Understanding motor reliability

How MCA and ESA transform heavy industry maintenance

Electric motors are the silent workforce of heavy industry. Whether in mining, manufacturing, oil and gas, utilities or processing plants, they power pumps, conveyors, fans, compressors and countless other assets that keep operations moving.

Despite this critical role, motors are often overlooked until something goes wrong. When a failure occurs, the costs are immediate and substantial — unplanned downtime, production losses, emergency repairs and potential safety risks.

Why motors fail

Understanding why motors fail is the first step towards preventing costly breakdowns. The stresses they endure are both electrical and mechanical. Insulation breakdown can lead to winding faults, rotor bar defects reduce stability, bearings deteriorate due to misalignment or lubrication issues and unbalanced or misaligned loads cause excessive vibration. Overheating, overloading and environmental factors such as dust or moisture only accelerate these issues.

Some problems build gradually over time, while others emerge suddenly. Without reliable diagnostic methods, maintenance teams are often forced into reactive mode, responding only after a breakdown has disrupted operations. The result is wasted time, higher costs and lower reliability.

From reactive to predictive

The limitations of reactive and preventive maintenance have long been recognised. While preventive programs reduce the likelihood of failure, they often rely on fixed schedules rather than the actual condition of the equipment. Components may be replaced too early, wasting resources or too late — missing signs of imminent failure.

Predictive maintenance takes a more intelligent approach. By monitoring the health of motors with diagnostic tools, it becomes possible to detect issues at an early stage, well before they impact production. This not only prevents catastrophic failures but also allows maintenance teams to plan interventions efficiently, minimising costs and maximising uptime.

For decades, maintenance strategies have evolved in response to this problem. From reactive repairs to preventive schedules, each step has brought improvements, but the real breakthrough has come from predictive maintenance powered by advanced diagnostic technologies. Two methods in particular have proven invaluable in detecting motor faults before they become failures — Motor Circuit Analysis (MCA) and Electrical Signature Analysis (ESA).

Motor Circuit Analysis: a closer look

MCA is an off-line, or de-energised, method of assessing a motor’s winding system. Because it does not require the motor to be running, MCA is particularly effective for acceptance testing of spares, commissioning of new installations and scheduled inspections during planned shutdowns.

The method involves applying a series of low-voltage tests to evaluate the integrity of insulation, detect phase imbalances and identify weaknesses in both stators and rotors. Subtle changes in impedance, resistance and phase angle provide early warning of problems that might otherwise remain hidden until failure occurs.

In short, MCA allows maintenance teams to establish a baseline of motor condition and to track deterioration over time with confidence.

Electrical Signature Analysis: real-time insights

ESA excels in the field. As an on-line, energised testing method, ESA captures the current and voltage signals of a running motor and translates them into a detailed picture of both electrical and mechanical performance.

By analysing the motor’s electrical “signature,” ESA can reveal rotor bar defects, bearing faults, misalignment, eccentricity and even power quality issues that affect efficiency. It provides a direct view of how motors behave under load and in real operating environments, making it invaluable for troubleshooting intermittent problems and verifying whether load conditions are within design parameters.

The combined advantage

Individually, MCA and ESA provide valuable insights. Used together, they create a complete framework for motor reliability. MCA identifies underlying electrical weaknesses, while ESA demonstrates how those weaknesses play out under real-world operating conditions. This combination gives maintenance teams a holistic understanding of motor health, enabling them to move beyond guesswork and into evidence-based decision-making.

Industries that integrate both techniques into their reliability strategies consistently report tangible benefits — reduced unplanned downtime, extended motor lifespan, more efficient maintenance planning, lower operating costs and even energy savings through improved efficiency.

Industry-wide relevance

The relevance of MCA and ESA extends across the entire spectrum of heavy industry. Manufacturing plants rely on motors to keep production lines moving without costly interruptions. Oil and gas operations depend on early fault detection to maintain safety and throughput. Utilities and water treatment facilities require pumps and fans to run continuously, while processing plants and power generation sites benefit from uninterrupted performance and improved efficiency.

Wherever electric motors play a critical role, these diagnostic methods provide a competitive advantage. By shifting maintenance strategies from reactive to predictive, organisations can reduce unplanned downtime, extend the life of assets and achieve measurable gains in reliability and cost efficiency.

Closing the skills gap

Despite their proven value, MCA and ESA are still underutilised in many organisations. One reason is the skills gap. Instruments are only as effective as the people using them. Maintenance and reliability teams need more than just theoretical knowledge — they need practical training in how to conduct tests, interpret results, and apply findings to real operational challenges. Without these skills, valuable data risks being underused or misinterpreted.

This is why specialist training is so important. By equipping professionals with hands-on experience, organisations can ensure that their investment in diagnostic technology delivers measurable improvements in reliability.

About All-Test Pro

All-Test Pro is a global leader in electric motor testing technologies, known for its innovative, non-destructive testing solutions. Its instruments are trusted by maintenance professionals worldwide to improve reliability and extend motor life.

This November, apt Group, in partnership with All-Test Pro, will host the Motor Diagnostic Workshop (MDW) in Perth. This five-day, IACET-certified training event will deliver practical, hands-on learning in the latest motor testing techniques, giving participants the skills to identify and address issues before they become costly failures.

The workshop runs November 17-21 2025 at the Holiday Inn Perth City Centre, led by Bill Kruger, a recognised industry expert with more than 40 years of field experience. Mr Kruger’s extensive background in motor reliability and predictive maintenance ensures participants will gain real-world insights that can be immediately applied in their own facilities

As industries continue to push for greater efficiency and reliability, the ability to predict and prevent motor failures is becoming a defining capability. MCA and ESA represent the forefront of this shift, offering insights that empower maintenance teams to act before problems escalate.

For more details or to register, contact info@aptgroup.com.au or visit www.aptgroup.com.au