What this combination starter packs into the S2 frame
The 3RA1135-4EB34-1BB4 is a non-reversing combination starter from the Siemens SIRIUS family, S2 frame size, rated 22-32 A with a 24 VDC control voltage. It integrates a contactor, overload relay, and disconnecting means into a single DIN- or panel-mount unit — one part number replaces the three-piece assembly a panel builder would otherwise source and wire separately. The control circuit runs on 24 VDC, which keeps the coil draw low and avoids the hum and heat of an AC coil in a sealed enclosure. The auxiliary contact complement — one SPDT NO/NC on the MSP plus one NO on the contactor — gives the controls integrator a feedback signal for the PLC and a status contact for the HOA station without adding a side-mount block.
UL listing and panel integration
This starter carries UL File E156943, Volume 1, Section 14, which covers industrial control equipment under UL 508. That file reference is the authority signal a site electrical engineer needs to sign off on the SCCR coordination study — the combination starter's short-circuit current rating is established as a tested assembly, not a stack of individually rated components. The S2 frame is sized for the 22-32 A band and mounts on standard DIN rail or directly to a panel backplate. For a panel OEM wiring up a motor control center bucket, the single-piece footprint saves roughly 30-40% of the panel width compared to a contactor-plus-overload-plus-disconnect build, and the pre-wired control terminals reduce the wiring error rate on the line.