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Maintenance and Diagnosis of BLDC Motor Installations*

The BLDC (Brushless DC) motors are renowned for their reliability and longevity, but like any electromechanical system, they require regular maintenance and diagnostic monitoring to ensure optimal performance. This article presents best practices for keeping one or more BLDC motors in perfect condition, whether they are equipped with gearboxes or not.

1. Preventive Maintenance

Preventive maintenance aims to detect problems before they cause serious damage. It is based on several key points:

a. Checking connectors and cables

  • Inspect the connectors to prevent oxidation or loosening.

  • Check the cables for any cuts, abrasions, or signs of overheating.

  • Ensure that the cable path is protected and that no mechanical movement is likely to damage them.

b. Mechanical tightening

  • Check all bolts and fastenings, including those of the motor and, if applicable, the gearbox.

  • Insufficient tightening can cause vibrations, noise, and premature wear.

c. Cleanliness and environment

  • Keep the motor and gearbox clean, free from dust, mud, or oil residues.

  • The presence of foreign bodies can cause local overheating or blockages.

d. Monitoring noise and vibrations

  • Listen carefully to the motor in operation:

    • Abnormal noises (squeaking, clattering) may indicate a mechanical problem or worn bearing.

    • Excessive vibrations are often related to misalignment or imbalance of the rotor.

e. Thermal control and mechanical play

  • Monitor the temperature of the motor and gearbox to prevent overheating.

  • Check the axial and radial play of the rotor to detect worn bearings or faulty assembly.

2. Electronic Diagnosis

Electronic diagnosis allows for the quick identification of malfunctions via the controller and measurement tools.

a. Using the controller

  • Consult the fault codes generated by the controller: overcurrent, undervoltage, overheating.

  • Check parameters such as temperature, current, and speed to detect abnormal operation.

  • Advanced controllers also allow for data recording for later analysis.

b. Electrical measurements

  • A multimeter can be used to check phase continuity and the presence of correct voltages.

  • A clamp meter can be used to monitor the current consumed during operation and detect overloads.

c. Sensor testing

  • Hall sensors and encoders are essential for motor synchronisation.

  • If the motor loses synchronisation or exhibits irregular vibrations, it is advisable to test these sensors individually:

    • Check the output of each Hall sensor or encoder with an oscilloscope or compatible controller.

    • Replace faulty sensors to restore normal operation.

3. Specifics with Gearbox

When the BLDC motor is equipped with a gearbox:

  • Check the oil or grease according to the type of gearbox (periodic or lifetime lubrication).

  • Check the wear of gears and pinions to avoid torque loss or abnormal noises.

  • Ensure that the motor-gearbox alignment is correct to avoid mechanical stress.

4. Frequency and Methodology

  • Quick visual inspection: weekly or monthly depending on use.

  • Full diagnostic: quarterly or semi-annually, especially for critical installations.

  • Keep a maintenance log to track anomalies and interventions.

Conclusion

Regular maintenance and diagnosis of BLDC motors are essential to maximise their longevity, ensure safety, and maintain performance. Whether equipped with gearboxes or not, these motors particularly benefit from a combination of:

  • Mechanical monitoring: connectors, cables, tightening, noise, vibrations.

  • Electronic diagnosis: controller, current, temperature, Hall sensors/encoder.

A proactive approach allows for anticipating failures, avoiding unexpected downtimes, and ensuring maximum efficiency, particularly in agricultural, industrial, or robotic applications where reliability is critical.


*: The technical information presented in this article is provided for guidance only. It does not replace the official manuals of manufacturers. Before any installation, handling, or use, please consult the product documentation and adhere to safety instructions. Torque.works cannot be held responsible for inappropriate use or incorrect interpretation of the information provided.