Variable speed (VSD) rotary screw air compressors

Choose a variable speed air compressor for superior part-load performance

VSD/VFD

SFC15 air system

Many of Kaeser's rotary screw compressors are available with variable speed drive using Siemens drive technology. Kaeser's engineers have optimized the airend design to accommodate a wide flow range with unmatched efficiency. The drive motor and Sigma Profile airend operate at low speeds, resulting in exceptional reliability and long life.

Advantages of variable frequency drives

  • Meet varying loads:
    Most compressed air systems have varying loads and it is often more effective and efficient to apply multiple compressors to meet changing demand. In cases where the demand profile changes rapidly and frequently, variable frequency drive compressors may be recommended. By varying the frequency of the input electricity to the motor, these compressors speed up and down to match their air output to your demand.
  • Precise pressure control:
    Kaeser's SFC design includes highly accurate sensors to maintain stable pressure (± 1.5 psig), without wasting air by over-pressurizing the system. This also increases reliability and product quality in your plant.
  • Superior part-load performance:
    Kaeser's SFC units have superior part-load performance and make great trim machines. They can be easily integrated into a multi-compressor system to provide faster response to variations in air consumption. At the same time, they can reduce electricity costs since their electrical consumption varies directly with air production.
  • Soft start:
    Kaeser's frequency drives are the ultimate soft starter for your motor using the lowest start-up current. They eliminate heat spikes in motor windings, allowing unlimited motor starts. Of course, frequency drives usually have fewer starts/stops, which means less frequent loading and unloading, for less wear and tear on important mechanical parts.

10 to 30 hp variable speed compressors with belt drive: SFC 8 - 22S models

Model Rated Motor Power [hp] Min. Capacity [cfm] Max. Capacity [cfm]
SFC 8 10 12 48
SFC 11 15 22 72
SFC 15 20 28 95
SFC 18S 25 33 119
SFC 22S 30 33 141


Flows at 125 psig

30 to 700 hp variable speed rotary screw compressors with direct drive: SFC 22 - 515 models

Model Rated Motor Power [hp] Min. Capacity [cfm] Max. Capacity [cfm]
SFC 22 30 37 154
SFC 30S 40 37 174
SFC 30 40 48 206
SFC 37 50 54 241
SFC 45S 60 69 273
SFC 45 60 70 300
SFC 55 75 80 360
SFC 75S 100 101 440
SFC 90S 100 121 492
SFC 110S 125 135 587
SFC 75 100 127 553
SFC 90 125 127 655
SFC 110 150 153 752
SFC 132S 175 194 859
SFC 132 200 194 918
SFC 160 250 240 1090
SFC 200 270 300 1257
SFC 250 340 370 1439
SFC 315S 350 370 1742
SFC 315 450 465 2057
SFC 410 590 363 2537
SFC 515 700 412 3117


Flows at 125 psig

75 to 450 hp variable speed compressors, oil-free: CSG 90-2 SFC - FSG 500-2 SFC models

Model Rated Motor Power [hp] Min. Capacity [cfm] Max. Capacity [cfm]
CSG 90-2 SFC 75 126 318
CSG 120-2 SFC 100 144 427
CSG 130-2 SFC 125 183 468
DSG 180-2 SFC 150 312 665
DSG 220-2 SFC 175 320 773
DSG 260-2 SFC 200 346 911
DSG 290-2 SFC 250 418 1058
FSG 420-2 SFC 350 604 1430
FSG 500-2 SFC 450 663 1710


Flows at 125 psig

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