Active SIRIUS relay, sized for AC-51 heating duty
The 3RF2190-1AA45: It carries 50 A at AC-51 (resistive heating duty) and 50 A per UL 508, with a maximum ampacity figure of 90 A on the housing label — the AC-51 number, not the 90 A, is the rating that governs continuous heating-element switching. Per-pole dissipation is 118 W at full load, which drives the thermal budget for cabinet layout and forced-air decisions inside any enclosure it lands in.
Operating window, insulation class, and switching behaviour
ON-delay and OFF-delay are each 1 ms plus at most one additional half-wave — zero-point switching plus that half-wave floor is what keeps turn-on transients off the load on the first cycle after a control signal arrives. Reverse (off-state) current through the thyristor is 10 mA — relevant when the relay feeds a low-power load, because that leakage floor plus the 500 mA operational minimum defines the working envelope at the bottom end.
Thermal envelope and the derating anchor at 40 °C
Operating temperature spans -25... +60 °C, storage -55... +80 °C, with derating temperature anchored at 40 °C — past that point the published current curve steps down and cabinet-side cooling (or spacing) becomes mandatory to hold the 50 A AC-51 figure. Side-by-side mounting is permitted, which is useful in a multi-loop heater panel where the SSR rows stack tightly along the DIN rail — but the 40 °C derating anchor still applies to the bank as a whole, not just to the relay fitted alone.
Footprint, wiring, and short-circuit coordination
Body dimensions are 22.5 mm wide × 48 mm deep × 85 mm tall, screw-fixed onto the mounting surface — a slim 22.5 mm footprint that lets multi-loop panels stack tightly along a DIN rail. Short-circuit coordination is documented against the 3NA6812 NH fuse and the 5SE2335 NEOZED fuse — both are sized below the relay's continuous current so they clear the 6 600 A²·s I²t let-through before the output stage is damaged.
Compliance anchor and panel-side integration
With 600 V insulation, a 50 A AC-51 rating, and a 22.5 mm DIN-rail-ready footprint, the 3RF2190-1AA45 drops into a heater or soft-load panel without re-engineering the surrounding wiring — the control-side 30 V DC / 13 mA draw interfaces directly with a PLC output card or a low-voltage driver.