A VFD, or Variable Frequency Drive, is a motor controller that adapts energy to gradually shift the motor’s speed, allowing equipment to optimize energy efficiency while maintaining high performance outputs.
Typically, motors have one setting: high speed. Motors are necessary to run all heating, ventilation and air conditioning (HVAC) equipment, like fans, pumps and compressors. However, energy requirements vary among these products. With this new technology, energy outputs can be reconfigured and specified to the exact frequency and voltage consumed for optimal performances.
Other names used for VFDs are VSDs (variable speed drive) and AC (alternating current motors), but they all refer to the same thing. The first ever alternating current drive, or three-phase AC, was credited to be invented by Nikola Tesla in the 1880s. This three-phase motor was revolutionary for alternating levels of energy, but it only had one speed. 100 years later, a reliable, cost-effective method for speed variety within motor drives was introduced.
While his name is often discredited, Finnish electrical engineer Martti Harmoinen designed the first AC motors with the leading Finnish electrical manufacturing company of the time, Strömberg. It was a revolutionary invention to prevent the wear of railway motors that typically used DC (direct current) motors.
Martti Harmoinen (1934-2023). Source: chemistryworld.com.
Harmoinen’s AC motors used a magnetic field sending mechanical energy into the motor. This replaced physical contact of brushes against metal sheets to turn a motor that easily wore down and needed constant attention. To switch from the antiquated DC motors meant to incorporate a tool that would not only save energy, but function in a manner that could be sealed off and reliable to run smoothly for ages.
M100 trains of the Helsinki Metro used the world’s first AC induction motors designed by Strömberg. Source: chemistryworld.com.
Danfoss, a manufacturing company that specializes in the drives, is in the top 10 of global market leaders in VFDs. According to their website, the analytical studies of products within Danfoss show a typical power or fuel savings of 40% with the use of motor drives.
The energy savings occur due to the mathematical phenomenon known as the Cube Law. This law states the power utilized is equivalent to the speed cubed. To understand, picture a motor’s speed reduced by 10%. This motor now has 90% of its flow. To calculate power, you multiply 0.9 x 0.9 x 0.9 to get .73 or 73% of energy saved. Imagine how much more efficient all equipment can become with the specified reduction of power and hybridization of outputs.
Northrich Co. trusts Danfoss for their reliability and purpose to build a better future in HVAC. For more information on the VFD market and how to find one to best-suit your needs, contact Northrich company at 216-581-4750 or go to www.northrich.com.