178B3440 by Danfoss

The 178B3440 is a low-voltage AC drive manufactured by Danfoss as part of the VLT 2800 Low Voltage Drives series. Designed for decentralized motor control in process lines, the unit uses pulse-width modulation to vary output frequency and torque, allowing precise speed regulation of small induction motors. Its compact housing is intended for installation in electrical cabinets, where the drive acts as an intermediary between mains power and the motor while handling startup, ramping, and basic protection functions required in automated equipment.

Electrical compatibility centers on a supply window of 200-240 V AC, so the inverter can be linked directly to standard low-voltage utility feeds without an isolation transformer. The power section is wired for single-phase input, which matches installations where only one live conductor and neutral are available. An IP20 protection rating means finger-safe shielding is provided, but the cabinet must furnish additional sealing. The slim book-style enclosure allows multiple drives to mount side by side on a DIN rail, saving panel width. For supervisory control, an optional communication card enables connection to a DeviceNet network, letting a PLC read status words and issue speed references over the fieldbus.

The front panel features a built-in display (SLCP) that shows operating frequency, current, and alarm codes, eliminating the need for an external keypad during setup. The drive has no application option, so it uses a general-purpose configuration rather than a pre-tuned pump, fan, or HVAC profile. Surfaces are supplied without coating, which suits clean indoor switchboards where conformal varnish is unnecessary. The dedicated application tag is Process, and its parameter set favors linear torque response and steady speed under fluctuating loads found in mixers, feeders, and dosing augers.