Energy Reduction

Motors and Power Systems

When equipment failure takes place, you first need to determine if it happened as a result of power quality issues or the equipment itself.

  • When did the problem occur?
  • What equipment failed?
  • Was there nearby interference?
  • Are there capacitor banks nearby?
  • Is there any new equipment in the system? 

If the issue involves power quality, there are a number of factors which might be at fault, including transients, harmonics, voltage sags or imbalances, and so on. To ensure that your facility's power needs are continuously being met, it's important to regularly inspect equipment and electrical systems for power quality issues. By using an RMS volt meter, you can monitor voltage, which should range from +6 to -8 of nominal voltage.

 

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Power Quality Protection Program

It's also important to have a Power Quality Protection Program in place. The goal is to protect equipment, data, and operation of your facility, and a good plan can pay for itself in a short time through reduced downtime and increased productivity. Your plan could include a number of solutions, including:

  • Transient voltage surge protectors: least expensive form of power protection that protects equipment by clamping off excess voltage. You can protect from transients using transient voltage surge suppressors, residential class surge suppressor panels, or receptacles. These can help reduce damage, disruption, and destruction of electrical equipment.
  • Standby power supplies:provide power from a generator, fuel cell, or separate distribution line for up to several hours.
  • Filtering devices: filter electrical noise to prevent software errors.
  • Voltage regulators: help maintain a constant voltage output, but do not provide protection against spikes.
  • Isolation transformers: suppress electrical noise, but do not protect against harmonics.
  • Phase monitors: alert you with an audio or visual alarm when they detect a phase loss or complete shutdown. Phase monitors are inexpensive and easy to install.
  • Uninterruptible power supplies: provide the most complete protection for a short time period. Uninterruptible power supply systems provides backup power, stable frequency and stage shift during power outages and disturbances. The three types of UPS systems include:  

Off-line: used for single applications, when minimum protection is needed.   

Line interactive: consists of a constant voltage transformer between the utility power supply and load and can provide brief power during an outage or disturbance.  

Online: provide the highest level of protections and the most stable and regulated output frequency.

Use combined heat and power systems

This provides onsite power generation that can recycle waste heat from electricity generated in power plants and use it to generate thermal or mechanical energy. Aside from improved energy efficiency, there are financial incentives, including The Energy Improvement and Extension Act of 2008.

Summary of Cogeneration Technology

Technology

Reciprocating Engines

Micro turbines

Gas Turbines

Fuel Cells

Available Sizes

Up to 6 MW

30 kW-350 kW

500 kW-40 MW

200 kW-250 kW

Cost per kW

$800-$1,200

$1,300-$1,500

$800-$1,500

$2,700-$5,300

Energy Efficiency

70%-80%

50%-70%

70%-80%

60%-80%


[1] where cfm=cubic feet per minute, HDD=annual heating degree days (mean difference between 65°F and the average daily temperature), EF=heat exchanger efficiency, and 25.92=constant for specific heat and weight of air

Additional strategies

You can also make sure to separate communication and electrical lines. This helps ensure that the two are not carried in the same conduit, which in turn reduces potential for loss in productivity.

Utilizing distributed generation (multiple generators) over centrally generated power in commercial facilities can also increase power reliability, while also reducing energy use and lowering emissions. DG systems are now used to reduce peak demand charges. Equipment options include:

  • Gas turbines: compact and easy to operate
  • Reciprocating engines: small and have a low capital cost
  • Micro turbines: operate with great efficiency and have lower emissions
  • Fuel cells: compact, and cleaner and quieter compared to micro turbines
  • Energy storage devices: provide addition energy during peak operating times.

You can also improve system reliability and lower maintenance and energy usage by utilizing variable speed drivers and series of smaller pumps to match facility operational needs. By replacing water impellers, pumps and motors with appropriate, smaller-sized equipment, you can reduce pump power to save energy and water, while still meeting your water needs.

For further details on pump efficiency, refer to the no-cost Pump System Assessment Tool, which evaluates pump system performance.

 

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Motors

Select the most energy-efficient motor for your facility price range. Before purchasing new motors, examine your existing motors to determine the benefits of upgrading. Implement a motor efficiency program to measure voltage, amperage, power factor, and operating speed to decide whether to replace motors immediately, or at time of failure. Most energy efficient models provide a return on investment within two years.

There are a number of different truck designs which you might use, such as standard, reach, order pickers and pallet trucks. Consider the truck design options that best suit your facility needs. Truck motors may be:

  • Electric: used exclusively for indoor environments and can use multiple rechargeable batteries. Use AC motors for great efficiency.
  • Liquid propane: used for both indoor and outdoor work and allow for quick exchange of propane tanks.
  • Gasoline: used in construction settings.

There are several design factors that increase performance, which you can consider when choosing a new motor:

  • Longer core and lower-electrical-loss steel use
  • Thinner stator laminations and more copper in the windings
  • Improved bearings
  • Smaller, aerodynamic, cooling fans.

 

Open Efficiency (%)

Enclosed Efficiency (%)

Horsepower

3,600

1,800

1,200

3,600

1,800

1,200

2

84

84

85.5

84

84

86.5

5

85.5

87.5

87.5

87.5

87.5

87.5

10

88.5

89.5

90.2

89.5

89.5

89.5

20

90.2

91

91

90.2

91

90.2

50

92.4

93

93

92.4

93

93

100

93

94.1

94.1

93.6

94.5

94.1

200

94.5

95

94.5

95

95

95

Note: Open motors allow free air movement, while enclosed motors restrict air infiltration.

Consider variable frequency drives or two-speed motors

Use VFD to efficiently modulate motor output and make it practical to use precise motor speed in a variety of applications. This reduces electricity consumption by up to 50 percent in escalators, elevators, pumps, fans, and other applications.

VFDs feature fewer moving parts, resulting in less maintenance and easier installation.