What this auxiliary contactor is
The Siemens 3RH2353-1DG40-0KA0 is a SIRIUS auxiliary contactor, size S00, with 5 normally open (NO) instantaneous contacts. The coil is rated 125 VDC and includes a built-in varistor surge suppressor, which clips voltage spikes from the inductive coil during de-energization — this protects downstream PLC outputs and reduces electrical noise on the DC control bus.
Switching capacity across the DC voltage range
The contact ratings are specified per the DC switching curve: at 24 V rated value the contacts carry 10 A, at 60 V it drops to 4.7 A, at 110 V it is 3 A, and at 220 V it is 1.2 A. At 440 V the rating is 0.5 A, and at 600 V it is 0.26 A.
The size S00 frame is the smallest Siemens contactor footprint, so it fits in compact panel layouts alongside motor starters or PLC racks.
The substance prohibitance date is 07/01/2006, indicating RoHS compliance from that date. The product extension auxiliary switch is listed as 'No' — this is a standalone contactor block, not a stackable add-on switch.