178B0046 by Danfoss

The 178B0046 is an AC variable-frequency drive assembled by Danfoss for the VLT 6000 HVAC Drives series. Designed as a motor speed regulator in large air-handling units, chillers, and supply fans, the unit modulates three-phase induction motors to match thermal load while lowering energy use in building automation. It forms a central part of automated ventilation loops, receiving setpoints from building management systems and adjusting compressor or blower torque accordingly. With its compact construction, the drive eases installation inside electrical rooms that already host contactors and protective equipment.

The input bus accepts line voltages from 380-460 VAC, allowing the same model to serve both 400 V and 460 V distribution networks without transformer steps. Rated output is 45 kW/60 HP, so a single frame can cover mid-size fan wheels or primary chilled-water pumps. The housing is a compact IP 20 enclosure, and this touch-safe design protects against solid objects greater than 12.5 mm while remaining vented for panel-mount cooling. An onboard Local Control Panel presents parameter codes, start-stop keys, and an alphanumeric readout for local setup. The unit has standard hardware, meaning no additional I/O cards are fitted and wiring follows the base terminal plan.

Because the drive targets HVAC duty cycles, it already contains predefined macros for supply-air, return-air, and pump control that shorten setup time. Electromagnetic compliance components can be added later, but this catalog number is supplied without an RFI filter, letting users choose external filters sized to cable length and emission class. The circuit boards are delivered without conformal coating, so installation should avoid high-humidity zones or corrosive atmospheres unless additional protection is provided. Network integration is optional, and the unit has no fieldbus option, making it suitable for stand-alone loops or hardwired analog commands.