175H2904 by Danfoss

The 175H2904 variable frequency drive is manufactured by Danfoss and belongs to the VLT 3000 Variable Speed Drives series. It is designed to modulate the speed of three-phase induction motors in automated material-handling, pumping, and ventilation equipment. By converting a fixed mains input into a user-defined frequency and voltage profile, the unit provides closed-loop speed control, soft starts, and reduced mechanical stress for machinery deployed in continuous industrial duty. This operating method helps connected equipment run more smoothly during startup, speed changes, and routine process control.

An analog reference can be connected through an input impedance of 10 k?, ensuring minimal loading on process controllers. Logic commands are accepted on a galvanically isolated digital bus powered by 24 VDC with a maximum draw of 140 mA, so standard PLC I/O modules can drive the terminals without relays. The drive accepts a three-phase mains window centered on 380/400/415 V ±10% at a supply frequency of 50 or 60 Hz. At full load, the conversion stage achieves an efficiency of 96%, turning most of the incoming energy into motor power and limiting enclosure heating. The inverter provides output frequencies up to 120 Hz, allowing overspeed operation when required. Rated mechanical output is 2.2 kW, enabling direct connection to medium-sized pumps or conveyors.

Electrical loading parameters set the allowable wiring and thermal limits. The input line current is 5.6 A under steady conditions and 6.2 A for 60-second overloads, while the inverter supplies 4.8 A continuously and 5.3 A for one-minute transients on the motor side. Power loss is restricted to 100 W at maximum load, which simplifies cabinet ventilation. Continuous operation is permitted up to an ambient temperature of 40°C without derating, and an unshielded motor cable can run as far as 1000 ft before reflected-wave effects must be evaluated. This arrangement supports installation in distributed panels that serve remote motors on conveyors or fan sections while keeping performance predictable over longer cable runs.