178B0768 by Danfoss

The 178B0768 is an AC variable-frequency drive built by Danfoss for the VLT 6000 HVAC Drives series. In building automation, it regulates fan and pump speed so airflow or water flow can match real-time demand rather than running continuously at full output. This helps reduce mechanical wear in air-handling units, chillers, and boiler circuits while also supporting steadier control of comfort and process conditions across the system.

This standard unit is designed for three-phase mains from 380-460 VAC, a range that fits many commercial and industrial power systems without an external transformer. The power stage is rated at 4.0 kW, which corresponds to 5.0 HP for compatible motor applications. Its book-style IP20 housing is intended for installation inside an electrical enclosure, where panel airflow can carry heat away from the drive. Control communication with a central building management system is handled through Profibus DP V1, allowing cyclic exchange of commands and operating status over the fieldbus network. Front access programming is not available because the drive is supplied without an LCP, so setup and parameter changes are handled through remote tools or a temporary control panel. Conducted emissions are reduced by the integrated Class A1 and B filter, which helps limit electrical noise in surrounding equipment.

The drive is configured for HVAC duty, which suits variable-torque loads such as supply fans, return fans, and circulation pumps. The electronics are supplied with no protective coating, so the unit is better suited to clean, dry electrical enclosures than to areas with condensation or corrosive vapors. This installation approach is common in indoor mechanical rooms, where the panel environment is controlled and the drive can respond smoothly to changing ventilation or water-flow demand throughout normal operation.