Demand-Side Management Technology Workshop: Motors · PDF fileDemand-Side Management Technology Workshop: ... Motors and VFD ... Demand-Side Management Technology Workshop: Motors

Demand-Side ManagementTechnology Workshop:

Motors and Variable Frequency Drives

Sponsored by

Basin Electric Power Cooperative

with Western Area Power Administration

www.johnsonconsulting.com1


April 6, 2009

Bismarck, ND

Motors and VFDCase Studies

Cory Fuehrer, NPPD

Dan Slottke, Precise Power Corp.


Dan Slottke, Precise Power Corp. with

Dave La Brie, Precise Power/Husker Power

Mark Tsatsos, Marathon Electric with

Warren Bryan, L & S Electric

Nema Premium EfficientMotor/VFD Case Studies

Increasing Efficiency of Electric MotorsSaves Energy at Research Facility

• Company 3M Center Maplewood, MN

• Product Line Scientific R and D


• Applicable Process Laboratory

• Reductions 10,821,000 kWH (anticipated)

Source: US Dept. of Energy – Energy Efficiency and Renewable Energy

Project Scope:

This energy saving project was conducted at 3MCenter, a 7.5 million square foot facility. Thecompany formed a team that evaluated



company formed a team that evaluatedapproximately 1000 electric motor systems in 29buildings at the 3M Center.


Examples of upgrades include: The reheat watersupply system pumps hot water to the building supplyair reheat coils. The air supply flow to the reheat coilsis constant, so temperature control is achieved byregulating the flow of hot water. The building has fivereheat water supply pumping systems, each with two



reheat water supply pumping systems, each with two7-1/2 hp motors. Energy-efficient motors and VFDswere installed to better match the amount of waterbeing pumped with the system requirements. Inaddition, tests conducted revealed that the systemcould perform satisfactorily with a lower differentialpressure setting across the pump.


Air is supplied to many parts of Building 123 by two50 hp fans. The volume of supply air required varieswith the number of exhaust fans running, which inturn depends on process activity and buildingoccupancy. Fans were run constantly and controlled



occupancy. Fans were run constantly and controlledwith dampers. The team installed a VFD on each fanto control airflow more efficiently and installed anenergy-efficient motor on the one fan that did nothave one.

Project Scope: NCI’s ventilation system uses ninesupply fans (SF’s) and nine return fans (RF’s) tocirculate high humidity air to maintain ambientconditions, cool process machinery, and controlsuspended particulate and airborne fibers.



suspended particulate and airborne fibers.• Company NCI, Fresno, CA• Product Line Textile manufacturing• Applicable Process Raw cotton processing• Reductions 1,600,000 KWh


Project Scope (Cont): While the qualities andvolumes of air supplied and returned from eacharea remain constant in the system, seasonalvariations occasionally cause minor changes in



variations occasionally cause minor changes inthe ventilation rates. After determining that theventilation system’s fans were significantlyoversized, NCI retrofitted 15 of the 18 fans withVFD’s. The remaining fans always ran at full flowand did not need VFD’s.

Results: Installation of the VFD’s reduced theventilation system’s total electricity demandfrom approximately 322 KW to 133 KW, a 59%drop. The energy efficiency gains were possible



drop. The energy efficiency gains were possiblebecause the VFD’s enabled plant personnel tofully open the fan control dampers and reducefan speed. This results in a large drop in motorpower consumption and allows the system tooperate efficiently.

Increasing Efficiency of Electric MotorsSaves Energy at Research Facility

• Company City of Long Beach, CA

• Product Line Utility



• Product Line Utility

• Applicable Process Solid waste to Energy

• Reductions 3,661,200 KWh


Project Scope: After trucks discharge their loads SERRF’s5,000 ton solid waste storage pit, large cranes depositprocessable waste into one of three hoppers, where thewaste is then pushed by hydraulic rams into one of threeidentical boilers. These balance draft boilers combust the



identical boilers. These balance draft boilers combust thesolid waste, converting water flowing through the boilertubes into steam that is used to drive a turbine generator. Inaddition to being equipped with one 100 HP primary air fan,each boiler has a 500 HP induced draft fan on the exhaustside of the boiler. Analysis of the original operating processdemonstrated several key findings.


Project Scope (Cont): First, to meet system requirementsduring startup, shutdown, and normal system operation, theinduced draft fans damper settings covered the entire rangefrom closed to 100 percent open. The average fan inletdamper setting, however, was 47% open.

The New System: To increase system efficiency, the plant



The New System: To increase system efficiency, the plantretrofitted each of the three induced draft fan systems withVFD’s designed to operate with the original 500 HP inductionmotors. This modification enabled plant operators tocontinuously modulate induced draft fan speed to maintainthe boiler draft set point and allowed fan inlet dampers to beopened to 100 %, eliminating pressure drop due to throttling.Source: US Dept. of Energy – Energy Efficiency and Renewable Energy

Lunch and TechnologyDemonstrations


Demand-Side ManagementTechnology Workshop:

Motors and Variable Frequency Drives

Sponsored by

Basin Electric Power Cooperative




April 6, 2009

Bismarck, ND

Demand-Side Management Technology Workshop: Motors · PDF fileDemand-Side Management Technology Workshop: ... Motors and VFD ... Demand-Side Management Technology Workshop: Motors

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