The variable speed drive (VSD) compressor is one of the most energy efficient compressor designs in the compressed air industry and has been since its introduction in 1994. Fitted with an intelligent drive system, a variable speed drive compressor continuously changes the motor speed to match air demand. This also eliminates the compressor running in an unloaded state. This simple concept yields significant energy savings for manufacturers in a variety of industries.
How Does the VSD Work?
The compressor measures the pressure in the air system and the variable speed drive adjusts the speed of the motor to match the air demand in order to maintain the system pressure. This allows the pressure band of the system to be maintained within narrow tolerances. The motor speed of the compressor is regulated by frequency conversion, which results in the variation of air flow. With the addition of advanced electronic controls, the delivery pressure is kept within a + 1.5 psi pressure band, rather than the conventional 10-15 psig pressure band used on inlet controls for non-VSD equipment. Therefore, a lower air compressor delivery pressure can be used to maintain the required minimum working pressure of the system, resulting in increased energy savings and profitability.
Additionally, the converter in the VSD system performs a “soft” start/stop operation by automatically controlling both acceleration and deceleration levels, thus eliminating amperage peaks which could result in penalties from your utility company. Eliminating peaks also protects electrical and mechanical components from the stresses that can shorten the life of an air compressor.
By varying the speed of its drive motor as air demand decreases, the VSD lowers the delivered air flow as well as the electrical power consumption. Properly sized VSD compressors offer manufacturers the ability to fine tune the compressors output to fluctuating compressed air demands.
New Technology Eliminates Disadvantages
The new technology used in the GA 7-37 VSD+ eliminates most challenges associated with the original VSD design. The VSD+ features a vertical drive shaft where the motor and drive train are completely enclosed, resulting in an IP55 enclosure rating for protection against dust, debris and water, thus eliminating the reliability challenges associated with operating a VSD compressor in dusty or dirty conditions.
Due to many small changes in the design, VSD compressors are now more robust, reliable and energy efficient than ever. This new technology can potentially reduce energy consumption by 50 percent, which reduces the payback time and increases the return on investment over the lifetime of the compressor.
To learn more about VSD+ technology, visit the Atlas Copco GA 7-37 VSD+ product page.
