178B2106 by Danfoss

The 178B2106 variable frequency drive is manufactured by Danfoss and belongs to the VLT 6000 HVAC Drives series. Designed for building automation, this drive adjusts the speed of three-phase induction motors so fans, pumps, and compressors deliver only the capacity demanded by the control loop. By regulating motor frequency and voltage, it helps lower energy use, minimize mechanical stress, and maintain stable environmental conditions in industrial and commercial facilities while fitting standard electrical enclosures used in air-handling units. Its operating concept is intended for HVAC service where airflow or fluid demand changes throughout the day.

It accepts a mains supply between 380-460 VAC, covering the common 400 V class widely installed in process plants. The drive's power section is rated at 30 kW / 40 HP, providing adequate headroom for medium-duty ventilation zones without oversizing. A compact NEMA 1 enclosure supports wall or panel mounting in clean indoor locations while offering touch safety and conduit knockouts. Building management integration is simplified by LonWorks free-topology communication, which operates on a polarity-insensitive twisted-pair network that can be wired in bus or star layouts. The drive is supplied with an LCP, and the front-mounted keypad displays operating frequency, current, and alarms while also providing access to parameter settings.

The drive is delivered as a standard unit, and it is supplied with no factory-installed options. It ships without a filter, so electromagnetic compatibility can be tailored with external RFI components when required instead of being fixed at the factory. The control boards are produced with no protective coating, so the inverter should be installed in spaces where airborne contaminants and condensation are limited. This arrangement leaves line-side filtering and board protection dependent on site requirements. It also aligns with the Graham application reference for centrifugal fan or pump retrofit projects.