Auxiliary contacts provide critical position feedback in high-voltage contactors, allowing control systems to reliably determine the state of the main power contacts. In Rincon Power REC35 Series contactors, the auxiliary contact uses a mechanically actuated microswitch linked directly to the main contact movement, ensuring accurate and reliable correlation between the power and signal domains. This application note explains the operating principle, mechanical design, and engineering significance of that implementation, with emphasis on reliability and state correlation. It is intended for engineers integrating contactor state feedback into Battery Management Systems, PLCs, and other control hardware in battery energy storage, electrified transport, and DC power distribution.
