09.F4.S1D-3420 by KEB

The 09.F4.S1D-3420 frequency inverter is produced by KEB for the F4 Combivert Frequency Inverters series. Classified as a COMBIVERT F4 unit, it converts a fixed three-phase 400 V AC input into a variable-frequency output that matches motor speed requirements. This operating principle supports conveyor, pump, and general motion applications in industrial automation. An integrated braking transistor directs regenerated energy to an external resistor, removing the need for a separate braking module and allowing shorter deceleration times.

The inverter uses a Compact D-size housing with an IP20 protection rating, making it suitable for installation inside a clean electrical cabinet. Its supply voltage can range from 305 to 500 V without derating, and a 10 A mains fuse protects the input path. Standard control and fieldbus options are included for connection to common automation systems. Continuous motor output reaches 1.5 kW, while the apparent output capacity is 2.8 kVA. Brief overloads can raise the output current to 7.4 A when additional torque is required during acceleration. Dynamic braking requires a resistor with a minimum resistance of 160 ?, and the internal braking circuit can handle 5 A of current. Nominal input current is 4.5 A, while the protective trip level is 9 A to prevent excessive loading of the incoming conductors.

The output stage delivers up to 4.5 A of fundamental current and sustains a rated motor line current of 4.1 A during continuous operation. Its switching devices operate with a carrier frequency of 4 kHz, balancing motor current control with switching losses and audible noise. The inverter dissipates approximately 60 W as heat during rated operation, so the cabinet must provide adequate airflow around the heat sink. Thermal protection responds if the heat-sink temperature reaches 85 °C, reducing the risk of damage from excessive internal temperature. The permitted ambient operating range extends from -10 °C to 45 °C. Relative humidity may reach 95 percent when the surrounding air remains noncondensing, so the enclosure should prevent moisture accumulation while maintaining sufficient ventilation.