Manufacturers Best Practice Guide

Motors: Tips for Energy Savings

Actions to improve motor efficiency:

  • Do a performance assessment and benchmark your motor systems
  • Build motor management into the overall energy management strategy, coordinating with the efficiency measures taken in other systems
  • Determine that motor output meets the specified load range. 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 50% of rated load. Strategies to serve partial loads while saving energy include staging of equipment, automatic shutdown, parallel systems and downsizing.
  • Verify that the equipment is correctly installed.
  • Include an adjustable/variable-speed drive to optimize energy efficiency and reliability for typical operation. VSDs can save as much as 50 percent of a motor system's energy use, help prolong equipment, and give operators greater flexibility over processes.
  • Reduce load requirements through 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 bypasses.
  • Adjust the impeller in pumps. Pumps that fall below 50% efficiency should probably be replaced.
  • Keep motors cool. Overloading, improper supply voltage (high/low), frequent start/stops, poor input power quality and restricted cooling systems all serve to increase motor temperatures.
  • Keep motors clean and lubricated. Bearing failures are the most frequent mechanical cause of motor failure.