Motors Hiding Weaknesses?

Today’s thermal imagers offer access to temperature measurements you might not have been able to capture before as part of your maintenance record.

A consistent maintenance program can help you avoid wasting resources on preventable equipment failures.

By Jason Axelson, Fluke Corp.

Your maintenance program supports equipment reliability throughout your facility, helping you avoid costly in-service breakdowns and empowering informed decisions. An effective maintenance program:

• Is built on documented, detailed standard maintenance procedures and intervals for all equipment. This ensures consistent data collection and supports training.

• Assembles data in an accessible CMMS (Computerized Maintenance Management System) to facilitate analysis and support troubleshooting.

• Captures staff comments with the data, which can reveal insights.

• Accounts for equipment manufacturer specifications and maintenance recommendations.

Power quality has a significant impact on equipment performance and energy efficiency.

Overlooked factors can undermine even a carefully crafted maintenance program. This is especially true with motors, which typically consume more energy than any other operating technology in a facility. These motor factors should be priorities:

Motor size: An incorrectly sized motor can not only waste energy, but time (and money) spent on maintenance, repair, and replacement. While a larger motor may be selected to “handle anything,” a motor running below its rated load has a poor power factor. This inefficient power usage pulls more reactive energy—energy that’s not doing work, but simply powering a component —from the utility, which increases your energy costs.

An undersized motor will be chronically overloaded, increasing its maintenance burden and resulting in premature failure. That motor will deliver inadequate torque for its application, so it can’t perform its own process efficiently. This could damage other equipment or cause process failure.

Power balance: Power quality matters to motors. A power-quality analyzer can track a motor’s energy consumption, current draw or load, and power factor over time, revealing any voltage unbalance. Unbalance at the electrical panel, frequently caused by putting too many loads on one phase, has a detrimental effect on motors. For about every 1% of voltage unbalance, you could observe 6% to 10% current unbalance, which creates heat and drives insulation breakdown.

Temperature: Heat is an expected byproduct of most machine processes, but it can also be an early warning. Advances in thermal-imaging technology make it possible to record temperatures that previously could not be detected. The newest units are easier to use without lengthy training; they allow technicians to read temperatures at a distance and in noisy environments, without shutting down the system. Thermal images stored in a CMMS can highlight discrepancies to investigate.

Environment: Motors typically have some type of a fan-based interior cooling mechanism with external heat-sink fins. The motor’s casing and fins must be kept clean and free of debris. Dirty or obstructed fins hamper motor cooling, which can cause heat buildup and, ultimately, insulation failure. If a motor is designed for a wet environment, it also needs good drainage.

Maintenance is your early warning system. A consistent, data-driven maintenance program helps you make informed decisions that keep your systems operating smoothly, which helps reduce unexpected downtime (and unhappy customers). It’s a body of knowledge about the workings of every machine in your facility, giving you early visibility to performance deviations and time to decide on corrective action before an issue becomes a costly emergency. EP

Jason Axelson is a Product Application Specialist with Fluke Corp., Everett, WA (fluke.com), a leading manufacturer of electrical test and measurement tools. His focus is on application awareness, product education, user training and support, and worker safety.