Picking the right motor condition monitoring system

A motor condition monitoring system is integral to sustainably maintain energy savings and extending motor life expectancy. A 100-hp motor/load consumes 795,118 kWh of energy in a year at 85% efficiency. At 95%, the same motor uses only 691,579 kWh. That’s $48,411 in annual savings at $0.07 per kWh.

By Narayanan R. March 3, 2022
Courtesy: L&T Technology Services

 

Learning Objectives

  • Review essential attributes for a motor condition monitoring system.
  • Explore condition monitoring methods for motors.
  • Learn to improve motor efficiency, realize savings, with energy-based condition monitoring systems.

Plant equipment seldom fail due to age, and most failures occur at random, without prior alerts. Manufacturers can prevent random equipment failures by monitoring the equipment and motors periodically. Conventional monitoring processes have been labor-intensive and inefficient. With the rising demand for energy-efficient motors, consistent motor health monitoring has become critical. Condition monitoring systems have emerged as a way to prevent unplanned downtimes.

The first step to implement condition-based monitoring (CBM) for plant equipment is building connectivity, which helps ensure smooth integration with OT systems in an organization. The additional software layer can help get the previous untracked data to enable historic data analysis.

Condition-monitoring systems use sensors and an asset performance management (APM) platform. The idea is to collect, sort and analyze streaming data from the sensors. The platform applies complex algorithms to these values and evaluates the equipment’s condition. The condition is assessed by comparing the current performance values to the threshold values specified by the manufacturer or industry standards. The platform also considers historical data that helps identify the non-conformities in performance. This enables operators to schedule preventive maintenance and avoid unexpected and expensive corrective actions.

A condition-monitoring system has the potential to predict failures, increase uptime and optimize operations. Extracting maximum effectiveness from a condition-monitoring system requires careful planning and deployment.

Essentials for a condition monitoring system of motors

Effective monitoring of a motor requires operators to test all its components, such as the copper winding wire, rotor, bearings, stator, insulation systems, and the electrical interconnects. Successful diagnosis of a motor’s condition requires testing in offline and online modes.

Operators can test the insulation systems in the offline mode. This involves testing for meg-ohm, surge, winding resistance, high-potential, and step-voltage.

Online testing is done for electrical and mechanical components. The condition monitoring system of motors should be able to track voltage change and identify subtle power issues that emerge from voltage imbalance, low/high voltage or harmonics. A condition monitoring system should determine the root cause of any potential failure, including those arising from misalignment, and issues from rotor bars and bearings.

To get a broader view of operation of the motor and its effect on the operation system, the motor should be integrated with upstream and downstream equipment. Motor integration adds prediction opportunity to identify faults in an ecosystem of connected machines. Mixing analytics with insights serves is an ideal way for maximizing CBM value.

Continuous condition monitoring provides operators real-time intelligence about the motor’s performance and health. Courtesy: L&T Technology Services

Continuous condition monitoring provides operators real-time intelligence about the motor’s performance and health. Courtesy: L&T Technology Services

Ideal condition monitoring system for motors

Organizations can find condition monitoring systems in the market that use different parameters for analysis, such as vibration, ultrasound, thermography and energy. For motors, energy-based condition-monitoring systems can be more beneficial than the others.

Energy-based condition-monitoring systems of motors can detect electrical stressors that cause damage due to voltage unbalance. The system measures real-time energy consumption. Real-time energy consumption measurements enable early detection of bearing issues and arcs between windings based on historical measurements.

Continuous condition monitoring provides operators real-time intelligence about the motor’s performance and health. The insights allow them to rectify problems before motors begin operating with lower efficiency or before unexpected breakdown.

Improving motor efficiency, savings, with energy-based condition monitoring systems

A motor’s operational efficiency has a major impact on the energy consumption for a manufacturer, hence to control the energy consumption, motor’s efficiency a crucial parameter to monitor. For example, a 100-hp motor/load consumes 795,118 kWh of energy in a year at 85% efficiency. At 95% the same motor uses only 691,579 kWh. At $0.07 per kWh, the manufacturer can save $48,411 if the motor works at 95% efficiency. Condition monitoring system of motors is integral to sustainably maintain energy savings and extending motor life expectancy.

Narayanan R., global head – digital manufacturing services at L&T Technology Services, a CFE Media and Technology content partner. Edited by Mark T. Hoske, content manager, Control Engineering, CFE Media, mhoske@cfemedia.com.

KEYWORDS: Energy-based motor condition monitoring systems

LEARNING OBJECTIVES

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Narayanan R.
Author Bio: Narayanan R., global head – digital manufacturing services, LTTS