Robertshaw 574-C Adder Subtracter Drive

Robertshaw 574-C Adder Subtracter Drive is a compact legacy control module from the Robertshaw line, designed to perform arithmetic operations within a larger control system. The 574-C model is configured for 117V alternating current operation and supports 50 or 60 Hz mains, aligning with common North American electrical standards. It draws 5 watts of active power and presents a 6 VA apparent power rating, indicating a low‑power, line‑voltage device suitable for integration alongside other control components in vintage equipment. As an Adder Subtracter Drive, it serves as a specialized module within broader circuits that require basic arithmetic processing as part of decision logic, typically connected to compatible relays, sensors, or timers in legacy installations. The 574-C designation identifies this particular variant within Robertshaw’s Adder Subtractor family, distinguishing its configuration and terminal arrangement from other models in the catalog. While focused on the verified electrical characteristics, the component’s role is anchored in enabling simple, direct arithmetic operations within a panel‑mounted control assembly, contributing to the reliability and predictability of older control systems that relied on fixed, discreet hardware modules rather than modern integrated circuits.