178B4811 by Danfoss

The 178B4811 is an adjustable-speed drive assembled by Danfoss for the VLT 6000 HVAC Drives series. As a dedicated HVAC drive, it modulates three-phase induction motors in air-handling units, pumps, or chillers to match system demand and reduce energy use in building automation. The unit belongs to the 100 HP class and is commonly installed in mechanical rooms where cabinet space and code requirements favor compact enclosures. This type of variable-speed control also helps fans and pumps avoid running at fixed speed when the load is low.

It is powered from a 380-460 VAC mains supply and converts that line input into a variable output frequency suitable for centrifugal loads. The drive's thermal and current capacity is matched to a 75 kW / 100 HP motor, allowing full-load operation without external derating under normal indoor conditions. Mechanical integration is aided by the Compact NEMA 1 housing, which permits panel mounting inside conditioned spaces while providing finger-safe touch protection. Operators configure setpoints through the integrated LCP (Local Control Panel), which offers parameter access, status information, and fault readout at the drive. Electrical noise suppression must be handled externally because the model is supplied without filter for radio-frequency interference control.

The unit is supplied as a standard unit with no custom plug-in boards, reflecting the fieldbus selection of no options for network communication and an application setup that omits extra I/O beyond the base drive arrangement. The ordering code marks the intended duty as Graham, indicating the application profile assigned to this version. This layout suits installations that rely on the standard control terminals rather than supplemental communication cards. There is no coating on the circuit boards, so the drive is best suited for clean, indoor control-room conditions where humidity is controlled and condensation is avoided.