175H9100 by Danfoss

The 175H9100 variable frequency drive is manufactured by Danfoss for the VLT 3000 Variable Speed Drives series. It converts fixed-frequency mains power into a regulated output so that a three-phase induction motor can accelerate, decelerate, and hold constant speed in automated conveyors, pumps, and fan systems. By modulating both voltage and frequency, the drive lets the system match motor torque to the actual load, lowering energy consumption and mechanical wear in continuous-duty production cells. Its electronic design also filters harmonic currents while supporting long motor leads in distributed control panels.

The drive's pulse-width-modulated output is governed by a carrier frequency that can be set as high as 4.5 kHz, allowing a balance between audible noise and switching efficiency. At the output terminals, it delivers a rated phase-to-phase voltage of 380/400/415 V, so motors designed for these network levels can run without derating. Under nominal loading, the displacement power factor reaches 0.9/1.0, indicating minimal reactive current. Unscreened motor cable runs up to 300 m are permissible, while screened leads of 150 m can be used when the switching frequency stays at or below the stated limit. The inverter's typical shaft output of 11.0 kW suits medium-sized process pumps and material-handling drives used on factory floors.

Incoming power is accepted across three phases at 3 × 380/400/415 V AC (±10%), giving margin for utility fluctuations without tripping the converter. Internally, the unit synchronizes to a line frequency of 50/60 Hz and can synthesize motor frequencies of 50/60/87/100 Hz, enabling either constant-torque or constant-power regulation. To avoid premature wear on upstream contactors, the control electronics limit supply reconnections to a maximum of 1 time per minute. Once energized, all speed changes are handled electronically rather than by repeated supply switching. The unit can be used in central motor control centers or field enclosures.