Variable-frequency drives (VFDs)—also referred to as variable-speed or adjustable-speed drives—allow induction-motor-driven loads such as condenser fans and brine pumps to operate at rotational speeds.

VFDs are used in applications ranging from small appliances to large compressors. About 25% of the world’s electrical energy is consumed by electric motors in industrial applications, which can be more efficient when using VFDs in centrifugal load service.

A variable speed drive controls motor speed and torque by varying the motor input voltage and frequency. Variable speed drives are expensive, yet the most efficient means of operation, as they match pump operation with the ice surface needs.

By controlling motor speed to correspond with varying load requirements, retrofitting electric motors with VFD controls can increase motor energy efficiency—in some cases by as much as 50%.

VFDs can also improve power factor and process precision, and they can deliver other performance enhancements and non-energy benefits such as motor soft starting and over-speed operating capabilities.

Using VFDs can also helps eliminate the need to use expensive, energy-wasting mechanical throttling devices like control valves or outlet dampers.

Benefits: 

  • Energy savings for some fan and pump applications
  • Improved process control and regulation
  • Precision process control for motors used in industrial applications
  • Built-in power-factor correction
  • Bypass capability to protect equipment from damage caused by power outages and emergencies
  • Protection from overload currents
  • Safe, precision-controlled motor acceleration

Savings:

  • Electricity
  • CO2 emissions

Web resources: 

 

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