Variable Speed Rotary Screw Air Compressors

Not all rotary screw compressors are variable speed — they come in both fixed-speed and variable-speed configurations. Variable Speed Drive (VSD) rotary screw compressors, such as the Gardner Denver LRS Series, continuously adjust motor RPM to match fluctuating air demand. This eliminates the energy waste of loading and unloading cycles, making them the preferred choice for facilities with varying compressed air requirements.

Rotary screw and helical screw compressors refer to the same fundamental technology — the 'helical' describes the profile of the screw rotors used inside the airend. Rotary screw compressors are generally superior to reciprocating (piston) compressors for continuous industrial use, offering higher duty cycles, lower noise, better energy efficiency at variable loads, and longer service life with minimal maintenance.

Variable speed rotary screw compressors can reduce energy consumption by 30–50% compared to fixed-speed models when air demand fluctuates. The LRS Series and EnviroAire TVS achieve these savings by precisely matching motor speed to demand, eliminating the energy penalty of constant loading and unloading. Facilities operating between 40–75% of full load see the greatest savings.

Gardner Denver variable speed rotary screw compressors cover a wide pressure range to suit diverse industrial applications. The LRS Series operates from 75–190 PSIG, the Electra TS/TSV covers 100–200 PSIG, and the oil-free EnviroAire TVS delivers up to 145 PSIG. This range accommodates general manufacturing, food and beverage, pharmaceutical, and automotive applications.

Oil-flooded variable speed compressors (like the LRS Series) use lubricant within the compression chamber for sealing and cooling, then separate it before air delivery — suitable for most general industrial uses. Oil-free models (like the EnviroAire TVS) achieve ISO 8573-1 CLASS 0 certification with zero oil carryover, making them essential for food, pharmaceutical, electronics, and automotive paint applications where contamination is unacceptable.

Gardner Denver offers industry-leading warranty programs. Standard coverage includes a 1–2 year package warranty. The Platinum 10-Year Extended Warranty covers airend parts for 10 years and major components for 5 years. The Platinum+ Full Package Warranty provides a 5-year renewable service agreement covering wear items, package components, and labor through factory-trained authorized distributors, provided maintenance schedules are followed.