Product Description:

The 178B0903 is an AC frequency converter produced by Danfoss and assigned to the VLT 5000 Frequency Converters series. Within an automation cell, the converter modulates three-phase mains power to regulate induction motor speed, allowing proportional torque control in pumps, fans, and general machinery. The unit occupies a slim, book-style frame, so it fits in densely arranged electrical cabinets and serves as the central power stage while ancillary cards handle process feedback.

The mechanical housing is a book-style IP20 enclosure that shields live parts while remaining open to cabinet airflow. For input power, it accepts a 200–240 V three-phase supply, which is suitable for low-voltage plant networks without step-up transformers. At 110% overload, the drive delivers 1.1 kW. The extended configuration with 24 V backup and a brake chopper provides controlled energy dissipation and retains parameters during brief mains power losses. An internal RFI stage with Class A1 and Class B filtering limits conducted emissions that could interfere with nearby instrumentation. Motor commands are generated through a process control card, and a front-mounted display is included for parameter entry and status viewing.

When an application requires 160% short-term torque, the converter can supply 0.75 kW, maintaining motion during acceleration peaks without requiring a larger cabinet footprint. Position-linked tasks are supported by the SyncPos programmable controller option, which adds incremental indexing to the basic speed-control loop. The drive uses uncoated boards, which permit direct thermal transfer but require suitable protection from moisture and airborne contaminants inside the cabinet. Communication hardware includes no fieldbus option, so commands travel through hardwired input and output connections. The process control card manages application signals, while the display provides direct access to operating values and drive settings.