Product Description:

The SM 20/30-LN is an AC inverter produced by Bosch Rexroth Indramat within the SM AC Inverters series. As a drive module, it converts a DC link supply into variable AC output for closed-loop speed and torque regulation of asynchronous or synchronous motors used in automated machinery. By coordinating with external control electronics, the inverter maintains commanded motor performance for conveyors, packaging lines, and other motion-based processes. It modulates output voltage and frequency so the connected motor can respond smoothly to changing load and speed demands.

The unit draws its DC power from a supply bus that may range from 24 V up to 715 V, enabling integration in both low-voltage test rigs and high-energy production equipment. At an ambient temperature of 35 °C, it can deliver a continuous phase current of 20 A, while short-term overloads can be met with a peak capability of 30 A for two seconds to accelerate heavy loads. Drive commands are accepted through an analog interface with an input resistance of 10 kΩ, a value that minimizes loading on PLC voltage sources and preserves signal integrity across long cable runs. This also helps the inverter follow external reference signals without placing excessive demand on the control circuit.

Internal switching devices dissipate 250 W at rated load, so the manufacturer specifies 100 mm of minimum clearance around the 109 mm-wide, 325 mm-deep housing to maintain airflow. With an IP00 protection class, the drive must be mounted inside a closed control cabinet, and that open design leaves touch protection to the enclosure rather than to the inverter housing itself. Feedback wiring can be routed up to 100 m to the motor's encoder, allowing distant axis placement while staying within permitted signal quality. Integrated temperature monitoring trips when windings reach +140 °C, protecting the machine against excessive duty cycles or obstructed cooling paths.