Best Practice Guide

Food and Beverage Growers and Processors

Introduction

Planning an Energy Program

Funding and Approval

Commissioning

On-the-Farm Energy Use

Lighting

Building Envelope

Central HVAC System

Boilers

Steam

Combined Heat and Power

Compressed Air

Refrigeration

Motors

Energy Use Basics

Proper Maintenance

Energy-Smart Investment

Demand Response

Distributed Generation

Water Use


Fetzer Vineyard

J Vineyards and Winery

Mission Foods

S. Martinelli and Company

Sara Lee

Vineyard 29


View the Glossary

Motors

Proper Maintenance

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Proper motor maintenance should be a no-brainer. Much like an automobile needs regular oil changes and tune-ups, motor systems should be routinely maintained and monitored. Not only does proper maintenance protect expensive equipment and reduce energy use, it typically gives plant managers advanced warning when equipment starts to wear and may need to be replaced, thus minimizing or avoiding costly downtime.

Some common maintenance strategies include:

Reduce load requirements. This category encompasses a wide range of strategies such as widening pipe diameters to reduce resistance, straightening ducts, leveling process flows over time to reduce peak loads, and eliminating unnecessary by-passes. These strategies reduce and/or level loads on motors, which open up opportunities for use of smaller or fewer motors in the system. Case studies of these kinds of projects report reductions of 5 percent to 60 percent of system energy use.

Match size to load. Motor systems are often sized to accommodate expected peak load, with little or no allowance for the operation of the process at partial load. However, oversized motors lose efficiency markedly below 40 percent of rated load. Strategies to serve partial loads while saving energy include staging of equipment, automatic shutdown, parallel systems and downsizing. Estimated savings from these kinds of projects range from 5 up to 30 percent.

Adjust the impeller in pumps. As a general rule, consider adjusting the impeller in pumps with 55 to 66 percent efficiency. If efficiency falls between 50 to 55 percent, adjust the impeller first, but be ready to replace the pump if this has no effect. Pumps that fall below 50 percent efficiency should probably be replaced.

Keep motors cool. Protect motor from high ambient temperatures and minimize temperature rise of the motor system. Just like an engine in an automobile, running a motor beyond the system's capacity to cool itself causes temperature rise, which can shorten motor life and hamper motor performance. Overloading the motor, improper supply voltage (high/low), frequent start/stops, poor input power quality, restricting the cooling system and using variable frequency drives increase temperature rise.

Keep motors clean. Excessive dust and moisture cause premature wear.

Keep motors lubricated. Lubricate all moving parts on process equipment as well as motor bearings to minimize friction, improve efficiency and extend the useful life of equipment. Bearing failures are the most frequent mechanical cause of motor failure.


Resources

See Flex Your Power product guide on motors.

The National Electric Manufacturers Association (NEMA) website contains information on the NEMA PremiumĀ® energy efficiency motors program, including product specifications and a list of participating partners.

The Consortium for Energy Efficiency (CEE) website on Motors and Motor Systems includes a Motor System Tool Kit, efficiency specifications, resource links and information on the Motor Decisions Matter campaign.

Efficient Motors: Selection and Application Considerations. A brochure developed by CEE and the U.S. Department of Energy's Motor Challenge Program. Boston, MA: 1999.

U.S. Department of Energy (DOE) free software MotorMaster+ is an energy-efficient motor selection and management tool, including a catalog of over 20,000 AC motors. This tool features motor inventory management tools, maintenance log tracking, efficiency analysis, savings evaluation, energy accounting, and environmental reporting capabilities.

U.S. DOE free softwarePumping System Assessment Tool (PSAT) helps industrial users assess the efficiency of pumping system operations. PSAT uses achievable pump performance data from Hydraulic Institute standards and motor performance data from the MotorMaster+ database to calculate potential energy and associated cost savings.

Electrical Apparatus Service Association (EASA), Inc. is an international trade organization of over 2,150 electromechanical sales and service firms in 50 countries. The EASA website contains downloadable, in-depth guidelines to improve motor efficiency, repair worn or malfunctioning motors, and to help owners decide whether to replace or repair motor systems.