What this firing PCB does for the 3RW44
The 3RW4743-0VC70 is the firing printed circuit board for the Siemens 3RW44 soft starter family, specifically the Size 3 variant that mates with the 3RW4443 base unit. It handles the gate-drive signals for the thyristor stack at 460 V line voltage. This is a subassembly, not a complete soft starter — it replaces the control board inside the 3RW4443 enclosure when the firing circuit fails or needs a revision swap. The 460 V rating means it's wound for the higher-voltage winding of the 3RW44 line, not the 230 V or 400 V variants.
Compliance and documentation
Substance prohibitance date of 03/01/2017 confirms RoHS compliance from that date forward. The PCB carries the standard Siemens declaration of conformity for the 3RW44 series; no separate UL or IEC listing is recorded for this subassembly alone.