SIRIUS 3RF2330-1AA22 — solid-state contactor, 30 A AC-51, single-phase
The Siemens SIRIUS 3RF2330-1AA22 is a single-phase solid-state contactor rated 30 A in AC-51 duty (resistive loads). It switches via zero-point switching, which means the thyristor only fires at the voltage zero crossing — that keeps inrush and electrical noise low on heater banks, ovens, and lighting strips. Side-by-side mounting is allowed, but at 40 °C ambient you need to derate — the 30 A AC-51 figure assumes free air at 40 °C. The power dissipation at rated load is 33 W in the hot state, so keep ventilation slots clear when packing multiple units.
The AC-51 rating of 30 A is the key number for resistive loads. Under UL 508 the same contactor is rated 27 A, so a panel destined for North America should be sized to the lower figure. Minimum switching current is 500 mA — below that the thyristor may not latch cleanly, so don't use it for dry-contact signal switching. On/off delay is 40 ms plus a maximum of one half-wave (about 8 ms at 60 Hz). That's fast enough for most temperature control loops but not for safety stop circuits — the 7 mm contact gap on the main contacts is an isolation gap, not a safety disconnection. Wiring: main circuit terminals accept 1x (0.5-2.5 mm²) solid or 2x (0.5-1.0 mm²) solid, and 1.5-6 mm² stranded. For AWG, main contacts take 2x 14-10 AWG. Control terminals are screw-type, same as the mains. The I²t maximum is 1,800 A²s — that's the let-through energy the thyristor can survive during a short-circuit before the upstream fuse clears. Siemens recommends NH fuses 3NA6810, DIAZED 5SB2711, or NEOZED 5SE2320, all with a smaller rated current than the semiconductor relay.
Compliance: RoHS compliant per the substance prohibition date of July 1, 2006. The insulation voltage is rated 600 V.