Product Description:

The SM 35/70-T is an AC inverter produced by Bosch Rexroth Indramat for the SM AC Inverters series. Installed between the mains and a three-phase motor, it modulates voltage and frequency so automated machinery can accelerate, decelerate, or hold a commanded speed. Its tachometer feedback lets controllers monitor rotor velocity directly, supporting closed-loop regulation in assembly cells and process lines.

The power section delivers a rated output current of 35 A, which is sufficient for medium-frame motors in conveyors or tooling spindles. For short acceleration bursts, it can supply 70 A for two seconds, helping machines clear high-inertia starts. Internal losses are limited to 250 W, so cabinet ventilation stays moderate. Control electronics draw only 26 W, keeping auxiliary supplies small. When ambient temperature rises above the reference, output is reduced by 1.2%/K, which provides a straightforward derating factor. The inverter needs a +24 V enable signal and offers a 10 kΩ command impedance that is compatible with PLC sourcing outputs. A ready relay rated for 24 V at 1 A DC provides status to safety chains. The tacho terminal delivers 2.7 V per 1000 rpm for external speed monitoring, and a blower connector energizes a 24 VDC fan rated at 100 mA when forced cooling is required. Motor overtemperature is sensed at 140 °C to help prevent winding damage.

The drive is specified for continuous duty at an ambient benchmark of 45 °C, with functional limits that extend to 55 °C before the converter must be derated or shut down. Application at elevations up to 1000 m AMSL is supported without additional cooling provisions. A wide control span of 1:10,000 allows the same unit to handle both fine positioning speeds and full-speed production rates. Because the enclosure has an IP00 rating, the device is intended for installation inside a protected electrical cabinet where dust and liquid exposure are controlled. The open-frame construction also aids access and reduces overall cabinet depth.