What the ON-delay setting means for your sequence
The 3RT1926-2ED11 is a SIRIUS auxiliary switch with an ON-delay function — it closes its contacts a set time after the contactor coil energises, not immediately. That adjustable time window runs from 0.05 s to 1 s, set via a potentiometer on the device. This is the part you spec when a downstream action must wait — staging a second motor start after the first reaches speed, sequencing a fan before a burner, or delaying a signal until a valve has fully stroked. The delay is additive ON-delay only; there is no OFF-delay or pulse-shaping option on this variant.
Contact ratings and coil voltage — what governs the fit
The switch contacts are rated 3 A maximum, but the voltage derates the current: 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V. That means the 24 V control circuit can carry a full amp, but a 250 V signal drops to 0.1 A — enough for a PLC input or a small relay coil, not a power load.
Mechanical fit — clips on, no tools needed
Mounting is clip-on: the switch snaps onto the front of a SIRIUS 3RT contactor without screws. The 33 mm width, 46 mm height, and 73 mm depth keep it within the contactor's envelope — no extra DIN-rail space consumed. The recovery time after a drop-out is 150 ms — the delay circuit resets in that window before the next cycle can start. Wiring accepts solid or stranded conductors 18-14 AWG, with 2x (20-14) AWG for solid.