Innovative Maintenance: A Concept

Innovative maintenance, in relation to electric motors, includes identifying the impact of changes to maintenance or production and side benefits found through analyses of system conditions.

By Howard W Penrose, Ph.D., CMRP, MotorDoc LLC

There’s been a constant buzz in the reliability, maintenance, and physical-asset-management community for years about how we connect with the C-suite. When the opportunity arises, we tend to get into the weeds and focus on things such as cost avoidance, availability, or the latest set of machine failures. Recently, there’s been a greater buzz surrounding the link between safety and reliability, which is solely a correlation at this point. It won’t carry real weight until a measurable relationship has been discovered.

The interconnection between physical-asset management (PAM) and all aspects of a business is relatively complex—and recognized by philosophies surrounding ISO 55000. The basics of PAM are avoidance of failure and maintenance of equipment to maintain or extend life. So, in effect, present concepts primarily focus on keeping assets in a state of functionality instead of on potential opportunities that come with knowledge and information.

For instance, in electric-motor systems, data can be derived from the energy converter, or motor, to either make improvements on an existing system or measure the immediate impact on it. The idea of innovative maintenance, in relation to electric motors, is to find measurements on the energy converter that can be used to identify the impact of changes to maintenance or production, as well as any side benefits, including those found through electrical-signature analysis on conditions throughout the motor system.

As an example, a 94%-efficient belt-to-fan 50-hp motor at 75% load operates 2,000 hr./yr. The energy consumption is [hp x (0.7457/eff)] = [50 hp x (0.7457/0.94)] = 39.7 kW at 75% load is 29.8 kW. A review of the application shows that the original belt system is over-tensioned and 91% efficient. An improvement to a 95%-efficient cogged belt system with corrected belt tension is possible for the application. The calculated load improvement would be 29.8 kW x [(100/91) – (100/95)], or 1.4 kW. After installation it was found that the improvement was actually 25.1 kW, or 4.7 kW. Where did the difference come from?  This would represent 3.3 kW of friction load on the motor and fan bearings. The bearing life of the original application is about two yr., while the improvement increases bearing life to close to 10 years. The alteration also reduces sheave wear, changes the frequency of greasing, and reduces the overall life-cycle costs of the fan application.

Using appropriate technologies to take a different look at the direct impact of a system allows one to make informed decisions and measure the effects of any changes. For electric motors, the energy and reliability impact can easily be measured and compared with original conditions, whether the change is in production, lubrication, or precision-maintenance programs. The use of innovative maintenance technologies, such as electrical-signature analysis for motors, provides condition and operational data that can be used to estimate the impact and then confirm the estimations once the changes are applied. There’s usually a direct impact on budget lines related to profitability, throughput, and other measurable values that are viewed at the C-suite. EP

Howard Penrose, Ph.D., CMRP, is founder and president of MotorDoc LLC, Lombard, IL (motordoc.com), and most recently, past chair of the Society for Reliability and Maintenance Professionals, Atlanta (smrp.org). Contact him directly at howard@motordoc.com.