds
Resonance may occur within a particular speed range
Imbalance-related vibration depends on speed
Trend comparisons require consistent operating conditions
A vibration reading without speed information may be difficult to interpret.
How to Use a Non-Contact Tachometer
Step 1: Select a Safe Measurement Location
Choose a visible rotating surface that can be measured without removing necessary guards from operating equipment.
Step 2: Apply Reflective Tape
Apply a small piece of suitable reflective tape while the machine is fully stopped and isolated.
Step 3: Confirm One Reflective Target
Multiple reflective marks can cause the instrument to display a multiple of the actual speed.
Step 4: Start the Machine Safely
Follow the approved operating procedure.
Step 5: Aim at the Reflective Target
Maintain the distance and angle recommended by the manufacturer.
Step 6: Confirm a Stable Reading
Take several readings and check for consistency.
Step 7: Record the Result
Document the equipment, location, RPM, load, date and operating condition.
Common Non-Contact Tachometer Problems
Reading Is Unstable
Possible causes include:
Target is too small
Reflective tape is damaged
Measurement angle is incorrect
Distance is unsuitable
Shaft speed is fluctuating
Strong surrounding light
Multiple reflective surfaces
Instrument movement
Reading Is Twice the Expected Speed
There may be two reflective targets on the rotating component.
No Reading Is Displayed
Check:
Battery
Reflective tape
Target visibility
Measurement distance
Instrument mode
Rotating speed
Optical path
How to Use a Contact Tachometer Safely
Contact measurement requires physical access to a moving component.
Before use:
Confirm that contact measurement is necessary
Select the correct attachment
Check the instrument’s speed range
Ensure stable body position
Keep loose clothing and hair away
Use guards and safe access arrangements
Follow the factory’s machine-safety procedure
Never approach an unsafe rotating shaft merely to obtain a speed measurement.
Understanding Gearbox Ratios
A gearbox changes the relationship between input and output speed.
For a reduction gearbox:
Output Speed = Input Speed Ă· Gear Ratio
For example, an input speed of 1,500 RPM through a 10:1 reduction gearbox would theoretically produce approximately 150 RPM at the output.
Actual results may differ slightly because of system design, slip and operating conditions.
Understanding Pulley Ratios
For a basic belt-drive system, speed depends on the pulley diameters.
A larger driven pulley generally rotates more slowly than the smaller driving pulley.
When investigating unexpected speed:
Measure both pulley speeds
Check pulley diameter
Inspect belt condition
Check belt tension
Look for slippage
Confirm the intended drive ratio
UNI-T UT371 Tachometer
The UNI-T UT371 is a non-contact tachometer suitable for measuring rotational speed in various maintenance and industrial applications.
Potential uses include:
Motor RPM checks
Fan-speed verification
Pump-shaft measurements
Pulley-speed checks
Conveyor maintenance
Production-machine troubleshooting
Before purchasing, confirm the model’s measurement range, working distance and functions against the intended application.
Features to Consider When Buying a Tachometer
Measurement Method
Choose non-contact, contact or a combination model.
Speed Range
Ensure the range covers both low- and high-speed equipment.
Working Distance
For optical models, check the recommended target distance.
Accuracy and Resolution
Select performance appropriate for the maintenance task.
Data Hold
Data hold helps when the display cannot be read continuously during measurement.
Minimum, Maximum and Average Functions
These functions help evaluate fluctuating speed.
Memory
Stored readings can support inspection records.
Surface-Speed Measurement
Choose a contact model with appropriate accessories if linear speed is required.
Common Tachometer Measurement Mistakes
Avoid:
Applying reflective tape while the machine is moving
Using more than one reflective target
Measuring at an unsuitable angle
Standing too close to rotating equipment
Removing guards without proper isolation
Comparing speeds without considering pulley or gearbox ratio
Ignoring variable-frequency drive settings
Recording RPM without machine-load information
Using contact measurement where safe access is not available
Confusing RPM with linear surface speed
Recommended Supporting Instruments
Maintenance RequirementSupporting InstrumentMachine vibrationVibration meterMotor currentClamp meterBearing and motor temperatureThermal camera or infrared thermometerFan airflowAnemometerMachine noiseSound level meterVoltage and frequencyDigital multimeter
Tachometer Supplier in Malaysia
MTM Precision supplies tachometers for electric motors, fans, pumps, conveyors, pulleys, gearboxes and factory production machinery.
Available options include the UNI-T UT371 non-contact tachometer and other models for rotational and surface-speed measurements.
We can help customers select a suitable tachometer according to speed range, measurement distance, contact requirements and intended equipment.
Contact MTM Precision
MTM Precision Sdn. Bhd.
Showroom & Service Centre
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia
🌐 Website: www.mtmpre.com.my
📧 Email: mtmpre@yahoo.com
📱 WhatsApp: +6016-660 7346
31 Aug 2026
