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  • IEC 60034-31:2009

  • 31 –

2/1554/CD

70'000

2000 operating hours per year 4000 6000 8000

Source: de Almeida, EuP lot 11, 2008

60'000

50'000

Life Cycle Cost (Euro)

40'000

30'000

20'000

10'000

0

IE1

IE2

IE3

Figure 13

Life cycle cost analysis of 11 kW motor Source: EuP Lot 11, 2008

In several studies also the environmental impact of high efficiency motors and variable drives have been studied. The additional material used in the production of the more energy efficient equipment is reflected in higher purchase price. The studies confirm that if the life cycle cost is lower for higher efficiency motors this is also true when considering the environmental impact.

9 Maintenance

The electric motor generally needs little maintenance, therefore proper maintenance is often forgotten. There are a number of common abnormalities which have an adverse effect on a motor's performance:

  • a)

    insufficient ventilation

  • b)

    high ambient temperatures

  • c)

    mechanical misalignment

  • d)

    improper V-belt application

  • e)

    improper lubrication

  • f)

    excessive moisture

  • g)

    contamination

  • h)

    sustained overload

  • i)

    abnormal voltage

  • j)

    extreme voltage unbalance (single-phasing)

Insufficient ventilation or high ambient temperatures result in higher resistance in the winding. On the average, the efficiency of a motor will decay by 0.2 to 1.0 percentage points from room temperature to its operating temperature. Furthermore, excessive temperature rises caused by poor maintenance or misapplication reduces the operating life of the motor and increases energy consumption. Sometimes additional friction gradually develops within the driven machine. This could be caused by a buildup of dust on a fan, the wearing of parts, misalignment of gears or belts, or insufficient lubrication in the driven machine. These conditions cause the driven machine to become less efficient, which reduces system efficiency and increases energy consumption. To

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