178B3435 by Danfoss

The 178B3435 is an adjustable-speed controller manufactured by Danfoss within the VLT 6000 HVAC Drives series. As an HVAC drive, it modulates the speed of induction motors that power supply and exhaust fans, pumps, and similar building-service loads, helping automation systems match airflow or pressure demand while reducing energy consumption during partial-load operation. The drive interfaces with building-management inputs through its local panel or discrete terminals, and it is commonly used across air-handling units, chillers, and cooling towers. By varying motor output to suit changing load conditions, the controller also helps reduce unnecessary mechanical stress in ventilation and circulation equipment.

It accepts a three-phase input of 380-460 VAC, so it is compatible with most industrial mains without an external transformer. The electronics are housed in a Compact NEMA 1 enclosure, allowing wall or panel installation in clean electrical rooms while providing finger protection against live parts. Operators adjust parameters through the integrated display described as with an LCP, which provides real-time status information and local setup access. Radio-frequency emissions are not attenuated internally because the unit is supplied without a filter, so installations that require conducted-emission suppression need an external device. Its control board has no coating, so the drive is intended for locations where airborne contaminants and condensation are not expected.

For networked buildings that rely on BACnet, LonWorks, or PROFIBUS, the communication slot is shipped with no options, so any fieldbus interface must be added later if remote access is required. The power stage and control logic follow the baseline configuration of a standard unit. The device includes motor-ramp functions, automatic energy optimization, and sleep mode tailored to variable-torque ventilation loads. These functions support fan and pump applications that often operate for long periods at reduced demand. The internal components are intended for mechanical rooms that meet the stated ambient and cleanliness limits.