Even though he is old-school, it sounds as though Rob’s maintenance group is able to keep the plant running smoothly. That would seem to indicate that they follow recommended manufacturer maintenance and lubrication schedules, and that they survey motors and equipment with vibration and thermal analyzers to watch for abnormal conditions.

But it also sounds as if his new boss is thinking about bigger-picture issues than machine uptime; he may be considering lifecycle costs and energy efficiency. Optimizing these over the long haul may require decisions about maintenance expenditures that run counter to Rob’s training and current practices.

For example, Rob may be following the old 50/50 rule for maintaining motors. It holds that failed motors should be replaced when they are less than 50 hp or the cost to rewind is more than 50% of a new unit.

But the decision is no longer that simple. Motor efficiency has increased over the years – due in large part to the Energy Policy Act of 1992 (EPAct), which went into effect in October 1997; and more recently the Energy Independence and Security Act of 2007 (EISA), effective December 2010. Each of these U.S. laws mandates minimum efficiency for new motors.

Rob’s motor maintenance policies may have been cost-conscious from the perspective of cash flow, but he should be working to retire pre-EPAct motors – replacing them with premium efficiency units.

In the short-term, it may be more expensive than rewinding, but it decreases energy consumption and will provide long-term savings – especially as the cost of energy rises.

Additional systems savings can be realized by adding adjustable speed drives to pumps, fans and compressors to control their output – rather than using valves and dampers to control flow.

For optimal efficiency, Rob could begin looking at each maintenance installation as an opportunity to achieve system savings. Each time a component needs to be repaired or replaced, he should select a solution for high efficiency after looking at the hours of operation and his utility costs. The Baldor Energy Savings Tool may be used to analyze his installation.

This process starts by considering the driven load, and choosing the most efficient pump, fan or compressor for the job. This will reduce the amount of horsepower needed to drive the load. Then he can choose the appropriate NEMA Premium efficiency motor – which is inverter compatible – to drive it. NEMA Premium specifications are set by NEMA, the trade association for electric and medical equipment manufacturers. Selection of a transformer at or above NEMA Premium efficiency will also aid in system efficiency.

Finally, Rob may want to expand the way he defines the cost of motor maintenance – and this may be what his boss is really getting at.

If you wait until a motor fails, its replacement cost is generally far longer than the six months to a year that financial managers look for. But replacing motors before they fail can reduce unscheduled downtime. Replacing them with high efficiency motors designed to withstand the specific equipment conditions that have caused past failures can increase productivity.

Adding both of these to the energy savings can dramatically shorten the payback period of a new motor, and decrease its long-term operating cost.

 John Malinowski is the Senior Product Manager for AC Motors at Baldor Electric Co. in Fort Smith, Arkansas, a member of the ABB Group. A Baldor employee since 1982, he is a senior member of IEEE and a member of its Industry Application Society. He serves on the pulp and paper industry committee, the forest products subcommittee, and the petroleum and chemical refining committee – helping to set IEEE motor standards for these industries. He is Chairman of NEMA MG1 Motor & Generator Section, and Baldor’s representative for Energy Star Partners and the International Energy Agency’s Electric Motor Systems Annex of 4E (Efficient Electrical End-Use Equipment). In addition he works with Congress on legislation and with the U.S. Department of Energy, Natural Resources Canada and other government organizations outside of North America on various regulations.

Free download of the Be$t Baldor Energy Savings Tool allows users to better understand the energy efficiency and consumption of their current motors.