Energy-Efficient Motors

Energy-Efficient Motors

US Energy Consumption Facts

Share of Energy Consumed by Major Sectors of the Economy, 2008
Source: Energy Information Administration, Annual Energy Review 2008
Over 33% of the energy that goes into energy systems is lost during:

  • Generation of steam and power
  • Distribution
  • Conversion of energy into useful work

Image courtesy of Siemens Industry, Inc.Energy Efficiency: Market Barriers (Perceptions)

  • Reluctance to change a working process
  • Pay-back time is too long
  • Shortage of capital
  • “No measurement” culture
  • Lack of correct definitions system efficiency
  • Not all parties in the supply chain are motivated
  • Lack of management time
  • Confusion about top line vs. bottom line

Energy-efficient Drive Technology: The most effective way of saving costs

Energy-efficient drive systems can assist companies in a number of ways. They help to reduce production costs, improve the return on investment, and lower CO2 emissions.
Image courtesy of Siemens Industry, Inc.Particularly in energy-intensive sectors, using mechanically controlled pumps, fans and compressors or drives in continuous operation, switching to energy saving systems has direct benefits. Such investments can be recouped in a very short time; within just a few short months for some applications.

Remember: it’s the entire operating life of your equipment, not the procurement price that makes the difference.

Changing the speed rather than mechanically controlling the flow
Mechanical control methods have many hidden disadvantages. For example, the motor runs continuously at the speed required for the maximum delivery rate, which is rarely needed in practice. Additionally, the throttles and valves lose energy and cause high temperatures and vibration levels which can have a negative impact on the drive and production operation.

Variable-speed drives with inverters offer an economic alternative for a number of reasons:

  • They can be controlled much more quickly and precisely
  • By adapting the flow rate directly to actual requirements, no more energy is wasted
  • Savings of up to 60% – even up to 70% in energy-intensive applications – can be achieved

Reducing costs, improving processes
Compared with mechanical controllers, variable speed drives reduce not only energy costs, but also maintenance and service costs. They also improve process quality and raise productivity.

Current spikes during motor start-up and heavy torque surges are a thing of the past; as are pressure waves in pipe systems, cavitation and vibration, which can cause lasting damage to plants. Smooth starting and coasting down is gentle on the mechanics and prolongs the lifetime of the entire drive train considerably.

Energy Checklist: Will it Pay Off?

Find out whether introducing energy-efficient drive systems will pay for themselves. Analyze your systems using the following checklist. The more points apply, the higher is your savings potential:

Look at your primary processes.

  • Do they still use mechanical flow control?
  • Do your motors run uninterrupted for long periods?
  • Do you have many drives that run in partial load operation?
  • Do you run processes where large loads are frequently decelerated?

What secondary processes and building installations do you have?

  • Is your factory equipped with air extraction and ventilation?
  • Do you operate pumps that run permanently or frequently with a partial load?
  • Are you familiar with all your auxiliary processes (conveyor belts, etc.)?
  • Is it possible to shut down your auxiliary processes at the weekend?

What about your electricity bill?

  • Do you want to reduce the energy costs of your plant?
  • Have you ever considered a holistic system analysis of your drives, which looks at everything from the energy management to the pipe lagging?
  • Are you paying for reactive power?
  • Are you paying Power Factor penalties?

Siemens energy-saving portfolio at a glance:

  • A comprehensive range of energy-efficient motors in almost every Siemens Industry, Inc & IBTperformance class, with up to 40 % lower power losses than standard motors
  • The most comprehensive range of inverters available on the market, which depending on the application, can result in electricity savings of up to 70 %
  • Regenerative feedback inverters with innovative infeed technology, which feed any braking energy generated back into the line supply and in the case of hoisting applications, for example, save up to 50 % energy

Siemens software tool, SinaSave, can be downloaded free of charge. SinaSave identifies savings potential in your application and shows how fast an investment in an energy-efficient motor or an inverter will pay for itself. Visit to download SinaSave.

How SinaSave Works

SinaSave has been designed to select an energy efficient motor in on-line operation or an inverter for variable-speed and therefore energy-saving operation.
Image courtesy of Siemens Industry, IncWhen connected directly to the line supply, you can calculate the cost-saving and payback period of our energy-saving motors class EFF1 (IE2) or NEMA Premium based on three comparison cases: compared to EFF2 (IE1) or EPAct motors, individually selected and known motors, or compared with known motors within a complete plant or system assessment.

In inverter operation, SinaSave looks at all the necessary system-specific parameters as well as values required for the process. For example: the flow rate of pumps, the density of the medium and the efficiency of the pumps, fans, and compressors of the entire system.

Other basic data the program draws on are the number of working days and shifts as well as the delivery profile determining the energy-saving effect over the day and the year.

Based on plant-specific data, the program derives a suitable drive system, calculates the price of a suitable inverter and derives the energy requirement of the variable-speed drive system as compared with all potential alternative concepts.

In addition to high-efficiency motors (IE2), SinaSave also includes low-voltage and medium-voltage inverters that are predestined for pump and fan applications. Further, the motor side has been supplemented by mechanical system analyses. High-torque motors have also been newly integrated into SinaSave.

User-friendly functions, such as the automatic update function, an up-to-date currency table and improved export functions – such as sending pdf e-mail from SinaSave – round off the contents of the energy-saving tool.

For further information contact an IBT Product Specialist.

Graphics and portions of this article are reprinted with permission of Siemens Industry, Inc.


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