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Variable Frequency Drive Screw Compressors

Kaeser’s Sigma Frequency Control (SFC) compressors combine our Sigma Profile airends and revolutionary Sigma Control system with the latest in variable frequency drive (VFD) technology. Kaeser uses large, optimized airends turning at slower speeds for more efficient performance across the entire speed range.


Models:  SFC 8 to 515
Horsepower: 10  to 700 hp (8 to 515 kW)
Capacities: 10 to 3037 cfm
Standard pressures: 80 to 217 psig



Soft starts

SFC units go from zero to full load without current spikes or excess heat rise.  This allows unlimited motor starts, and since the SFC drive yields a “near unity power factor,”  power factor penalties are also eliminated.



Precise pressure control
SFC compressors precisely control system pressure to ±2 psig using highly accurate sensors and the Sigma Control System to control motor speed. This eliminates “overpressurizing” and increases energy savings – after all every 2 psig saved in overpressurizing reduces power consumption by 1%!



Superior frequency drive system technology
SFC drive systems feature electromagnetic interface (EMI) filters, contactors for galvanic separation and line reactors for superior protection.  Drive cabinet cooling fans maintain proper operating temperatures even under extreme ambient conditions.



EMI filter
SFC drive systems are designed with an electromagnetic interference filter that eliminates or isolates all feedback, and prevents harmonic distortion from entering the plant’s electrical grid.

ModelRated Motor PowerMin. Capacity at 460V, 110 psigMax. Capacity at 460V, 110 psig
SFC 8 / 8T10 hp13 cfm48 cfm
SFC 11 /11T15 hp22 cfm76 cfm
SFC 15 / 15T20 hp29 cfm98 cfm
SFC 18S /18ST25 hp33 cfm113 cfm
SFC 18 / 18T25 hp24 cfm130 cfm
SFC 22 / 22T30 hp29 cfm157 cfm
SFC 30S / 30ST40 hp37 cfm182 cfm
SFC 30 / 30T40 hp46 cfm213 cfm
SFC 37 / 37T50 hp54 cfm254 cfm
SFC 45S / 45ST60 hp69 cfm288 cfm
SFC 45 / 45T60 hp69 cfm310 cfm
SFC 55 / 55T75 hp77 cfm374 cfm
SFC 75S / 75ST100 hp100 cfm463 cfm
SFC 90S / 90ST100 hp120 cfm509 cfm
SFC 110S / 110ST125 hp136 cfm618 cfm
SFC 75 / 75T100 hp127 cfm559 cfm
SFC 90 / 90T125 hp127 cfm627 cfm
SFC 110 / 110T 150 hp150 cfm735 cfm
SFC 132S / 132ST175 hp209 cfm830 cfm
SFC 132200 hp209 cfm919 cfm
SFC 160250 hp230 cfm1074 cfm
SFC 200270 hp303 cfm1305 cfm
SFC 250340 hp358 cfm1466 cfm
SFC 315450 hp470 cfm2091 cfm
SFC 410590 hp413 cfm2624 cfm
SFC 515700 hp417 cfm3037 cfm