What the AC-1 rating means for resistive loads
The Siemens 3RF3340-3AA04 is a 1-pole solid-state contactor from the SIRIUS 3RF33 family, rated 40 A in AC-1 duty at 40 °C. AC-1 covers resistive or slightly inductive loads — heating elements, incandescent lighting, or resistive furnace banks — where inrush current stays close to the steady-state draw. For a glass or ceramics furnace, this means it can cycle the heating elements on a 40 A resistive circuit without the contact wear a mechanical contactor would see.
Supply and control voltage range
The load supply accepts 48-460 V AC, covering standard three-phase and single-phase line voltages across most industrial regions. The control input is 24 V DC, which is the standard PLC-level signal — no additional interface relay needed when driven from a 24 V DC digital output card. The ring cable lug connection on the power terminals suits permanent wiring in a panel; no spring-cage or screw-clamp tooling required at the lug end.
The 27 mm width fits one standard module slot, so it integrates into a crowded panel without forcing a wider enclosure. The ring cable lug connection means the installer crimps a ring terminal onto the load wire and bolts it down — no special push-in or screw-clamp tool required at the power terminals.