178B2091 by Danfoss

The 178B2091 is a decentralized frequency converter manufactured by Danfoss and supplied in the FCD 300 Micro Drives series. Mounted close to the motor, it regulates speed and torque in processing lines where localized control reduces cabinet wiring and keeps the control loop near the driven load. This arrangement is useful on conveyors, pumps, and distributed machine sections where local mounting reduces long motor leads and simplifies panel layout. By combining power electronics and fieldbus communication in one sealed housing, the unit supports distributed drive layouts in wet or dusty industrial areas without requiring a large central cabinet for every axis.

For power access, the drive accepts a three-phase input of 3 x 380-480 V, matching common plant distribution voltages without an autotransformer. Its inverter is rated at 0.75 kW, which corresponds to 1.0 HP. This input range supports use in both 400 V and 480 V class systems commonly found in industrial facilities. The polyester-coated aluminum enclosure is rated IP66, helping protect internal circuitry from dust and washdown exposure. Communication is handled through Profibus DP V0/V1 3 Mbaud, allowing cyclic setpoints and diagnostic data to travel over the same shielded network used by other decentralized drives on the line.

Electromagnetic compatibility is supported by an integral 1 A filter, which removes the need for a separate external RFI module on branch circuits of similar current. The control electronics use an extended 24 V external supply, so parameters can be accessed even when the main power is isolated. This separate low-voltage feed allows communication and setup functions to remain available during service conditions. Operator interaction is limited because the unit has no display, so setup is handled over the network or with a handheld tool. Wiring enters through molded glands because of the lack of a terminal box, which helps preserve the enclosure seal while keeping the housing compact.