178B1185 by Danfoss

The 178B1185 is an AC variable-frequency drive manufactured by Danfoss and supplied within the VLT 6000 HVAC Drives series. It adjusts the speed of induction motors used on fans, pumps, and compressors in building automation systems, helping airflow and fluid pressure track operating demand. Instead of running connected motors only at full speed, the drive varies output frequency and voltage to better match the load. This makes it suitable for systems that need gradual speed changes rather than repeated across-the-line motor starting.

The drive accepts a three-phase supply of 380-460 VAC, allowing direct connection to common commercial power systems without an input transformer. Its inverter section can deliver up to 18.5 kW or 25 HP, which suits medium-duty air-handling units and chilled-water pumps. Conducted emissions are limited by an integrated Class A1 and B filter, helping the installation meet EMC requirements in many buildings. Operators can adjust set points and view alarms through an LCP (Local Control Panel), so routine interaction does not require a separate external programmer. The communication slot and application board are supplied without installed options, leaving the unit in a straightforward base configuration. The output section supports smooth speed adjustment as demand changes through normal operation.

The enclosure uses a compact IP20 housing, which fits shallow panels and provides basic touch protection when installed inside a ventilated cabinet. All power boards are supplied with a protective coating to help guard against moisture and airborne contaminants often found in rooftop or plant-room environments. The control package supports HVAC functions, including proportional-integral regulation for pressure or temperature control without additional PLC logic for these tasks. It is supplied as a standard unit, so it follows the baseline configuration used for this product line. This arrangement keeps local control, motor-speed regulation, and cabinet installation requirements easy to understand during integration.